title: Hepatotoxicity of pyrazinamide: cohort and case-control analyses.
abstract: BACKGