American Journal of Respiratory and Critical Care Medicine

Drug-induced liver injury (DILI) is a problem of increasing significance, but has been a long-standing concern in the treatment of tuberculosis (TB) infection. The liver has a central role in drug metabolism and detoxification, and is consequently vulnerable to injury. The pathogenesis and types of DILI are presented, ranging from hepatic adaptation to hepatocellular injury. Knowledge of the metabolism of anti-TB medications and of the mechanisms of TB DILI is incomplete. Understanding of TB DILI has been hampered by differences in study populations, definitions of hepatotoxicity, and monitoring and reporting practices. Available data regarding the incidence and severity of TB DILI overall, in selected demographic groups, and in those coinfected with HIV or hepatitis B or C virus are presented. Systematic steps for prevention and management of TB DILI are recommended. These include patient and regimen selection to optimize benefits over risks, effective staff and patient education, ready access to care for patients, good communication among providers, and judicious use of clinical and biochemical monitoring. During treatment of latent TB infection (LTBI) alanine aminotransferase (ALT) monitoring is recommended for those who chronically consume alcohol, take concomitant hepatotoxic drugs, have viral hepatitis or other preexisting liver disease or abnormal baseline ALT, have experienced prior isoniazid hepatitis, are pregnant or are within 3 months postpartum. During treatment of TB disease, in addition to these individuals, patients with HIV infection should have ALT monitoring. Some experts recommend biochemical monitoring for those older than 35 years. Treatment should be interrupted and, generally, a modified or alternative regimen used for those with ALT elevation more than three times the upper limit of normal (ULN) in the presence of hepatitis symptoms and/or jaundice, or five times the ULN in the absence of symptoms. Priorities for future studies to develop safer treatments for LTBI and for TB disease are presented.

  • Methods

  • The Liver: Structure and Function

    • Hepatic Drug Metabolism: Transporters, Enzymes, and Excretion

  • Drug-induced Liver Injury: General Concepts

    • Definition

    • Dimensions of the Problem

    • Pathogenesis of DILI

    • Hepatic Enzyme Measurement

    • Types of DILI

  • DILI during Treatment of Latent TB Infection

    • Isoniazid

    • Rifampin

    • Isoniazid and Rifampin

    • Pyrazinamide

    • Rifampin and Pyrazinamide

    • Rifabutin

    • Ethambutol

    • Fluoroquinolones

  • Hepatotoxicity during Treatment of TB Disease

    • Age over 35

    • Children

    • Sex

    • Cofactors

    • Abnormal Baseline Transaminases

    • Acetylator Status

    • Other Factors

    • Regimen

    • HIV-infected Individuals

    • Hepatitis B

    • Hepatitis C

    • DILI with Second-line Anti-TB Agents

  • Recommendations regarding TB DILI

    • Program Infrastructure

    • Provider Education and Resources

    • Pretreatment Clinical Evaluation

    • Patient Education

    • Medication Administration and Pharmacy

    • Treatment of LTBI

    • Treatment of TB Disease

  • Priorities for Research of Hepatotoxicity in Treatment of LTBI and of TB Disease

  • Conclusions

Material presented here was generated by a multidisciplinary symposium held on November 13–14, 2002, which included presentations and discussion by specialists in tuberculosis (TB), pharmacology, and hepatology. This information was supplemented by material obtained through literature searches performed before and after the symposium during the course of this project. PubMed searches used various combinations of the terms “tuberculosis,” “treatment,” “hepatitis,” “liver injury,” “hepatotoxicity,” “adverse events,” “latent,” “infection,” and/or individual names of the anti-TB medications mentioned here. The bibliographies of publications were also reviewed for additional references. Publications were evaluated for numbers of patients treated, regimens used, incidence and severity of hepatotoxicity, confounding features, and type of publication.

The liver is situated between the alimentary tract and the systemic circulation to maximize processing of absorbed nutrients and to minimize exposure of the body to toxins and foreign chemicals. Consequently, the liver may be exposed to large concentrations of exogenous substances and their metabolites.

Hepatic Drug Metabolism: Transporters, Enzymes, and Excretion

The splanchnic circulation carries ingested drugs directly into the liver, a phenomenon known as the “first pass” through the liver. Metabolic enzymes convert these chemicals through phase 1 pathways of oxidation, reduction, or hydrolysis, which are carried out principally by the cytochrome P450 class of enzymes. Phase 2 pathways include glucuronidation, sulfation, acetylation, and glutathione conjugation to form compounds that are readily excreted from the body. Other subsequent steps include deacetylation and deaminidation. Many drugs may be metabolized through alternative pathways, and their relative contributions may explain some differences in toxicity between individuals. In phase 3 pathways, cellular transporter proteins facilitate excretion of these compounds into bile or the systemic circulation. Transporters and enzyme activities are influenced by endogenous factors such as circadian rhythms, hormones, cytokines, disease states, genetic factors, sex, ethnicity, age, and nutritional status, as well as by exogenous drugs or chemicals (1). Bile is the major excretory route for hepatic metabolites. Compounds excreted in bile may undergo enterohepatic circulation, being reabsorbed in the small intestine and re-entering the portal circulation (2).

Definition

Drug-induced liver injury (DILI) is ultimately a clinical diagnosis of exclusion. Histologic specimens of the liver are often not obtained. Other causes of liver injury, such as acute viral hepatitis, should be methodically sought, and their absence makes the diagnosis plausible. Usually, the time of onset to acute injury is within months of initiating a drug. Rechallenge with the suspected offending agent with more than twofold serum alanine aminotransferase (ALT) elevation, and discontinuation leading to a fall in ALT, is the strongest confirmation of the diagnosis (3). Rechallenge may, in some instances, endanger the patient and is usually confined to essential drugs or used when multiple potentially hepatotoxic drugs have been administered concomitantly (4).

Dimensions of the Problem

DILI accounts for 7% of reported drug adverse effects, 2% of jaundice in hospitals, and approximately 30% of fulminant liver failure (4, 5). DILI has replaced viral hepatitis as the most apparent cause of acute liver failure (6). A brief search of commercial pharmacopoeia databases suggests there are more than 700 drugs with reported hepatotoxicity and approved for use in the United States (7). With an estimated background rate of idiopathic liver failure of 1 in 1,000,000 (4, 8), the U.S. Food and Drug Administration (FDA) has withdrawn drugs or mandated relabeling for severe or fatal liver injury exceeding 1 in 50,000 individuals (5, 8, 9).

Pathogenesis of DILI

DILI may result from direct toxicity of the primary compound, a metabolite, or from an immunologically mediated response, affecting hepatocytes, biliary epithelial cells, and/or liver vasculature. In many cases, the exact mechanism and factors contributing to liver toxicity remain poorly understood. Predictable DILI is generally characterized by certain dose-related injury in experimental animal models, has a higher attack rate, and tends to occur rapidly. Injurious free radicals cause hepatocyte necrosis in zones farthest from the hepatic arterioles, where metabolism is greatest and antioxidant detoxifying capacity is the least (10, 11).

Unpredictable or idiosyncratic reactions comprise most types of DILI. These hypersensitivity or metabolic reactions occur largely independent of dose and relatively rarely for each drug, and may result in hepatocellular injury and/or cholestasis. Hepatocyte necrosis is often distributed throughout hepatic lobules rather than being zonal, as is often seen with predictable DILI. In hypersensitivity reactions, immunogenic drug or its metabolites may be free or covalently bound to hepatic proteins, forming haptens or “neoantigens.” Antibody-dependent cytotoxic, T-cell, and occasionally eosinophilic hypersensitivity responses may be evoked. Released tumor necrosis factor-α, interleukin (IL)-12, and IFN-γ promote hepatocellular programmed cell death (apoptosis), an effect opposed by IL-4, IL-10, IL-13, and monocyte chemotactic protein-1 (12).

Metabolic idiosyncratic reactions may result from genetic or acquired variations in drug biotransformation pathways, with synthesis or abnormally slow detoxification of a hepatotoxic metabolite. Metabolic idiosyncratic reactions may have a widely variable latent period, but recur within days to weeks after re-exposure (4).

Hepatic Enzyme Measurement

An increase in serum ALT, formerly known as serum glutamate pyruvate transaminase (SGPT), is more specific for hepatocellular injury than an increase in aspartate aminotransferase (AST or serum glutamic oxaloacetic transaminase [SGOT]), which can also signify abnormalities in muscle, heart, or kidney (13, 14).

Serum enzyme concentrations are measured by functional catalytic assays with normal values established from “healthy” populations. The normal range lies within 2 standard deviations of the mean of the distribution, with 2.5% of persons who are otherwise healthy having concentrations above and below the limits of normal on a single measurement (15). Populations used to set standard values in the past probably included individuals with occult liver disease, whose exclusion has led to decreases in the upper limit of normal (ULN) (16). Interlaboratory variation in assay results can be substantial. Consequently, comparison of multiples of the ULN has become standard (13, 14).

In an individual, transaminases may vary as much as 45% on a single day, with the highest levels occurring in the afternoon, or 10 to 30% on successive days. ALT and AST elevation may occur after exercise, hemolysis, or muscle injury. A recent retrospective review of healthy volunteers participating in drug trials who received placebo found that 20% had at least one ALT value greater than the ULN, and 7% had one value at least two times the ULN (17). Serum hepatic transaminase concentration tends to be higher in men and in those with greater body mass index. Children and older adults tend to have lower transaminase concentrations. The National Academy of Clinical Biochemistry recommends that laboratories establish reference limits for enzymes adjusted for sex in adults, and for children and adults older than 60 years (13, 14).

Increases in alkaline phosphatase and/or bilirubin with little or no increase in ALT indicate cholestasis. Alkaline phosphatase concentration may also increase because of processes in bone, placenta, or intestine. An increased concentration of serum γ-glutamyl transpeptidase, an inducible enzyme expressed in hepatic cholangioles, is useful in distinguishing liver-related from other organ-related alkaline phosphatase increases (5, 18). Jaundice is usually detectable on the physical examination when serum bilirubin exceeds 3.0 mg/dl.

Laboratory monitoring.

A benefit of ALT and/or bilirubin monitoring in preventing or alleviating drug-induced liver injury has not been rigorously tested. A recent small nonrandomized report suggested that monitoring may decrease the severity of pyrazinamide-induced liver injury (19). Disadvantages of laboratory monitoring include questionable cost-efficacy of frequent testing for rare adverse events, development and progression of injury between testing events, unclear enzyme thresholds for medication discontinuation, and confusion of hepatic adaptation with significant liver injury. The cost of obtaining AST with ALT is often marginal and may be useful in identifying alcohol- related transaminase elevation, where the AST is characteristically higher than the ALT.

The diagnosis of a superimposed injury may be difficult with initially abnormal or fluctuating transaminases. Prior laboratory data may be of use in this regard. Monitoring and the use of a potentially less hepatotoxic regimen is generally recommended for those with preexisting liver disease in the hope that superimposed DILI may be detected preclinically and mitigated. Transaminase elevation during the course of anti-TB therapy may in some instances actually represent coincidentally developed hepatitis A, B, or C (20, 21).

Types of DILI

A variety of clinical syndromes may be seen with DILI, even with a single drug.

Hepatic adaptation.

Exposure to certain drugs may evoke physiologic adaptive responses (18). The induction of survival genes, including those that regulate antioxidant, antiinflammatory, and antiapoptotic pathways, may attenuate toxin-related injurious responses. Such injury may also stimulate hepatocyte proliferation and protective adaptation. Asymptomatic, transient elevations of ALT may reflect slight, nonprogressive injury to hepatocyte mitochondria, cell membranes, or other structures. Such injury rarely leads to inflammation, cell death, or significant histopathologic changes. Certain toxins, such as ethanol, possibly interfere with these adaptive protective responses. Excessive persistence of an adaptive response may, in some instances, render hepatocytes more vulnerable when they are subjected to additional new insults (22). The induction of hepatic microsomal (cytochrome P450) enzymes, capable of metabolizing the inducing medication (4, 18), is another form of hepatic adaptation.

Drug-induced acute hepatitis or hepatocellular injury.

A transaminase threshold for clinicopathologically significant drug-induced hepatitis has not been systematically determined for most medications. Patients who take phenytoin often have transaminase elevation up to three times the ULN, but liver biopsies do not reveal significant pathology (23). However, in patients treated for rheumatoid arthritis with methotrexate, microscopic evidence of liver injury has been found for any transaminase elevation above the ULN (24).

Patients with acute hepatocellular injury may be asymptomatic or may report a prodrome of fever and constitutional symptoms, followed by nausea, vomiting, anorexia, and lethargy. Histopathology may reveal focal hepatic necrosis, with bridging in severe cases (4).

Markedly increased transaminase concentrations followed by jaundice imply severe liver disease with a 10% possibility of fulminant failure, a maxim known as “Hy's Law,” after the late hepatologist and DILI expert Hyman Zimmerman. Coagulopathy may develop 24 to 36 hours after onset, although this can subsequently resolve. Coagulopathy persisting beyond 4 days is a poor prognostic sign in acetaminophen-related hepatotoxicity (13, 14).

Nonalcoholic fatty liver disease.

Steatosis, or simple fatty liver, is most commonly caused by obesity, insulin resistance, and probably alterations in triglyceride metabolism. Ethanol, steroids, and highly active antiretroviral therapy (HAART) are associated with the development and exacerbation of nonalcoholic fatty liver disease (2528). Constitutional symptoms, nausea, vomiting, or abdominal pain are uncommon. Laboratory findings in severe cases include hypoglycemia, increased serum transaminase concentrations, prolonged coagulation times, and metabolic acidosis (4, 27, 29). Most instances of drug-induced steatosis are reversible, if the offending agent is stopped. Persistent steatotic injury may progress to steatohepatitis, characterized histopathologically by hepatic inflammatory and fatty infiltration, and by a subsequently higher risk of cirrhosis (30).

Granulomatous hepatitis.

Granulomata are common, nonspecific findings in liver histology and are potentially related to infectious, inflammatory, or neoplastic etiologies. Hypersensitivity reactions to drugs, such as allopurinol, quinidine, sulfonamides, and pyrazinamide, are a common cause of this type of lesion. Patients may have fever, lethargy, myalgias, rash, lymphadenopathy, hepatosplenomegaly with increased serum ALT concentration, and even vasculitis (4, 31).

Cholestasis.

Bland cholestasis, typically reported with estrogen treatment, consists of asymptomatic, usually reversible, increases in serum alkaline phosphatase and bilirubin concentration, caused by a failure of bilirubin transport. There is a lack of inflammation in liver tissue (4).

Chemical cofactors for DILI.

Ethanol induces cytochrome P450 2E1, which promotes metabolism of ethanol itself, acetaminophen, and others (32). Ethanol metabolism yields acetaldehyde, which contributes to glutathione depletion, protein conjugation, free radical generation, and lipid peroxidation. Chronic ethanol abuse activates hepatic collagen-producing sinusoidal (stellate) cells, potentially contributing to fibrosis (33). Some medications, such as calcium channel blockers, may influence cytochrome P450 metabolism of potentially hepatoxic drugs, such as simvastatin, which may lead to DILI (34).

Preexisting liver disease.

Abnormal baseline transaminases are an independent risk factor for DILI (3539). Patients with HIV and hepatitis C, however, appear to have increased frequency of antiretroviral medication–related DILI (26, 27). The severity of DILI, when it occurs, may be greater in patients with underlying liver disease (40), likely reflecting a summation of injuries.

DILI may occur with all currently recommended regimens for the treatment of latent TB infection (LTBI), including isoniazid for 6 to preferably 9 months, rifampin for 4 months, or isoniazid and rifampin for 4 months (41). This is also true of two-drug regimens of pyrazinamide with either ethambutol or a fluoroquinolone used to treat contacts of multidrug-resistant (MDR) TB cases (4244). Metabolic idiosyncratic reactions appear to be responsible for most DILI from the first-line anti-TB medications and fluoroquinolones.

Isoniazid
Metabolism.

Isoniazid is cleared mostly by the liver, primarily by acetylation by N-acetyl transferase 2 (NAT-2). Acetyl-isoniazid is metabolized mainly to mono-acetyl hydrazine (MAH) and to the nontoxic diacetyl hydrazine, as well as other minor metabolites (45). Interindividual variation in plasma elimination half-life (t1/2), independent of drug dose and concentration, is considerable. Individuals with prolonged t1/2 have extended exposure to the drug. Genetic polymorphisms of NAT-2 correlate with fast, slow, and intermediate acetylation phenotypes (4547). Microsomal enzymes (e.g., cytochrome P450 2E1) further metabolize isoniazid intermediates through phase 1 pathways (46).

Acetylator status.

In fast acetylators, more than 90% of the drug is excreted as acetyl-isoniazid, whereas in slow acetylators, 67% of the drug is excreted as acetyl-isoniazid and a greater percentage of isoniazid is excreted as unchanged drug into the urine. The influence of acetylation rate on isoniazid hepatotoxicity is controversial. Most studies on this question involved patients on multidrug regimens for TB disease and relied on phenotypic assays of acetylation, which can be imprecise (45). Fast acetylators may be misidentified as slow if they exhibit delayed drug absorption during blood sampling at limited time points (46). Early studies suggested that fast acetylators were at higher risk for hepatic injury because they generated more acetyl-isoniazid, which could be further metabolized to other toxic intermediaries (45, 48, 49). However, fast acetylators clear MAH more rapidly. Slow acetylators may actually have greater cumulative MAH exposure. Increased susceptibility among slow acetylators (31, 50) or a lack of correlation with acetylation rate has been reported (51). NAT-2 genotyping by polymerase chain reaction recently demonstrated that slow acetylators experience transaminase elevations of more than three times the ULN more frequently than rapid acetylators (26 vs. 11%) (45). Slow acetylators also had higher peak ALT than did fast acetylators and, when rechallenged with isoniazid, more frequently developed transaminase elevation of at least three times the ULN. The significance of these findings awaits further studies.

Mechanism of injury.

Reactive metabolites of MAH are probably toxic to tissues through free radical generation (48). In rats, the free radical scavenger glutathione-related thiols, and antioxidant glutathione peroxidase and catalase activities, are diminished by isoniazid, although glutathione reductase activity is increased (52, 53). The antioxidant N-acetyl-cysteine, a substrate for glutathione synthesis, inhibits isoniazid-induced liver injury in pretreated rats (52), with unknown relevance in humans.

Additional metabolic idiosyncratic mechanisms appear to be operative. The isoniazid metabolite acetyl-hydrazine covalently binds to liver macromolecules, a process mediated by microsomal enzymes (48). Patients with homozygous cytochrome P450 2E1 c1/c1 host gene polymorphism, who have enhanced cytochrome P450 2E1 activity, in one study had a higher risk of hepatotoxicity, particularly in slow acetylators (46).

Histopathology.

Nonspecific changes resemble those of viral hepatitis with nonzonal necrosis, and are massive in up to 10% of severe cases. Subacute hepatic necrosis can be seen in 30% of cases (54).

Drug interactions.

Isoniazid inhibits the activity of several cytochrome P450 2E and 2C enzymes, potentially increasing the plasma concentrations of other potentially hepatotoxic drugs, such as phenytoin and carbamazepine (5557). Rifampin appears to enhance a metabolic hepatocellular idiosyncratic reaction in patients receiving isoniazid, perhaps by promoting the formation of toxic isoniazid metabolites (58, 59).

Hepatic adaptation.

Up to 20% of individuals treated with isoniazid alone for LTBI may experience low-grade, transient, asymptomatic transaminase elevation (54, 60), most of which represents hepatic adaptation (18, 60).

Clinical presentation of hepatotoxicity.

Some individuals may be asymptomatic, whereas others may experience symptomatic hepatotoxicity at varying serum transaminase concentrations. Constitutional symptoms may be seen early in severe hepatotoxicity, and may last from days to weeks. Nausea, vomiting, and abdominal pain are seen in 50 to 75% of patients with severe illness, whereas fever is noted in 10% and rash in 5% of patients. Overt jaundice, dark urine, and clay-colored stools are late signs of clinical worsening. Coagulopathy, hypoalbuminemia, and hypoglycemia signify life-threatening hepatic dysfunction. The regression of isoniazid hepatotoxicity usually takes weeks. Recovery is complete in most after discontinuation of isoniazid (54).

Overall rates of hepatotoxicity.

Initial experience with isoniazid up to the 1960s indicated the rates of treatment-limiting adverse events were similar in placebo- and isoniazid-treated groups, except for gastrointestinal complaints (61), with hepatitis occurring relatively rarely. In the late 1960s, isoniazid's ability to cause asymptomatic elevations in hepatic transaminases and clinically significant hepatitis was recognized (54). In 1970, 19 of 2,321 Capitol Hill workers treated with isoniazid developed clinical signs of liver disease and two died of resulting complications (62). The U.S. Public Health Service (USPHS) surveillance study (63) of 14,000 isoniazid-treated individuals found an overall rate of significant, probable isoniazid hepatitis of 1%, with a cluster of seven of eight reported deaths in one city. A subsequent study, using passive detection, by the International Union Against Tuberculosis (IUAT), found the overall rate of hepatitis in patients receiving up to 12 months of isoniazid was 0.5 versus 0.1% receiving placebo (64).

From the 1970s to the 1990s, isoniazid-related hospitalization rates declined from as much as 5.0 per 1,000 treatment initiations to 0.1 to 0.2 (median, 0.15), and mortality rates fell from as high as 1.0 per 1,000 to 0–0.3 per 1,000 (median, 0.04) (40, 41, 62, 63). These declines may have been related to careful patient selection, education, and active monitoring for adverse reactions to isoniazid (65).

A study of isoniazid for treatment of LTBI, involving more than 11,000 patients in Seattle–King County, Washington, reported that symptomatic transaminase elevation of more than five times the ULN occurred in 0.1% of treatment initiations (66). Routine follow-up transaminase monitoring of asymptomatic individuals was not done in this clinic, which the authors estimated could have raised the incidence of significant transaminase elevation into the range of older studies, to approximately 0.6%. Hepatotoxicity rates could also have been higher if based on those patients actually taking medication, rather than on treatment initiations. The study generally demonstrated a relatively low risk of isoniazid hepatotoxicity within the context of a TB program providing patient education, specific instructions about adverse events, and monthly clinical observations.

A subsequent study of 3,788 patients treated for LTBI with isoniazid in San Diego, California, reported that transaminase elevations of three times the ULN in symptomatic individuals and five times the ULN in asymptomatic individuals occurred in 0.3% of cases (67). An observational study from 1996 to 2003 of isoniazid hepatotoxicity during LTBI treatment in 3,377 patients from Memphis, Tennessee, found AST elevations at least five times the ULN in 0.56% of those treated. In this study, AST was measured at baseline and 1, 3, and 6 months after treatment initiation. Only 1 of the 19 patients who developed significant transaminase elevation was symptomatic in this study. Seven of the 19 who experienced significant AST elevations consumed alcohol chronically, warranting biochemical monitoring. Testing for development of viral hepatitis was not reported, nor was use of concomitant potentially hepatotoxic medications (68).

Recent smaller treatment studies have reported significant transaminase elevation in 1 to 4% of those treated with isoniazid for LTBI (19, 69), whereas in recent large reviews, the range has been 0.1 to 0.56% (6668). Differences among these studies may be due to sample size variations in the definitions of hepatotoxicity, patient selection, and potential confounding causes of hepatotoxicity. Subgroup analyses to assess for those most at risk for isoniazid hepatotoxicity should be interpreted within the limitations and methodology of each study.

Timing.

Hepatotoxicity occurs generally within weeks to months rather than the days to weeks of onset seen with hypersensitivity reactions (52, 54). Unlike a classical hypersensitivity reaction, isoniazid rechallenge does not always elicit rapid recurrence of hepatotoxicity (54). Approximately 60% of the hepatotoxicity incidence in the USPHS study occurred in the first 3 months of treatment, and 80% of the incidence occurred in the first 6 months (63, 64, 68). A retrospective case fatality review found that the median interval from treatment initiation to symptom onset was 16 weeks (69).

Age.

Most isoniazid-associated hepatotoxicity is age associated. The Seattle study of symptomatic transaminase elevation showed ranges from 0% in those younger than 14 years to 0.28% in those older than 65 (66). The San Diego study reported a trend toward age-related hepatotoxicity, with only 15% of the study population aged 35 years or older (67). The Tennessee study reported that age-specific AST elevation more than five times the ULN ranged from 0.44% in those younger than 35 years to 2.08% for those older than 49 years (68), a statistically significant difference. In comparing these studies, 20% of the more than 11,000 patients in the Seattle study population were at least 35 years old, compared to 59% in the USPHS and 54.6% in the Tennessee studies. Sample sizes for this age group were comparable in the Seattle (n = 2,228) and the Tennessee studies (n = 1844). Differences in the findings among these studies may be attributed to differing definitions of hepatotoxicity, patient selection, and in ability to exclude confounding causes of hepatotoxicity. The severity of isoniazid-related hepatitis has been reported to also increase with age, with higher mortality in those older than 50 years (54, 69, 70).

Racial differences.

In the USPHS study (63), African-American males appeared to have less risk of DILI than white males, but there was no difference for women of any race. Asian males appeared to have nearly double the rate of probable isoniazid hepatitis than white males and nearly 14 times that of black males. In the Seattle–King County study, there was a nonsignificant trend toward higher hepatotoxicity in white individuals, without other significant racial differences (66). The Memphis, Tennessee, study found no associations among racial groups or demographic subgroups and hepatotoxicity (68). There do not appear to be consistent racially based risks for high-grade hepatotoxocity.

Sex.

There is currently no clear evidence to point to an overall sex-related difference in the incidence of hepatotoxicity. Pregnant women in the third trimester and in the first 3 months of the postpartum period may be at higher risk for the development of hepatitis (71). In the USPHS study, there was no overall difference between women and men in rates of probable isoniazid hepatotoxicity (63). The Seattle–King County study (66) found a nonsignificant trend toward higher isoniazid-related hepatotoxicity in women compared with men, although the incidence of severe hepatotoxicity was relatively low in both men and women. The Memphis and San Diego studies found no significant associations between sex and hepatotoxicity (67, 68).

Deaths.

Several retrospective studies and reviews with methodologic limitations suggest that the severity of isoniazid-induced hepatotoxicity, when it does occur, may be worse in women. In the USPHS study (63), there were 8 deaths among 13,838 enrolled subjects (0.57 per 1,000 treated), 5 of which were in African-American women, with 7 of 8 deaths occurring in Baltimore, Maryland. Most of those who died had potential cofactors for hepatotoxicity, including severe alcoholism or ingestion of other hepatotoxic drugs. Another cofactor may have been involved in the observed clustering, as a subsequent review of death certificates showed a surge in cirrhosis-related deaths in Baltimore and surrounding counties during the time period of this study (72). In the IUAT study, there were three deaths with a death rate of 0.14 of 1,000 treated (64). A review of probable and possible isoniazid hepatitis cases from 1970 to 1992 suggested a case fatality rate of 0.042 per 1,000 persons beginning therapy and a rate of no greater than 0.07 per 1,000 persons completing therapy (69). This review included some of the previously discussed fatalities. There were 62 probable and possible isoniazid hepatitis deaths, 50 (81%) of the patients were female, and 49 (79%) were non-Hispanic black or Hispanic. Although most individuals who died were older than 35 years, a surprising 31% were younger. Although these are numerator data only, they indicate that no age group is free of risk. Another review of fatal cases also suggested that women may be at higher risk for death from isoniazid-related hepatitis (70).

Cofactors.

In the USPHS surveillance study (63), alcohol consumption appeared to more than double the rate of probable isoniazid hepatitis, with daily consumption increasing the rate more than four times. Transaminase elevation may be, in some cases, related to chronic ethanol use. Hepatotoxicity during concomitant administration of other hepatotoxic drugs, such as acetaminophen (73), methotrexate (74), sulfasalazine (74), or carbamazepine (75), as well as others, has been reported.

HIV-infected individuals.

HIV-infected individuals appear to experience isoniazid-related hepatotoxicity in the same range as HIV-uninfected individuals (41, 76), although no direct comparisons through clinical trials have been done.

Hepatitis B.

Few studies have addressed the issue of isoniazid hepatotoxicity during LTBI in patients infected with hepatitis B. In a small study from Philadelphia, among Southeast-Asian individuals, the incidence of isoniazid hepatotoxicity was indistinguishable between chronic hepatitis B carriers and noncarriers (77). A second study of Vietnamese immigrants treated for LTBI with isoniazid in Iowa and Illinois distinguished between hepatitis B carriers with and without hepatitis B “e” antigen (HBeAg), a marker of active hepatitis B viral replication and related liver inflammation. Three of 21 (14%) individuals with HBeAg experienced symptomatic transaminase elevation of more than five times the ULN while taking isoniazid, whereas none of the 121 without HBeAg did, nearly an eightfold increased risk (78). Although additional data are needed, these studies suggest that active, but not quiescent, hepatitis may be a risk factor for increased incidence of isoniazid hepatotoxicity.

Hepatitis C.

Two studies showed no independent isoniazid hepatotoxicity risk associated with hepatitis C infection. In Baltimore, Maryland, a cohort of 146 tuberculin skin test–positive injection-drug users, 95% of whom were infected with hepatitis C, with baseline serum transaminase concentrations less than three times the ULN, and 25% of whom were HIV infected, received isoniazid for LTBI (79). Observed with monthly blood tests, 32 patients (22%) had increased transaminase concentrations to more than five times the ULN. Abnormal results were associated with alcohol use, but not with race, age, chronic hepatitis B infection, or HIV infection. Both the rate of hepatitis and the rate of isoniazid discontinuation were within the historical range for populations with a low prevalence of hepatitis C infection (10 to 22% and 0.1 to 10%, respectively). A second study in Spain (36) found that only excessive alcohol consumption and a high baseline ALT concentration were independently associated with isoniazid hepatotoxicity. The presence of hepatitis C virus (HCV) antibody was associated with hepatotoxicity only on univariate analysis in this study.

Elevated baseline transaminases.

The Tennessee retrospective study found that a baseline AST greater than the ULN was a risk factor for developing transaminase elevation greater than five times the ULN (68), as did another study among intravenous drug users (36).

Other factors increasing frequency or severity of hepatotoxicity.

Concomitant treatment with rifampin, malnutrition, prior isoniazid-related hepatotoxicity, and continued use of isoniazid while symptomatic have been described to contribute to higher-grade isoniazid hepatotoxicity (54).

Rifampin

Rifampin, and similarly rifapentine, may occasionally cause dose- dependent interference with bilirubin uptake, resulting in subclinical, unconjugated hyperbilirubinemia or jaundice without hepatocellular damage. This may be transient and occur early in treatment or in some individuals with preexisting liver disease (8083). Rifampin occasionally can cause hepatocellular injury and potentiate hepatotoxicities of other anti-TB medications (84, 85). In a study of patients with brucellosis treated with the combination of rifampin and minocycline, rifampin-attributed ALT increases of at least 250 IU/L were seen in approximately 5% of patients (86). In two small series of patients with primary biliary cirrhosis, in whom baseline transaminases were significantly elevated, clinically significant hepatitis was attributed to rifampin in 7.3 and 12.5% of patients (87, 88).

Mechanisms of hepatotoxicity.

Conjugated hyperbilirubinemia probably is caused by rifampin inhibiting the major bile salt exporter pump (89). Asymptomatic elevated bilirubin may also result from dose-dependent competition with bilirubin for clearance at the sinusoidal membrane or from impeded secretion at the canalicular level (4, 80, 81).

Rare hepatocellular injury appears to be a hypersensitivity reaction, and it may be more common with large, intermittent doses (80). Hypersensitivity reactions have been reported in combination with renal dysfunction, hemolytic anemia, or “flulike syndrome” (90, 91).

Drug interactions.

Rifampin activates hepatotocyte pregnane X receptors, leading to induction of cytochromes. Rifampin also induces uridine diphosphate-glucuronosyl-transferases and P-glycoprotein transport, which are involved in the metabolism of other drugs (9294). Rifampin interacts with numerous drugs metabolized by these and other hepatic enzymes, including warfarin, prednisone, digitoxin, quinidine, ketoconazole, itraconazole, propranolol, clofibrate, sulfonylureas, phenytoin, HIV protease inhibitors, and HIV nonnucleoside reverse transcriptase inhibitors (95).

Clinical characteristics of hepatotoxicity.

Cholestasis may be insidious. Idiosyncratic hypersensitivity reaction to rifampin, manifested as anorexia, nausea, vomiting, malaise, fever, mildly elevated ALT, and elevated bilirubin, usually occurs in the first month of treatment initiation (24, 80, 91, 96).

Overall hepatotoxicity.

Four published TB-related studies have assessed rifampin alone for treatment of LTBI. In a study by the Hong Kong Chest Service, transaminase elevations above the ULN were more common among patients receiving isoniazid-containing regimens than they were among the 77 of 172 patients treated with rifampin alone who had follow-up liver enzyme analyses (85). There was no significant difference between the geometric means of serum ALT for the placebo and rifampin groups. In the second study (97), none of the 49 individuals, 20% of whom used alcohol and 8% of whom used injection drugs, treated with rifampin for 6 months had symptomatic liver injury. There was no assessment for asymptomatic transaminase elevations. Among 157 adolescents treated with rifampin, 4 (2.5%) developed ALT elevations at least two times the ULN, for which treatment was permanently discontinued in one (98). A randomized study of isoniazid versus rifampin for treatment of LTBI in Montreal, Canada (84), found that, among 53 patients who completed 80% of a 4-month course of rifampin for LTBI, none experienced significant transaminase elevation. The apparent low rate of hepatotoxicity observed in these limited studies awaits confirmation in larger prospective studies.

Isoniazid and Rifampin

A Canadian study found that rates of hepatitis were similar for patients treated with intermittent isoniazid and rifampin compared with historical control subjects receiving daily isoniazid for 12 months (99). The rate of symptomatic hepatitis with the combination of isoniazid and rifampin has been estimated at 2.55% in a meta-analysis that included patients with TB disease, a higher incidence than in regimens containing one or the other drug (100).

Pyrazinamide

Pyrazinamide has been used with rifampin, ethambutol, or a fluoroquinolone for treatment of LTBI. Transaminase elevation more than four times the ULN was seen in 7 of 12 (58%) LTBI cases treated with pyrazinamide and ethambutol (42). Three of 17 (18%) patients prescribed levofloxacin and pyrazinamide for treatment of LTBI after exposure to MDR TB developed transaminase elevation more than four times the ULN (43). Nine of 22 (41%) patients treated with ofloxacin and pyrazinamide developed transaminase elevation of at least five times the ULN (44). Because these fluoroquinolones and ethambutol alone rarely cause hepatotoxicity, pyrazinamide is believed to be the offending agent in most cases of hepatotoxicity associated with these regimens.

Metabolism.

The half-life (t1/2) of pyrazinamide is notably longer than that of either isoniazid or rifampin, approximately 10 hours (46). In patients with preexisting hepatic disease, t1/2 is increased to 15 hours (101). Pyrazinamide, a nicotinic acid derivative, is de-amidated to pyrazinoic acid in the liver and subsequently metabolized to 5-hydroxy-pyrazinoic acid by xanthine oxidase (101), aldehyde oxidase (102), and xanthine dehydrogenase (103, 104). In addition, 5-hydroxy-pyrazinamide may be generated during metabolism (105). The kidneys clear metabolites of pyrazinamide, requiring intermittent dosing in patients with renal insufficiency (106).

Mechanism of injury.

Pyrazinamide may exhibit both dose-dependent and idiosyncratic hepatotoxicity. Several decades ago, daily doses of pyrazinamide at 40 to 50 mg/kg commonly caused hepatotoxicity, and a relationship to dose was noted (11). Pyrazinamide alters nicotinamide acetyl dehydrogenase levels in rat liver (107), which might result in generation of free radical species. There may be shared mechanisms of injury for isoniazid and pyrazinamide, because there is some similarity in molecular structure. Patients who previously had hepatotoxic reactions with isoniazid have had more severe reactions with rifampin and pyrazinamide given for LTBI (108). Pyrazinamide may induce hypersensitivity reactions with eosinophilia and liver injury (108) or granulomatous hepatitis (109).

Drug interactions.

Allopurinol alone or with pyrazinamide can be hepatotoxic (4, 110). Allopurinol inhibits xanthine oxidase, which metabolizes pyrazinamide, decreasing its clearance (111).

Rifampin and Pyrazinamide

The 2-month regimen of rifampin and pyrazinamide (RZ) is no longer recommended due to its hepatotoxicity (65, 108, 112).

HIV population.

Several studies in HIV-infected patients suggested RZ had either less or equal hepatotoxicity to isoniazid. A multicenter international trial reported less life-threatening and treatment-limiting hepatotoxicity among the study subjects taking RZ in comparison to subjects taking 12 months of isoniazid (113), and there were no differences in the incidence of significant AST elevations (114). Twice-weekly RZ was as well tolerated as isoniazid in two studies in Haiti and Zambia (115, 116). Two RZ-related deaths were reported among HIV-infected individuals in Centers for Disease Control and Prevention (CDC) retrospective surveillance. The regimen is no longer recommended in this population (65).

Non-HIV population.

Pilot studies showed higher transaminase elevations among individuals treated with RZ (117119), but a small pediatric study in Germany did not (120). In a study of 168 largely male jail inmates treated with RZ (121), most tolerated the regimen well, but two (1.2%) had increases of serum liver enzymes at least five times the ULN. Among 589 patients treated with either RZ or isoniazid, 7.8% of RZ patients had high-grade transaminase elevation versus 1% of those treated with 6 months of isoniazid (122). In North Carolina, 7.3% of 110 adults treated with RZ developed significant transaminase elevation, whereas none of the 114 treated with isoniazid did (19). In an observational study (123) of 1,210 jail inmates and homeless persons, all treated with RZ, 5.8% experienced significant transaminase elevation, and 2.5% had treatment discontinued because of liver injury. In contrast, in a retrospective study of 589 inmates in Maryland who received RZ twice weekly and had serum transaminases measured periodically, only one patient (0.17%) developed significant transaminase elevation (124). Two additional retrospective reviews (125, 126) found that RZ caused severe hepatotoxicity more often than did isoniazid.

A retrospective CDC surveillance study of patients treated with RZ found ALT elevations of at least five times the ULN in 26.4 of 1,000 treatment initiations. Hospitalization and death rates for these patients were 3 and 0.9 per 1,000 treatment initiations, respectively, substantially higher than the analogous rates estimated for isoniazid-treated patients: 0.1 to 0.2 and 0 to 0.3 per 1,000 treated, respectively (65).

In summary, most of these studies demonstrated an unacceptable rate of moderate or severe hepatotoxicity with daily RZ. The overall rate of liver injury associated with RZ was 7.2% and the rate of grade 3 or 4 liver injury was 5.6%. The RZ hepatotoxicity rates for HIV-uninfected patients may be greater than those for HIV-infected patients (125), but the reasons for this disparity are undetermined. The CDC and American Thoracic Society (ATS) have recommended that RZ should not be offered in general for treatment of LTBI (65).

Rifabutin

At the usual doses (150–300 mg/day), hepatotoxicity is uncommon. There is less induction of hepatic microsomal enzymes than with rifampin (127). Elevated transaminases have been reported with high-dose (600 mg/day) rifabutin treatment in combination with macrolides (128). In two studies of rifabutin for primary prophylaxis of Mycobacterium avium complex (MAC) in patients with AIDS, approximately 3 to 6.4% experienced grade 3 or higher AST elevations (129, 130). In patients with AIDS with disseminated MAC treated with rifabutin and a macrolide-containing regimen, hepatotoxicity occurred in approximately 8% (129).

Ethambutol

There has been one report of ethambutol-related liver cholestatic jaundice, with unclear circumstances (131).

Fluoroquinolones

Some fluoroquinolones (ciprofloxacin and moxifloxacin) are metabolized, in part, by the liver, whereas others (gatifloxacin, levofloxacin, ofloxacin) are largely excreted unchanged by the kidneys. Reversible transaminase elevation among the fluoroquinolones may occur in up to 2 to 3% of cases (132, 133). Severe hepatocellular injury and cholestasis have been reported to occur in less than 1% of all fluoroquinolone recipients, excluding trovafloxacin, which was withdrawn due to its hepatotoxicity (4, 134137). Clinically significant hepatotoxicity has been reported with ciprofloxacin, trovafloxacin, norfloxacin, ofloxacin, enoxacin, levofloxacin, and gatifloxacin, with large population denominators (138, 139). Direct comparisons of rates of clinically significant hepatotoxicity are not available. Among the newer fluoroquinolones, moxifloxacin-related transaminase elevation of at least 1.5 times the ULN has been reported in 0.9% of cases (140). For levofloxacin, the rate of severe hepatotoxicity was reported to be less than 1 per 1,000,000 (139). The mechanism of fluoroquinolone hepatotoxicity is believed to be a hypersensitivity reaction, often manifested by eosinophilia (138). Regarding hepatoxicity among contacts of MDR-TB cases treated with a fluoroquinolone and pyrazinamide, the causative agent has generally been assumed to be the latter (4244, 141).

The use of multiple regimens, vastly different study populations, varying definitions of hepatotoxicity, and different monitoring and reporting practices make it difficult to reach definitive conclusions regarding risks of individual regimens. Overall, the risk of TB DILI in these diverse studies ranges from 5 to as high as 33%.

Age over 35

Several studies suggest that increasing age is a risk factor for TB DILI, but often statistical significance was not achieved or hepatotoxicity was not treatment limiting (45, 142147). One study reported a TB DILI rate ranging from 2 to 8% as age increased, with an average of 5% (147). Other studies have reported that hepatotoxicity ranges from 22 to 33% in those older than 35 years, compared with 8 to 17% in those younger than 35 years (13, 45).

Children

In a retrospective study, severe TB DILI was diagnosed in 8% of pediatric patients, and was associated with age younger than 5 years, extrapulmonary TB, and use of pyrazinamide (148). In another study of children with a mean age of 4.5 years treated with isoniazid and rifampin, 82% experienced an ALT elevation greater than 100 IU/L, and more than 40% had symptomatic hepatitis with jaundice (149). In a study of South Indian patients with TB of all ages, 16 to 39% of children with tuberculous meningitis developed hepatitis “nearly always with jaundice.” These rates were substantially more than the 2 to 8% seen in the multiage cohorts with pulmonary or spinal TB (150). There are some data suggesting that doses of isoniazid greater than 15 to 20 mg/kg may be associated with a greater risk of hepatotoxicity (149, 151).

Sex

For women, several studies report increased risk of hepatotoxicity (142, 144, 145, 152, 153), but this was not always treatment limiting (146), or did not achieve statistical significance (152, 153). One study did show a four times higher risk of treatment-limiting hepatotoxicity in women, but with an overall incidence of only 2% (144). Two other studies showed no increased risk in women (63, 146).

Cofactors

Several studies have indicated that alcohol use was a significant predictor of TB DILI (31, 63, 147, 154, 155), whereas two studies found no association (144, 146).

Abnormal Baseline Transaminases

One study found an increased risk of hepatotoxicity during treatment of TB disease in individuals with abnormal baseline transaminases (35).

Acetylator Status

When acetylation rate has been determined by phenotypic assays, slow acetylators have experienced more hepatotoxicity in some studies (31, 58, 147, 150), but not in others (156158). Genotypic assays for acetylation class might improve the precision of future studies. One such study found that slow acetylators experienced more hepatotoxicity (26 vs. 11%) and more severe TB DILI than did fast acetylators (45).

Other Factors

Malnutrition or hypoalbuminemia was associated with TB DILI in several studies from India (147, 159161). The presence of HLA-DQB1*0201 is an independent risk factor for the development of TB DILI (161). Gene polymorphisms at loci of genes coding for cytochrome P450 2E1 and for glutathione S-transferase have also been associated with hepatotoxicity (45, 162). Extensive TB disease itself may be a risk factor for TB DILI, although confounding factors are impossible to exclude (142, 147). Liver transplant patients with TB appear to have a high rate of hepatotoxicity, with five of six treated patients developing this complication, confirmed by liver biopsy, and three of six suffering graft rejection (163).

Regimen

In a meta-analysis, the presence of rifampin in a multidrug treatment regimen increased the incidence of significant hepatotoxicity for adults from 1.6 to 2.55% and in children from 1.0 to 6.9% (100). The influence of pyrazinamide on TB DILI is ambiguous; some studies indicate little to no increased rate of hepatotoxicity (150, 164166), whereas others point to it as a contributor to increased incidence or severity of hepatotoxicity (143, 145, 146, 167), although dosing variations and patient selection biases may have contributed to these results.

HIV-infected Individuals

Limited data about TB DILI in HIV-infected patients come from observational studies or treatment trials, generally before the advent of HAART. A retrospective review of TB-AIDS cases in San Francisco from 1991 to 1998 showed a 4.8% rate of treatment alteration because of hepatitis (168). In a Western European clinical trial enrolling patients with TB-AIDS from 1989 to 1994, many who used intravenous drugs, 13 to 15% of patients had transaminase increases of at least three times the ULN in the first 2 months (169). Hepatoxicity was attributed to isoniazid in 55% of those with hepatitis.

In a U.S. multicenter trial from 1993 through 1997, patients with TB-AIDS treated with regimens containing isoniazid, rifampin, and pyrazinamide had an overall 4.4% rate of clinically significant or treatment-limiting hepatotoxicity (170). Injected drugs were used by 36% of these patients, and the median CD4+ T-cell count was 70/μl. In a retrospective review of TB disease treatment for HIV-infected patients in six U.S. cities from 1989 to 2000, increases of transaminases to 5 or 10 times the ULN were recorded for 13 and 5% of patients, respectively. Jaundice attributed to TB treatment was reported in 2% of patients (171).

During a prospective study in Haiti from 1990 to 1994 (172), increases in ALT of at least three times the ULN at 8 weeks were found in 12% of HIV-positive and in 9% of HIV-negative patients, and elevated bilirubin in 7 and 5% of patients, but there were no related interruptions in therapy.

In contrast, from a study of HIV, hepatitis C, and TB treatment (173), HIV infection independently increased the risk fourfold of serum transaminase increase to 120 IU/L or of total bilirubin to at least 1.5 mg/dl. Approximately 27% of HIV-infected individuals developed hepatotoxicity, compared with 12% among HIV-uninfected individuals. Nearly 80% of the patients in this study had a history of alcohol abuse, although random testing did not reveal active drinking, patients had not consumed alcohol in the 10 days before study entry, and all had normal baseline hepatic transaminases. The hepatotoxicity of antiretroviral drugs was not factored into the analysis (173).

In summary, definitions of hepatotoxicity and methodology varied among the studies, and most studies lacked HIV-negative control groups. Increases in serum transaminases or hepatitis were reported for 4 to 27% of patients, and increased bilirubin or jaundice in 0 to 7%. More data are needed in patients treated with HAART. The overall influence of HIV infection alone on DILI during treatment of TB disease is difficult to assess, but appears to be slight, with the exception of one study, where other confounding causes of hepatotoxicity, such as injection drug use, alcoholism, HAART, and viral hepatitis, were present.

Hepatitis B

Several studies from Asia have addressed DILI during treatment of TB disease in patients with hepatitis B infection. In Taiwan, 42 (2.4%) of 1,783 patients with TB treated with isoniazid, rifampin, and ethambutol had symptomatic hepatitis. Fifteen were hepatitis B carriers (had hepatitis B surface antigen), and 7 of 15 died of hepatic failure. Of the other 27 patients with symptomatic hepatitis who were not hepatitis B carriers, one died of hepatic failure (174). The severity of hepatotoxicity appears to have been increased in the hepatitis B carrier population.

Also in Taiwan, hepatitis B carriers with TB who received isoniazid, rifampin, pyrazinamide, and ethambutol had a hepatotoxicity rate of 29%, similar to the 26% experienced by hepatitis B–seronegative individuals (157). Patients were excluded if alcohol ingestion exceeded 60 g/day or if baseline serum transaminase concentrations were greater than the ULN.

In a study from Hong Kong (175), which excluded alcoholic and nonviral liver diseases, 16% of patients with TB with hepatitis B surface antigen developed symptomatic hepatitis compared with 4.7% in those without hepatitis B infection. Patients who had hepatitis B surface antigen also had more severe liver injury and were more likely to have a permanent treatment discontinuation, 4.7 compared with 2.5%.

A retrospective case-control study from Seoul, Korea, of 110 patients with hepatitis B surface antigen and normal pretreatment transaminases found a trend toward transminase elevations of at least five times the ULN more frequently in the hepatitis B carrier group than in the control subjects (8 vs. 2%, p = 0.05). However, isoniazid and rifampin were successfully reintroduced in five of the nine carriers (176).

In summary, notable variations in study designs and the potential for confounding reasons preclude firm conclusions about the contribution of hepatitis B carriage alone to the incidence of liver injury for patients being treated for TB disease. Two of these four studies (175, 176) indicate that there may be increased incidence of TB DILI in hepatitis B carriers, whereas one does not (157). Two studies (174, 175) suggest that hepatitis B carriers may incur more severe hepatic disease from treatment-associated liver injury, and the extent of underlying liver disease could be a determinant. These studies did not stratify patients according to evidence of active hepatitis B viral replication, such as HBeAg or hepatitis B viral DNA. Additional studies are needed, but the limited data leave sufficient concern that hepatitis B may be a risk factor for more frequent or severe hepatotoxicity during treatment of TB disease.

Hepatitis C

One study (173) has evaluated the impact of HCV infection on DILI during treatment for TB disease among 128 inpatients in Florida. All received at least 5 days of isoniazid, rifampin or rifabutin, or pyrazinamide, and had not received alcohol or drugs of abuse for at least 10 days before starting anti-TB therapy. Approximately 30% of hepatitis C–infected individuals developed hepatotoxicity compared with 11% among hepatitis C–uninfected individuals. Hepatitis C was an independent risk factor for the development of hepatotoxicity, elevating the risk fivefold of transaminase elevation of at least 120 U/L, or of serum bilirubin of at least 1.5 mg/dl. Coinfection with both hepatitis C and HIV elevated the risk of hepatotoxicity more than 14-fold.

DILI with Second-line Anti-TB Agents

Hepatotoxicity has been recognized to occur in about 2% of patients treated with ethionomide (177, 178) or prothionamide (179, 180), and in 0.3% of patients treated with para-aminosalicylic acid (181). Cycloserine does not appear to be associated with hepatotoxicity, but should be used with caution in patients at risk for alcohol withdrawal seizures (106).

Program Infrastructure

Standardized approaches to developing safe treatment of LTBI and TB disease should be implemented in an effort to prevent TB DILI. Optimal care requires the following:

  1. Clear and recurring communications with patients in the preferred language

  2. Accurate medical evaluation, treatment, and monitoring

  3. Convenient access to care and rapid responses to suspected drug adverse events

Provider Education and Resources

  1. TB DILI policies and procedures should be included in clinic manuals and in staff training.

  2. Other health providers should be made aware of TB diagnosis and treatment, as allowed.

  3. Providers without TB treatment experience or infrastructure should consider referral to a specialized clinic.

Pretreatment Clinical Evaluation

  1. A standardized history form is recommended, which includes risk factors for hepatotoxicity.

  2. The physical examination should include evaluation for signs of liver disease, such as liver tenderness, hepatosplenomegaly, jaundice, caput medusa, spider angiomata, ascites, and edema.

  3. Previous laboratory values should be reviewed when available.

  4. Screening for viral hepatitis should be considered for individuals who inject drugs; were born in endemic areas of Asia, Africa, the Pacific Islands, Eastern Europe, or the Amazon Basin; are HIV infected; may have had sexual or household contact with chronically infected individuals; may have had occupational exposure to infected blood; are chronic hemodialysis patients; are recipients of clotting factors before 1987; have undiagnosed liver disease; or are recipients of blood or solid organ transplants before 1992. Infants born to infected mothers should also be considered for screening.

  5. Voluntary HIV counseling and testing are recommended for all patients with TB disease.

Patient Education

  1. Printed instructions should include clinic telephone numbers, include explicit instructions for after-hours care, and utilize patient's preferred language at a readable level.

  2. Patients should be categorically told to immediately stop medications for nausea, vomiting, abdominal discomfort, or unexplained fatigue and to contact the clinic for further evaluation.

  3. Patients should attend clinic follow-up visits for monitoring and reinforcement of education.

  4. Patients should be warned about concomitant alcohol and hepatotoxic over-the-counter, and alternative and prescription medication use.

  5. 5.Patients should inform their health care providers of anti-TB medications prescribed.

Medication Administration and Pharmacy

  1. Limiting dispensed doses to 1-month supplies constitutes a partial safeguard against continued drug ingestion when adverse effects are experienced.

  2. The pharmacist should reinforce relevant patient education.

  3. 3.Medication package labels, in the patient's preferred language, warning against ingestion if specific hepatitis symptoms are present may be useful.

Treatment of LTBI
Patient and regimen selection.

The clinician and patient decide on treatment of LTBI based on the benefits of treatment relative to its risks (Figure 1) (41).

  1. Isoniazid taken for 9 months remains the preferred regimen.

  2. Rifampin is an option for patients who may not tolerate isoniazid, but potential drug interactions should be considered.

  3. Because isoniazid with rifampin is more hepatotoxic than either alone (100), this combination should be used with caution in patients at risk for hepatotoxicity.

  4. For those with ALT elevation more than 2.5 to 3 times the ULN, chronic alcohol consumption, or severe liver disease manifested by low albumin and coagulopathy or encephalopathy, the risks of LTBI may outweigh benefits. If LTBI treatment is undertaken, close monitoring is indicated.

  5. RZ is no longer generally recommended for treatment of LTBI (65).

Clinical monitoring (Figure 2).

  1. Face-to-face clinical assessments are the cornerstone of clinical monitoring for treatment adherence and adverse effects.

  2. Provider checklists for questioning patients should include adverse effects of anti-TB drugs and use of alcohol and other potentially hepatotoxic drugs.

  3. The plan for clinical and/or biochemical monitoring should be explicit in clinic records.

Baseline laboratory testing and monitoring (Figure 2).

  1. Baseline blood tests are generally not recommended for healthy patients treated with isoniazid or rifampin.

  2. Baseline and follow-up serum ALT and bilirubin are recommended for patients with a possible liver disorder; those with a history of chronic liver disease (e.g., chronic hepatitis B and C, alcoholic hepatitis, and cirrhosis), patients with chronic use of alcohol, those with HIV infection treated with HAART, pregnant women, and those who are up to 3 months postpartum.

  3. Baseline laboratory testing should be considered individually for patients receiving other medications and for those with chronic medical conditions (41).

  4. Some experts recommend that healthy individuals older than 35 years treated with isoniazid or isoniazid with rifampin have baseline and scheduled monitoring of ALT. Monitoring schedules in such cases may be monthly; every other month; or at 1, 3, and 6 months in those taking a 9-month regimen (68), depending on the perceived hepatotoxicity risk, effectiveness of patient education, and the stability of ALT.

  5. ALT is preferred for detecting and tracking hepatocellular injury in those who develop symptoms of hepatotoxicity.

  6. Measurements of AST, bilirubin, and alkaline phosphatase are adjunctive for monitoring chronic liver disease, cholestasis, or severe hepatocellular injury.

  7. The ULN used should be that of the laboratory performing the assay.

  8. Optimally, reference limits for enzymes should be adjusted for age in children and in adults older than 60, and for sex in adults, if available (13, 14).

  9. Hepatitis B surface antigen–seropositive individuals with elevated ALT should have HBeAg testing. If positive, rifampin may be preferred over isoniazid. A hepatologist should be consulted regarding further testing and possible pretreatment in individuals with an ALT at least two times the ULN, and who are HBeAg seropositive (182). In HBeAg-seropositive individuals, clinical and ALT monitoring should occur every 2 to 4 weeks.

  10. Patients with baseline transaminases more than three times the ULN should have ALT retested along with bilirubin, as well as screening for viral or other causes of hepatitis, including alcohol and hepatotoxic drugs. The decision to treat LTBI, or more likely to defer, should be carefully made on a case-by-case basis, weighing the risk of progression to TB disease against the risk of isoniazid- or rifampin-related DILI. Factors influencing the latter include degree of baseline ALT elevation, alcohol consumption, age, and evidence of active replication of hepatitis virus. If treatment is started, some experts recommend measuring serum transaminases and bilirubin concentrations every 2 to 4 weeks for the first 2 to 3 months, and as necessary. The international normalized ratio (INR) may be followed periodically as well in patients with severe hepatic impairment.

  11. Some experts recommend monitoring transaminases in individuals treated with a combination of pyrazinamide and a fluoroquinolone or ethambutol for contact with a patient with MDR TB.

Interventions for hepatotoxicity (Figure 2).

  1. Isoniazid should be withheld if ALT is at least three times the ULN when jaundice and/or hepatitis symptoms are reported, or if ALT is at least five times the ULN in the absence of symptoms (41).

  2. A rapid increase in ALT may be an indication for more frequent monitoring, every 2 weeks instead of monthly, particularly if one of these treatment-limiting ALT thresholds is being approached, or if the patient has previously identified risk factors for hepatotoxicity.

  3. For the few patients who may begin isoniazid LTBI treatment with a baseline ALT more than three times the ULN, some experts recommend, in the absence of adequate clinical data, that treatment should be discontinued if there is more than a two- to threefold increase above baseline or if there is a mental status change, jaundice, or significant increase in bilirubin or INR.

Screening for other causes of hepatitis.

  1. Viral hepatitis and concomitant use of hepatotoxic drugs of any type should be excluded.

  2. 2.Screening tests for viral hepatitis should include IgM anti–hepatitis A virus, hepatitis B surface Ag, IgM anti–hepatitis B core, and anti-HCV antibody.

  3. In unusual or suggestive cases, the following tests may be considered: (1) anti–hepatitis E for recent residents of or travelers to endemic areas in developing countries, such as in Asia, North Africa, and Mexico; (2) anti-HDV antibodies (IgG and IgM) for injection drug users with evidence of hepatitis B (HBsAg); (3) HCV RNA to assess replication status in HCV antibody–positive cases or to exclude HCV antibody–negative cases (e.g., those with marked immune suppression or early infection); (4) heterophile Epstein-Barr virus antibody; and (5) antibodies to cytomegalovirus and herpes simplex in immunosuppressed patients.

  4. In severe cases or in those in whom ALT did not recover with drug withdrawal, additional testing for autoimmune disease may also be considered: anti–nuclear antibody, anti–smooth muscle antibody, anti–liver-kidney microsomal antibody, and immunoglobulin profile (IgG, IgM, and IgA).

  5. Hepatology consultation is recommended for unusual or severe cases of hepatitis, particularly those who become sufficiently ill to require hospital admission or who may require liver transplantation.

Rechallenge.

  1. The risk of reintroducing of a TB medication could be hazardous and should be considered relative to its potential benefit.

  2. Rechallenge is considered when it is unclear which medication was the cause of symptoms or of transaminase increases.

  3. Rechallenge also may be considered if an increase in transaminase concentration did not reach the usual treatment-limiting threshold.

  4. Rechallenged patients who had reached a treatment-limiting threshold should have clinical and biochemical monitoring at 2- to 4-week intervals.

  5. Rechallenged patients should be told to stop medication in case of hepatitis symptoms.

Reporting of serious adverse events.

  1. Health care providers should report serious adverse effects, including hepatotoxicity, to the U.S. FDA's MedWatch program. Reporting may be by mail, telephone (1-800-FDA-1088), fax (1-800-FDA-0178), or at the Internet website (www.fda.gov/medwatch).

  2. Adverse effects of treating LTBI serious enough to entail hospital admission or death also should be reported to the CDC through local public health authorities or by calling 404-639-8401.

  3. These surveillance systems capture different data, and reporting to both is necessary.

Treatment of TB Disease
Regimen selection.

The crucial efficacy of isoniazid, and particularly rifampin, warrants their use and retention, if at all possible, even in the face of preexisting liver disease (106). Several regimens are recommended if baseline serum ALT is more than three times the ULN, and TB is not believed to be the cause (106):

  1. Treatment without pyrazinamide might utilize isoniazid and rifampin for 9 months with ethambutol until drug susceptibility testing of the M. tuberculosis isolate is completed.

  2. In patients with cirrhosis, rifampin and ethambutol, with levofloxacin, moxifloxacin, gatifloxacin, or cycloserine, for 12 to 18 months may be considered.

  3. For patients with encephalopathic liver disease, ethambutol combined with a fluoroquinolone, cycloserine, and capreomycin or aminoglycoside for 18 to 24 months may be an option. However, these regimens have not been tested systematically (106).

  4. Some providers avoid aminoglycosides in severe, unstable liver disease due to concerns about renal insufficiency, or bleeding from injected medication in patients with thrombocytopenia and/or coagulopathy.

Clinical monitoring.

  1. Face-to-face monthly assessments and patient education for adverse drug events are essential.

  2. Directly observed treatment (DOT) enhances treatment adherence and monitoring (106).

  3. The World Health Organization and the International Union Against Tuberculosis and Lung Disease (IUATLD) recommend only clinical monitoring in patients with TB in low-income countries (41, 183, 184).

Baseline testing and monitoring (Figure 3).

  1. Baseline measurements of serum transaminases, bilirubin, alkaline phosphatase, and creatinine, and a blood platelet count are recommended for all adults beginning treatment for TB disease.

  2. For patients with preexisting severe liver disease, some clinicians also recommend periodic measurement of prothrombin time and INR to assess hepatic synthetic function.

  3. Routine measurements during treatment are recommended when baseline abnormalities are present and for patients who chronically consume alcohol, take other potentially hepatotoxic medications, or who have viral hepatitis or history of liver disease, HIV infection, or prior TB DILI.

  4. In patients with abnormal baseline transaminases, the range of their prior fluctuations may be of assistance in interpreting results of biochemical monitoring of treatment.

  5. Some providers prefer to monitor ALT in women or older adults being treated for TB disease.

Interventions for hepatotoxicity.

  1. The first-line anti-TB drugs, especially rifampin, should not be discontinued for mild gastrointestinal complaints, which may be relatively frequent in the initial weeks of anti-TB treatment.

  2. If serum transaminase concentrations are more than five times the ULN (with or without symptoms) or more than three times the ULN with jaundice and/or hepatitis symptoms, then potentially hepatotoxic medications should be stopped immediately and the patient evaluated promptly.

  3. Serologic tests for hepatitis A, B, and C viruses should be obtained, and the patient should be evaluated for biliary disease, use of alcohol, and other hepatotoxic drugs.

  4. Some experts recommend interrupting treatment for lesser increases in patients with cirrhosis or encephalopathy.

  5. If indicated, until the specific cause of abnormalities can be determined, clinicians should treat with at least three anti-TB agents that are less likely to cause hepatotoxicity.

Rechallenge.

  1. After ALT returns to less than two times the ULN, rifampin may be restarted with or without ethambutol.

  2. After 3 to 7 days, isoniazid may be reintroduced, subsequently rechecking ALT.

  3. If symptoms recur or ALT increases, the last drug added should be stopped.

  4. For those who have experienced prolonged or severe hepatotoxicity, but tolerate reintroduction with rifampin and isoniazid, rechallenge with pyrazinamide may be hazardous. In this circumstance, pyrazinamide may be permanently discontinued, with treatment extended to 9 months. Although pyrazinamide can be reintroduced in some milder cases of hepatotoxicity (144), the benefit of a shorter treatment course likely does not outweigh the risk of severe hepatotoxicity from pyrazinamide rechallenge.

  1. Basic mechanisms of TB DILI. Further understanding is needed regarding mechanisms of drug injury, genetic variation of enzymes involved in TB drug metabolism and transport, potential hepatoprotective agents, and the influence of concomitant viral hepatitis.

  2. Program infrastructure and education modifications. Education and intervention studies to minimize the impact of TB DILI are needed.

  3. Regimen selection and other hepatotoxic medications. New, and less hepatotoxic, regimens will need safety and tolerability studies. Studies assessing the effect of hepatoprotective agents and of coadministered potentially hepatotoxic medications on the incidence and severity of TB DILI are needed.

  4. Monitoring. Studies are needed to demonstrate that ALT monitoring reduces the incidence or severity of TB DILI.

  5. Hepatotoxicity risk assessments. Additional studies are needed to assess hepatotoxicity in women and in those with viral hepatitis, including whether to treat chronic active hepatitis in selected patients before LTBI treatment.

  6. Medication administration and pharmacy. Routes of administration that could reduce hepatotoxicity should be developed for clinical trials.

Many unanswered questions remain regarding TB DILI in an aging population, in an increasingly complex medical environment, with evolving demographics for TB infection and where new treatments for TB are being developed. Understanding of the basic mechanisms and genetic factors associated with TB DILI is nascent. Such information should eventually allow identification of those most likely to suffer increased incidence and/or severity of DILI. The existing data are, in some instances, insufficient to come to strong conclusions regarding hepatotoxicity risks and monitoring. In the future, issues related to TB DILI will need to be reexamined as new data become available. Safe systems for treating patients, patient and staff education, appropriate selection of patients for treatment, careful regimen selection, and monitoring help minimize risks. The ability to adapt to a changing medical landscape will be crucial to continued safe and effective treatment for TB.

This statement was prepared by an ad hoc subcommittee of the ATS Assembly on Microbiology, Tuberculosis, and Pulmonary Infections.

1. Lee J, Boyer JL. Molecular alterations in hepatocyte transport. Semin Liver Dis 2000;20:373–384.
2. Hilsden RJ, Shaffer E. Liver structure and function. In: Thomson A, Shaffer E, editors. First principles of gastroenterology: the basis of disease and an approach to management, 4th ed. Edmonton, AB, Canada: Astra; 2000. pp. 462–564.
3. Benichou C. Criteria for drug-induced liver disorder: report of an international consensus meeting. J Hepatol 1990;11:272–276.
4. Chitturi S, Farrell G. Drug-induced liver disease. In: Schiff ER, Sorrell MF, Maddrey WC, editors. Schiff's diseases of the liver, 9th ed. Philadelphia: Lippincott, Williams & Wilkins; 2002. pp. 1059–1128.
5. Larrey D. Epidemiology and individual susceptibility to adverse drug reactions affecting the liver. Semin Liver Dis 2002;22:145–155.
6. Ostapowicz GM, Fontana R, Schiødt F, Larson A, Davern T, Steven Han H, McCashland T, Shakil A, Hay J, Hynan L, et al. Results of a prospective study of acute liver failure at 17 tertiary care centers in the United States. Ann Intern Med 2002;137:947–954.
7. American Society of Health-Systems Pharmacists. American Hospital Formulary Service (AHFS) drug information [CD-ROM]. Gerald K. McEvoy, ed. Marlborough, MA: Skyscape; 2005.
8. Carson JL, Strom BL, Duff A, Gupta A, Das K. Safety of nonsteroidal anti-inflammatory drugs with respect to acute liver disease. Arch Intern Med 1993;153:1331–1336.
9. Brown SJ, Desmond PV. Hepatotoxicity of antimicrobial agents. Semin Liver Dis 2002;22:157–167.
10. Kaplowitz N. Drug-induced liver injury. Clin Infect Dis 2004;38:S44–S48.
11. U.S. Public Health Service. Hepatic toxicity of pyrazinamide used with isoniazid in tuberculous patients. Am Rev Respir Dis 1969;59:13.
12. Kaplowitz N. Biochemical and cellular mechanisms of toxic liver injury. Semin Liver Dis 2002;22:137–144.
13. Dufour DR, Lott JA, Nolte FS, Gretch DR, Koff RS, Seeff LB. Diagnosis and monitoring of hepatic injury: I. Performance characteristics of laboratory tests. Clin Chem 2000;46:2027–2049.
14. Dufour DR, Lott JA, Nolte FS, Gretch DR, Koff RS, Seeff LB. Diagnosis and monitoring of hepatic injury: II. Recommendations for use of laboratory tests in screening, diagnosis, and monitoring. Clin Chem 2000;46:2050–2068.
15. American Gastroenterologic Association Clinical Practice Committee. AGA technical review on the evaluation of liver chemistry tests. Gastroenterology 2002;123:1367–1384.
16. Prati D, Taioli E, Zanella A, Della Torre E, Butelli S, Del Vecchio E, Vianello L, Zanuso F, Mozzi F, Milani S, et al. Updated definitions of healthy ranges for serum alanine aminotransferase levels. Ann Intern Med 2002;137:1–10.
17. Rosenzweig P, Miget N, Brohier S. Transaminase elevation on placebo during phase I trials: prevalence and significance. Br J Clin Pharmacol 1999;48:19–23.
18. Williams GM, Iatropoulos MJ. Alteration of liver cell function and proliferation: differentiation between adaptation and toxicity. Toxicol Pathol 2002;30:41–53.
19. McNeill L, Allen M, Estrada C, Cook P. Pyrazinamide and rifampin vs isoniazid for the treatment of latent tuberculosis: improved completion rates but more hepatotoxicity. Chest 2003;123:102–106.
20. Turktas H, Unsal M, Tulek N, Oruc O. Hepatotoxicity of antituberculosis therapy (rifampicin, isoniazid and pyrazinamide) or viral hepatitis. Tuber Lung Dis 1994;75:58–60.
21. Kumar A, Misra PK, Mehotra R, Govil YC, Rana GS. Hepatotoxicity of rifampin and isoniazid: is it all drug-induced hepatitis? Am Rev Respir Dis 1991;143:1350–1352.
22. Dielh AM. Cytokine regulation of liver injury and repair. Immunol Rev 2000;174:160–171.
23. Amacher D. Serum transaminase elevations as indicators of hepatic injury following the administration of drugs. Regul Toxicol Pharmacol 1998;27:119–130.
24. Kremer JM, Lee RG, Tolman KG. Liver histology in rheumatoid arthritis patients receiving long-term methotrexate therapy: a prospective study with baseline and sequential biopsy samples. Arthritis Rheum 1989;32:121–127.
25. Yu AS, Keeffe EB. Nonalcoholic fatty liver disease. Rev Gastroenterol Disord 2002;2:11–19.
26. Martin-Carbonero L, Nunez M, Gonzalez-Lahoz J, Soriano V. Incidence of liver injury after beginning antiretroviral therapy with efavirenz or nevirapine. HIV Clin Trials 2003;4:115–120.
27. Uberti-Foppa C, De Bona A, Morsica G, Galli L, Gallotta G, Boeri E, Lazzarin A. Pretreatment of chronic active hepatitis C in patients coinfected with HIV and hepatitis C virus reduces the hepatotoxicity associated with subsequent antiretroviral therapy. J Acquir Immune Defic Syndr 2003;33:146–152.
28. Langman G, Hall PM, Todd G. Role of non-alcoholic steatohepatitis in methotrexate-induced liver injury. J Gastroenterol Hepatol 2001;16: 1395–1401.
29. Herman JS, Easterbrook PJ. The metabolic toxicities of antiretroviral therapy. Int J STD AIDS 2001;12:555–562.
30. Farrell GC. Drugs and steatohepatitis. Semin Liver Dis 2002;22:185–194.
31. Gronhagen-Riska C, Hellstrom PE, Froseth B. Predisposing factors in hepatitis induced by isoniazid-rifampin treatment of tuberculosis. Am Rev Respir Dis 1978;118:461–466.
32. Tanaka E, Terada M, Misawa S. Cytochrome P450 2E1: its clinical and toxicological role. J Clin Pharm Ther 2000;25:165–175.
33. Lieber CS. Susceptibility to alcohol-related liver injury. Alcohol Alcohol Suppl 1994;2:315–326.
34. Kanathur N, Mathai MG, Byrd RP, Fields CL, Roy TM. Simvastatin-diltiazem drug interaction resulting in rhabdomyolysis and hepatitis. Tenn Med 2001;94:339–341.
35. Teleman MD, Chee CB, Earnest A, Wang YT. Hepatotoxicity of tuberculosis chemotherapy under general programme conditions in Singapore. Int J Tuberc Lung Dis 2002;6:699–705.
36. Fernandez-Villar A, Sopena B, Vazquez R, Ulloa F, Fluiters E, Mosteiro M, Martinez-Vazquez C, Pineiro L. Isoniazid hepatotoxicity among drug users: the role of hepatitis C. Clin Infect Dis 2003;36:293–298.
37. Stern JO, Robinson PA, Love J, Lanes S, Imperiale MS, Mayers DL. A comprehensive hepatic safety analysis of nevirapine in different populations of HIV infected patients. J Acquir Immune Defic Syndr 2003;34:S21–S33.
38. Massacesi C, Santini D, Rocchi MB, La Cesa A, Marcucci F, Vincenzi B, Delprete S, Tonini G, Bonsignori M. Raltitrexed-induced hepatotoxicity: multivariate analysis of predictive factors. Anticancer Drugs 2003;14:533–541.
39. Suzuki Y, Uehara R, Tajima C, Noguchi A, Ide M, Ichikawa Y, Mizushima Y. Elevation of serum hepatic aminotransferases during treatment of rheumatoid arthritis with low-dose methotrexate: risk factors and response to folic acid. Scand J Rheumatol 1999;28:273–281.
40. Schenker S, Martin RR, Hoyumpa AM. Antecedent liver disease and drug toxicity. J Hepatol 1999;31:1098–1105.
41. American Thoracic Society/Centers for Disease Control and Prevention. Targeted tuberculin testing and treatment of latent tuberculosis infection. Am J Respir Crit Care Med 2000;161:S221–S247.
42. Younossian AB, Rochat T, Ketterer JP, Wacker J, Janssens JP. High hepatotoxicity of pyrazinamide and ethambutol for treatment of latent tuberculosis. Eur Respir J 2005;26:462–464.
43. Papastavros T, Dolovich LR, Holbrook A, Whitehead L, Loeb M. Adverse events associated with pyrazinamide and levofloxacin in the treatment of latent multidrug-resistant tuberculosis. CMAJ 2002;167: 131–136.
44. Ridzon R, Meador J, Maxwell R, Higgins K, Weismuller P, Onorato IM. Asymptomatic hepatitis in persons who received alternative preventive therapy with pyrazinamide and ofloxacin. Clin Infect Dis 1997;24:1264–1265.
45. Huang YS, Chern HD, Su WJ, Wu JC, Lai SL, Yang SY, Chang FY, Lee SD. Polymorphism of the N-acetyltransferase 2 gene as a susceptibility risk factor for antituberculosis drug-induced hepatitis. Hepatology 2002;35:883–889.
46. Huang YS, Chern HD, Su WJ, Wu JC, Chang SC, Chiang CH, Chang FY, Lee SD. Cytochrome P450 2E1 genotype and the susceptibility to antituberculosis drug-induced hepatitis. Hepatology 2003;37:924–930.
47. Smith CA, Wadelius M, Gough AC, Harrison DJ, Wolf CR, Rane A. A simplified assay for the arylamine N-acetyltransferase 2 polymorphism validated by phenotyping with isoniazid. J Med Genet 1997;34: 758–760.
48. Mitchell JR, Thorgeirsson UP, Black M, Timbrell JA, Snodgrass WR, Potter WZ, Jollow HR, Keiser HR. Increased incidence of isoniazid hepatitis in rapid acetylators: possible relation to hydrazine metabolites. Clin Pharmacol Ther 1975;18:70–79.
49. Yamamoto T, Suou T, Hirayama C. Elevated serum aminotransferase induced by isoniazid in relation to isoniazid acetylator phenotype. Hepatology 1986;6:295–298.
50. Dickinson DS, Bailey WC, Hirschowitz BI, Soong SJ, Eidus L, Hodgkin MM. Risk factors for isoniazid (INH)-induced liver dysfunction. J Clin Gastroenterol 1981;3:271–279.
51. Gurumurthy P, Krishnamurthy MS, Nazareth O, Parthasarathy R, Sarma GR. Lack of relationship between hepatic toxicity and acetylator phenotype in three thousand South Indian patients during treatment with isoniazid for tuberculosis. Am Rev Respir Dis 1984;129: 58–61.
52. Attri S, Rana SV, Vaiphie K, Katyal R, Sodhi CP, Kanwar S, Singh K. Protective effect of N-acetylcysteine in isoniazid induced hepatic injury in growing rats. Indian J Exp Biol 2001;39:436–440.
53. Sodhi CP, Rana SV, Mehta SK, Vaiphei K, Attri S, Thakur S, Mehta S. Study of oxidative stress in isoniazid-induced hepatic injury in young rats with and without protein-energy malnutrition. J Biochem Toxicol 1996;11:139–146.
54. Mitchell JR, Zimmerman HJ, Ishak KG, Thorgeirsson UP, Timbrell JA, Snodgrass WR, Nelson SD. Isoniazid liver injury: clinical spectrum, pathology, and probable pathogenesis. Ann Intern Med 1976;84:181–192.
55. Desta Z, Soukhova NV, Flockhart DA. Inhibition of cytochrome P450 (CYP450) isoforms by isoniazid: potent inhibition of CYP2C19 and CYP3A. Antimicrob Agents Chemother 2001;45:382–392.
56. Tanaka E, Terada M, Misawa S. Cytochrome P450 2E1: its clinical and toxicological role. J Clin Pharm Ther 2000;25:165–175.
57. O'Shea D, Kim RB, Wilkinson GR. Modulation of CYP2E1 activity by isoniazid in rapid and slow N-acetylators. Br J Clin Pharmacol 1997;43:99–103.
58. Dickinson D, Bailey W, Hirschowitz B. The effect of acetylation status on isoniazid (INH) hepatitis. Am Rev Respir Dis 1977;115:395.
59. Sarma GR, Immanuel C, Kailasam S, Narayana AS, Venkatesan P. Rifampin-induced release of hydrazine from isoniazid: a possible cause of hepatitis during treatment of tuberculosis with regimens containing isoniazid and rifampin. Am Rev Respir Dis 1986;133:1072–1075.
60. Scharer L, Smith JP. Serum transaminase elevations and other hepatic abnormalities in patients receiving isoniazid. Ann Intern Med 1969; 71:1113–1120.
61. Ferebee S, Mount F. Tuberculosis morbidity in a controlled trial of the prophylactic use of isoniazid among household contacts. Am Rev Respir Dis 1962;85:490–510.
62. Garibaldi R, Drusin R, Ferebee S, Gregg M. Isoniazid-associated hepatitis: report of an outbreak. Am Rev Respir Dis 1972;106:357–365.
63. Kopanoff DE, Snider D, Caras G. Isoniazid related hepatitis: a U.S. Public Health Service cooperative surveillance study. Am Rev Respir Dis 1979;117:991–1001.
64. International Union Against Tuberculosis Committee on Prophylaxis. Efficacy of various durations of isoniazid preventive therapy for tuberculosis: five years of follow-up in the IUAT trial. Bull World Health Organ 1982;60:555–564.
65. Centers for Disease Control and Prevention, American Thoracic Society. Update: adverse event data and revised American Thoracic Society/CDC recommendations against the use of rifampin and pyrazinamide for treatment of latent tuberculosis infection—United States, 2003. MMWR Morb Mortal Wkly Rep 2003;52:735–739.
66. Nolan CM, Goldberg S, Buskin S. Hepatotoxicity associated with isoniazid preventive therapy: a 7-year survey from a public health tuberculosis clinic. JAMA 1999;281:1014–1018.
67. LoBue PA, Moser KS. Isoniazid- and rifampin-resistant tuberculosis in San Diego County, California, United States, 1993–2002. Int J Tuberc Lung Dis 2005;9:501–506.
68. Fountain FF, Tolley E, Chrisman CR, Self TH. Isoniazid hepatotoxicity associated with treatment of latent tuberculosis infection: a 7-year evaluation from a public health tuberculosis clinic. Chest 2005;128: 116–123.
69. Millard PS, Wilcosky T, Reade-Christopher S, Weher D. Isoniazid-related fatal hepatitis. West J Med 1996;164:486491.
70. Snider DE, Caras G. Isoniazid-associated hepatitis deaths: a review of available information. Am Rev Respir Dis 1992;145:494–497.
71. Franks A, Binkin N, Snider D, Rokaw W, Becker S. Isoniazid hepatitis among pregnant and postpartum Hispanic patients. Public Health Rep 1989;104:151–155.
72. Comstock G. Prevention of tuberculosis among tuberculin reactors: maximizing benefits, minimizing risks. JAMA 1986;256:2729–2730.
73. Crippin JS. Acetaminophen hepatotoxicity: potentiation by isoniazid. Am J Gastroenterol 1993;88:590–592.
74. Vanhoof J, Landewe S, Van Wijngaerden E, Geusens P. High incidence of hepatotoxicity of isoniazid treatment for tuberculosis chemoprophylaxis in patients with rheumatoid arthritis treated with methotrexate or sulfasalazine and anti-tumour necrosis factor inhibitors. Ann Rheum Dis 2003;62:1241–1242.
75. Berkowitz FE, Henderson SL, Fajman N, Schoen B, Naughton M. Acute liver failure caused by isoniazid in a child receiving carbamazepine. Int J Tuberc Lung Dis 1998;2:603–606.
76. Bucher HC, Griffith L, Guyatt G, Sudre P, Naef M, Sendi P, Battegay M. Isoniazid prophylaxis for tuberculosis in HIV infection: a meta-analysis of randomized controlled trials. AIDS 1999;13:501–507.
77. McGlynn KA, Lustbader ED, Sharrar RG, Murphy EC, London WT. Isoniazid prophylaxis in hepatitis B carriers. Am Rev Respir Dis 1986;134:666–668.
78. Patel PA, Voigt MD. Prevalence and interaction of hepatitis B and latent tuberculosis in Vietnamese immigrants to the United States. Am J Gastroenterol 2002;97:1198–1203.
79. Sadaphal P, Astemborski J, Graham NM, Sheely L, Bonds M, Madison A, Vlahov D, Thomas D, Sterling T. Isoniazid preventive therapy, hepatitis C virus infection, and hepatotoxicity among injection drug users infected with Mycobacterium tuberculosis. Clin Infect Dis 2001; 33:1687–1691.
80. Grosset J, Leventis S. Adverse effects of rifampin. Rev Infect Dis 1983;5:S440–S450.
81. Capelle P, Dhumeaux D, Mora M, Feldmann G, Berthelot P. Effect of rifampicin on liver function in man. Gut 1972;13:366–371.
82. Gabriel R. Rifampicin jaundice. BMJ 1971;3:182.
83. Erdil A, Kadayifci A, Ates Y, Bagci S, Uygun A, Dagalp K. Rifampicin test in the diagnosis of Gilbert's syndrome. Int J Clin Pract 2001;55: 81–83.
84. Menzies D, Dion MJ, Rabinovitch B, Mannix S, Brassard P, Schwartzman K. Treatment completion and costs of a randomized trial of rifampin for 4 months versus isoniazid for 9 months. Am J Respir Crit Care Med 2004;170:445–449.
85. Hong Kong Chest Service, Tuberculosis Research Centre, Madras, British Medical Research Council. A double-blind placebo-controlled clinical trial of three anti-tuberculosis chemoprophylaxis regimens in patients with silicosis in Hong Kong. Am Rev Respir Dis 1992;145: 36–41.
86. Cascio A, Scarlata F, Giordano S, Antinori S, Colomba C, Titone L. Treatment of human brucellosis with rifampin plus minocycline. J Chemother 2003;15:248–252.
87. Bachs L, Pares A, Elena M, Piera C, Rodes J. Effects of long-term rifampicin administration in primary biliary cirrhosis. Gastroenterology 1992;102:2077–2080.
88. Prince MI, Burt AD, Jones DE. Hepatitis and liver dysfunction with rifampicin therapy for pruritus in primary biliary cirrhosis. Gut 2002; 50:436–439.
89. Byrne JA, Strautnieks SS, Mieli-Vergani G, Higgins CF, Linton KJ, Thompson RJ. The human bile salt export pump: characterization of substrate specificity and identification of inhibitors. Gastroenterology 2002;123:1649–1658.
90. Covic A, Goldsmith D, Segall L, Stoicescu C, Lungu S, Volovat C, Covic M. Rifampicin-induced acute renal failure: a series of 60 patients. Nephrol Dial Transplant 1998;13:924–929.
91. Martinez E, Collazos J, Mayo J. Hypersensitivity reactions to rifampin. Medicine 1999;78:361–369.
92. Schuetz EG, Schinkel AH, Relling MV, Schuetz JD. P-glycoprotein: a major determinant of rifampicin-inducible expression of cytochrome P4503A in mice and humans. Proc Natl Acad Sci USA 1996;93:4001–4005.
93. Burk O, Koch I, Raucy J, Hustert E, Eichelbaum M, Brockmoller J, Zanger UM, Wojnowski L. The induction of cytochrome P450 3A5 (CYP3A5) in the human liver and intestine is mediated by the xenobiotic sensors pregnane X receptor (PXR) and constitutively activated receptor (CAR). J Biol Chem 2004;279:38379–38385.
94. Rae JM, Johnson MD, Lippman ME, Flockhart DA. Rifampin is a selective, pleiotropic inducer of drug metabolism genes in human hepatocytes: studies with cDNA and oligonucleotide expression arrays. J Pharmacol Exp Ther 2001;299:849–857.
95. Niemi M, Backman JT, Fromm MF, Neuvonen PJ, Kivisto KT. Pharmacokinetic interactions with rifampicin: clinical relevance. Clin Pharmacokinet 2003;42:819–850.
96. Scheuer PJ, Summerfield JA, Lal S, Sherlock S. Rifampicin hepatitis: a clinical and histological study. Lancet 1974;1:421–425.
97. Polesky A, Farber H, Gottlieb D, Park H, Levinson S, O'Connell J, McInnis B, Nieves R, Bernardo J. Rifampin preventive therapy for tuberculosis in Boston's homeless. Am J Respir Crit Care Med 1996; 154:1473–1477.
98. Villarino ME, Ridzon R, Weismuller PC, Elcock M, Maxwell RM, Meador J, Smith PJ, Carson ML, Geiter LJ. Rifampin preventive therapy for tuberculosis infection: experience with 157 adolescents. Am J Respir Crit Care Med 1997;155:1735–1738.
99. McNab BD, Marciniuk DD, Alvi RA, Tan L, Hoeppner VH. Twice-weekly isoniazid and rifampin treatment of latent tuberculosis infection in Canadian plains Aborigines. Am J Respir Crit Care Med 2000; 162:989–993.
100. Steele MA, Burk RF, DesPrez RM. Toxic hepatitis with isoniazid and rifampin: a meta-analysis. Chest 1991;99:465–471.
101. Lacroix C, Tranvouez JL, Phan Hoang T, Duwoos H, Lafont D. Pharmacokinetics of pyrazinamide and its metabolites in patients with hepatic cirrhotic insufficiency. Arzneimittelforschung 1990;40:76–79.
102. Moriwaki Y, Yamamoto T, Nasako Y, Takahashi S, Suda M, Hiroishi K, Hada T, Higashino K. In vitro oxidation of pyrazinamide and allopurinol by rat liver aldehyde oxidase. Biochem Pharmacol 1993; 46:975–981.
103. Yamamoto T, Moriwaki Y, Suda M, Nasako Y, Takahashi S, Hiroishi K, Nakano T, Hada T, Higashino K. Effect of BOF-4272 on the oxidation of allopurinol and pyrazinamide in vivo: is xanthine dehydrogenase or aldehyde oxidase more important in oxidizing both allopurinol and pyrazinamide? Biochem Pharmacol 1993;46:2277–2284.
104. Nasu S, Yamaguchi K, Sakakibara S, Imai H, Ueda I. The effect of pyrazines on the metabolism of tryptophan and nicotinamide adenine dinucleotide in the rat: evidence of the formation of a potent inhibitor of aminocarboxy-muconate-semialdehyde decarboxylase from pyrazinamide. Biochim Biophys Acta 1981;677:109–119.
105. Yamamoto T, Moriwaki Y, Takahashi S, Hada T, Higashino K. Study of the metabolism of pyrazinamide using a high-performance liquid chromatographic analysis of urine samples. Anal Biochem 1987;160: 346–349.
106. American Thoracic Society, Centers for Disease Control and Prevention, Infectious Diseases Society of America. Treatment of tuberculosis. MMWR Morbid Mortal Wkly Rep 2003;52:1–88.
107. Shibata K, Fukuwatari T, Sugimoto E. Effects of dietary pyrazinamide, an antituberculosis agent, on the metabolism of tryptophan to niacin and of tryptophan to serotonin in rats. Biosci Biotechnol Biochem 2001;65:1339–1346.
108. Centers for Disease Control and Prevention, American Thoracic Society. Update: fatal and severe liver injuries associated with rifampin and pyrazinamide for latent tuberculosis infection, and revisions in American Thoracic Society/CDC recommendations: United States, 2001. MMWR Morb Mortal Wkly Rep 2001;50:733–735.
109. Knobel B, Buyanowsky G, Dan M, Zaidel L. Pyrazinamide-induced granulomatous hepatitis. J Clin Gastroenterol 1997;24:264–266.
110. Urban T, Maquarre E, Housset C, Chouaid C, Devin E, Lebeau B. Allopurinol hypersensitivity: a possible cause of hepatitis and mucocutaneous eruptions in a patient undergoing antitubercular treatment. Rev Mal Respir 1995;12:314–316.
111. Lacroix C, Guyonnaud C, Chaou M, Duwoos H, Lafont O. Interaction between allopurinol and pyrazinamide. Eur Respir J 1988;1:807–811.
112. Centers for Disease Control and Prevention, American Thoracic Society. Update: fatal and severe liver injuries associated with rifampin and pyrazinamide treatment for latent tuberculosis infection. MMWR Morb Mortal Wkly Rep 2002;51:998–999.
113. Gordin F, Chaisson RE, Matts JP, Miller C, de Lourdes Garcia M, Hafner R, Valdespino JL, Coberly J, Schechter M, Klukowicz AJ, et al. Rifampin and pyrazinamide vs isoniazid for prevention of tuberculosis in HIV-infected persons: an international randomized trial. JAMA 2000;283:1445–1450.
114. Gordin FM, Cohn DL, Matts JP, Chaisson RE, O'Brien RJ. Hepatotoxicity of rifampin and pyrazinamide in the treatment of latent tuberculosis infection in HIV-infected persons: is it different than in HIV-uninfected persons? Clin Infect Dis 2004;39:561–565.
115. Halsey NA, Coberly J, Desormeaux J, Losikoff P, Atkinson J, Moulton L, Contave M, Johnson M, Davis H, Geiter L, et al. Rifampin and pyrazinamide vs. isoniazid for prevention of tuberculosis in HIV-infected persons: an international randomized trial. Lancet 1998;35I: 786–792.
116. Mwinga A, Hosp M, Godfrey-Faussett P, Quigley M, Mwaba P, Mugala BN, Nyirenda O, Luo N, Pobee J, Elliott AM, et al. Twice weekly tuberculosis preventive therapy in HIV infection in Zambia. AIDS 1998;12:2447–2457.
117. Geiter L, O'Brien R, Kopanoff D. Short-course preventive therapy for tuberculosis [abstract]. Am Rev Respir Dis 1990;141:A437.
118. Geiter L. Results of a randomized, controlled trial to assess the toxicity and patient adherence with two short-course regimens for the prevention of tuberculosis, a two-month regimen of rifampin and pyrazinamide or a four-month regimen of rifampin only, in comparison with a control regimen of six months-isoniazid [thesis]. Baltimore, MD: Johns Hopkins University, School of Hygiene and Public Health; 1997.
119. Grazcyk J, O'Brien R, Bek E, Nimerowsak H, Geiter L. Assessment of rifampin containing regimens for tuberculosis preventive therapy: preliminary results from a pilot study in Poland [abstract]. Am Rev Respir Dis 1991;143:A119.
120. Magdorf K, Arizzi-Ruche A, Geiter L, O'Brien R, Wahn U. Compliance and tolerance of new antituberculotic short term chemoprevention regimes in childhood: a pilot study. Pneumologie 1994;48:761–764.
121. Bock NN, Rogers T, Tapia JR, Herron GD, DeVoe B, Geiter LJ. Acceptability of short-course rifampin and pyrazinamide treatment of latent tuberculosis infection among jail inmates. Chest 2001;119: 833–837.
122. Jasmer RM, Saukkonen JJ, Blumberg HM, Daley CL, Bernardo J, Vittinghoff E, King MD, Kawamura LM, Hopewell PC. Short-course rifampin and pyrazinamide compared with isoniazid for latent tuberculosis infection: a multicenter clinical trial. Ann Intern Med 2002;137: 640–647.
123. Lobato MN, Leary L. Adverse drug effects and treatment outcomes related to treatment for latent tuberculosis infection using rifampin and pyrazinamide. Chest 2005;127:1296–1303.
124. Chaisson RE, Armstrong J, Stafford J, Golub J, Bur S. Safety and tolerability of intermittent rifampin/pyrazinamide for the treatment of latent tuberculosis infection in prisoners [letter]. JAMA 2002;288: 165–166.
125. van Hest R, Baars H, Kik S, van Gerven P, Trompenaars MC, Kalisvaart N, Keizer S, Borgdorff M, Mensen M, Cobelens F. Hepatotoxicity of rifampin-pyrazinamide and isoniazid preventive therapy and tuberculosis treatment. Clin Infect Dis 2004;39:488–496.
126. Stout JE, Engemann JJ, Cheng AC, Fortenberry ER, Hamilton CD. Safety of 2 months of rifampin and pyrazinamide for treatment of latent tuberculosis. Am J Respir Crit Care Med 2003;167:824–827.
127. Perucca E, Grimaldi R, Frigo GM, Sardi A, Monig H, Ohnhaus EE. Comparative effects of rifabutin and rifampicin on hepatic microsomal enzyme activity in normal subjects. Eur J Clin Pharmacol 1988; 34:595–599.
128. Griffith DE, Brown BA, Girard WM, Wallace RJ Jr. Adverse events associated with high-dose rifabutin in macrolide-containing regimens for the treatment of Mycobacterium avium complex lung disease. Clin Infect Dis 1995;21:594–598.
129. Benson CA, Williams PL, Cohn DL, Becker S, Hojczyk P, Nevin T, Korvick JA, Heifets L, Child CC, Lederman MM, et al. Clarithromycin or rifabutin alone or in combination for primary prophylaxis of Mycobacterium avium complex disease in patients with AIDS: a randomized, double-blind, placebo-controlled trial. The AIDS Clinical Trials Group 196/Terry Beirn Community Programs for Clinical Research on AIDS 009 Protocol Team. J Infect Dis 2000;181:1289–1297.
130. Havlir DV, Dube MP, Sattler FR, Forthal DN, Kemper CA, Dunne MW, Parenti DM, Lavelle JP, White AC Jr, Witt MD, et al. Prophylaxis against disseminated Mycobacterium avium complex with weekly azithromycin, daily rifabutin, or both. California Collaborative Treatment Group. N Engl J Med 1996;335:392–398.
131. Gulliford M, Mackay AD, Prowse K. Cholestatic jaundice caused by ethambutol. Br Med J (Clin Res Ed) 1986;292:866.
132. Bertino J Jr, Fish D. The safety profile of the fluoroquinolones. Clin Ther 2000;22:798–817.
133. Wolfson JS, Hooper DC. Overview of fluoroquinolone safety. Am J Med 1991;91:153S–161S.
134. Dombeck M, Duch D, Bennet S, Bell L. Evaluating the implications of long-term safety and efficacy on the use of fluoroquinolones in the treatment of pulmonary tuberculosis. Research Triangle Park, NC: RTI Health Solutions; 2001.
135. Ball P. Long-term use of quinolones and their safety. Rev Infect Dis 1989;11:S1365–S1370.
136. Lazarczyk DA, Goldstein NS, Gordon SC. Trovafloxacin hepatotoxicity. Dig Dis Sci 2001;46:925–926.
137. Labowitz JK, Silverman WB. Cholestatic jaundice induced by ciprofloxacin. Dig Dis Sci 1997;42:192–194.
138. Coleman CI, Spencer JV, Chung JO, Reddy P. Possible gatifloxacin-induced fulminant hepatic failure. Ann Pharmacother 2002;36:1162–1167.
139. Kahn JB. Latest industry information on the safety profile of levofloxacin in the US. Chemotherapy 2001;47:32–37.
140. Ball P, Stahlmann R, Kubin R, Choudhri S, Owens R. Safety profile of oral and intravenous moxifloxacin: cumulative data from clinical trials and postmarketing studies. Clin Ther 2004;26:940–950.
141. Saigal S, Agarwal SR, Nandeesh HP, Sarin SK. Safety of an ofloxacin-based antitubercular regimen for the treatment of tuberculosis in patients with underlying chronic liver disease: a preliminary report. J Gastroenterol Hepatol 2001;16:1028–1032.
142. Ormerod LP, Horsfield N. Frequency and type of reactions to antituberculosis drugs: observations in routine treatment. Tuber Lung Dis 1996;77:37–42.
143. Yee D, Valiquette C, Pelletier M, Parisien I, Rocher I, Menzies D. Incidence of serious side effects from first-line antituberculosis drugs among patients treated for active tuberculosis. Am J Respir Crit Care Med 2003;167:1472–1477.
144. Dossing M, Wilcke JT, Askgaard DS, Nybo B. Liver injury during antituberculosis treatment: an 11-year study. Tuber Lung Dis 1996; 77:335–340.
145. Teleman MD, Chee CB, Earnest A, Wang YT. Hepatotoxicity of tuberculosis chemotherapy under general programme conditions in Singapore. Int J Tuberc Lung Dis 2002;6:699–705.
146. Schaberg T, Rebhan K, Lode H. Risk factors for side-effects of isoniazid, rifampin and pyrazinamide in patients hospitalized for pulmonary tuberculosis. Eur Respir J 1996;9:2026–2030.
147. Hwang SJ, Wu JC, Lee CN, Yen FS, Lu CL, Lin TP, Lee SD. A prospective clinical study of isoniazid-rifampicin-pyrazinamide-induced liver injury in an area endemic for hepatitis B. J Gastroenterol Hepatol 1997;12:87–91.
148. Ohkawa K, Hashiguchi M, Ohno K, Kiuchi C, Takahashi S, Kondo S, Echizen H, Ogata H. Risk factors for antituberculous chemotherapy-induced hepatotoxicity in Japanese pediatric patients. Clin Pharmacol Ther 2002;72:220–226.
149. Tsagaropoulou-Stinga H, Mataki-Emmanouilidou T, Karida-Kavalioti S, Manios S. Hepatotoxic reactions in children with severe tuberculosis treated with isoniazid-rifampin. Pediatr Infect Dis 1985;4:270–273.
150. Parthasarathy R, Sarma GR, Janardhanam B, Ramachandran P, Santha T, Sivasubramanian S, Somasundaram PR, Tripathy SP. Hepatic toxicity in South Indian patients during treatment of tuberculosis with short-course regimens containing isoniazid, rifampicin and pyrazinamide. Tubercle 1986;67:99–108.
151. O'Brien RJ, Long MW, Cross FS, Lyle MA, Snider DE Jr. Hepatotoxicity from isoniazid and rifampin among children treated for tuberculosis. Pediatrics 1983;72:491–499.
152. Algerian Working Group/British Medical Research Council cooperative study. Controlled clinical trial comparing a 6-month and a 12-month regimen in the treatment of pulmonary tuberculosis in the Algerian Sahara. Am Rev Respir Dis 1984;129:921–928.
153. Shakya R, Rao BS, Shrestha B. Incidence of hepatotoxicity due to antitubercular medicines and assessment of risk factors. Ann Pharmacother 2004;38:1074–1079.
154. Cohn DL, Catlin BJ, Peterson KL, Judson FN, Sbarbaro JA. A 62-dose, 6-month therapy for pulmonary and extrapulmonary tuberculosis: a twice-weekly, directly observed, and cost-effective regimen. Ann Intern Med 1990;112:407–415.
155. Singapore Tuberculosis Service/British Medical Research Council. Clinical trial of three 6-month regimens of chemotherapy given intermittently in the continuation phase in the treatment of pulmonary tuberculosis. Am Rev Respir Dis 1985;132:374–378.
156. Neill P, Pringle D, Mhonda M, Kusema T, Nhachi CF. Effects of two pulmonary tuberculosis drug treatments and acetylator status on liver function in a Zimbabwean population. Cent Afr J Med 1990;36:104–107.
157. Hwang SJ, Wu JC, Lee CN, Yen F, Lu C, Lin T, Lee S. A prospective clinical study of isoniazid-rifampicin-pyrazinamide-induced liver injury in an area endemic for hepatitis B. J Gastroenterol Hepatol 1997; 12:87–91.
158. Martinez-Roig A, Cami J, Llorens-Terol J, de la Torre R, Perich F. Acetylation phenotype and hepatotoxicity in the treatment of tuberculosis in children. Pediatrics 1986;77:912–915.
159. Singh J, Garg PK, Tandon RK. Hepatotoxicity due to antituberculosis therapy: clinical profile and reintroduction of therapy. J Clin Gastroenterol 1996;22:211–214.
160. Krishnaswamy K, Prasad CE, Murthy KJ. Hepatic dysfunction in undernourished patients receiving isoniazid and rifampicin. Trop Geogr Med 1991;43:156–160.
161. Sharma SK, Balamurugan A, Saha PK, Pandey RM, Mehra NK. Evaluation of clinical and immunogenetic risk factors for the development of hepatotoxicity during antituberculosis treatment. Am J Respir Crit Care Med 2002;166:916–919.
162. Roy B, Chowdhury A, Kundu S, Santra A, Dey B, Chakraborty M, Majumder PP. Increased risk of antituberculosis drug-induced hepatotoxicity in individuals with glutathione S-transferase M1 ‘null’ mutation. J Gastroenterol Hepatol 2001;16:1033–1037.
163. Meyers BR, Papanicolaou GA, Sheiner P, Emre S, Miller C. Tuberculosis in orthotopic liver transplant patients: increased toxicity of recommended agents; cure of disseminated infection with nonconventional regimens. Transplantation 2000;69:64–69.
164. Howell F, O'Laoide R, Kelly P, Power J, Clancy L. Short course chemotherapy for pulmonary tuberculosis: a randomised controlled trial of a six month versus a nine month oral regimen. Ir Med J 1989;82:11–13.
165. Zierski M, Bek E. Side-effects of drug regimens used in short-course chemotherapy for pulmonary tuberculosis: a controlled clinical study. Tubercle 1980;61:41–49.
166. Combs DL, O'Brien RJ, Geiter LJ. USPHS Tuberculosis Short-Course Chemotherapy Trial 21: effectiveness, toxicity and acceptability: report of the final results. Ann Intern Med 1990;112:397–406.
167. Cohen CD, Sayed AR, Kirsch RE. Hepatic complications of antituberculosis therapy revisited. S Afr Med J 1983;63:960–963.
168. Small PM, Schecter GF, Goodman PC, Sande MA, Chaisson RE, Hopewell PC. Treatment of tuberculosis in patients with advanced human immunodeficiency virus infection. N Engl J Med 1991;324:289–294.
169. European Tuberculosis Study Group. Tuberculosis in HIV-infected patients: a multicentric randomized comparative study of a three- versus a four-drug regimen [abstract PoB3077]. Presented at the Eighth International Conference on AIDS/III STD World Congress; 1992; Amsterdam, Netherlands.
170. El-Sadr WM, Perlman DC, Matts JP, Nelson E, Cohn D, Salomon N, Olibrice M, Medard F, Chirgwin K, Mildvan D, et al. Evaluation of an intensive intermittent-induction regimen and duration of short-course treatment for human immunodeficiency virus-related pulmonary tuberculosis. Clin Infect Dis 1998;26:1148–1158.
171. Dworkin MS, Adams MR, Cohn DL, Davidson A, Buskin S, Horwitch C, Morse A, Sackoff J, Thompson M, Wotring L, et al. Factors that complicate the treatment of tuberculosis in HIV-infected patients. J Acquir Immune Defic Syndr 2005;39:464–470.
172. Chaisson RE, Clermont HC, Holt EA, Cantave M, Johnson M, Atkinson J, Davis H, Boulos R, Quinn T, Halsey N. Six-month supervised intermittent tuberculosis therapy in Haitian patients with and without HIV infection. Am J Respir Crit Care Med 1996;154:1034–1038.
173. Ungo JR, Jones D, Ashkin D, Hollender E, Bernstein D, Albanese A, Pitchenik A. Antituberculosis drug-induced hepatotoxicity: the role of hepatitis C virus and the human immunodeficiency virus. Am J Respir Crit Care Med 1998;157:1871–1876.
174. Wu JC, Lee SD, Yeh PF, Chan C, Wang Y, Huang Y, Tsai Y, Lee P, Ting L, Lo K. Isoniazid-rifampin-induced hepatitis in hepatitis B carriers. Gastroenterology 1990;98:502–504.
175. Wong WM, Wu PC, Yuen MF, Cheng C, Yew W, Wong P, Tam C, Leung C, Lai C. Antituberculosis drug-related liver dysfunction in chronic hepatitis B infection. Hepatology 2000;31:201–206.
176. Lee BH, Koh WJ, Choi MS, Suh GY, Chung MP, Kim H, Kwon OJ. Inactive hepatitis B surface antigen carrier state and hepatotoxicity during antituberculosis chemotherapy. Chest 2005;127:1304–1311.
177. Pernod J. Hepatic tolerance of ethionamide. Am Rev Respir Dis 1965; 92:39–42.
178. Phillips S, Tashman H. Ethionamide jaundice. Am Rev Respir Dis 1963; 87:896–898.
179. British Tuberculosis Association. A comparison of the toxicity of prothionamide and ethionamide: a report from the research committee of the British Tuberculosis Association. Tubercle 1968;49:125–135.
180. Somner AR, Brace AA. Changes in serum transaminase due to prothionamide. Tubercle 1967;48:137–143.
181. Rossouw JE, Saunders SJ. Hepatic complications of antituberculous therapy. Q J Med 1975;XLIV:1–16.
182. Lok AS, McMahon BJ; Practice Guidelines Committee, American Association for the Study of Liver Diseases. Chronic hepatitis B: update of recommendations. Hepatology 2004;39:857–861.
183. World Health Organization. Treatment of tuberculosis: guidelines for national programmes, 2nd ed. Geneva, Switzerland: World Health Organization; 1997. Publication No. WHO/TB/97.220.
184. Enarson D, Rieder H, Arnadottir T, Trébucq A. Management of tuberculosis: a guide for low income countries, 5th ed. Paris: International Union Against Tuberculosis and Lung Disease; 2000. Available from: http://www.iuatld.org/pdf/en/guides_publications/management_of_tb.pdf

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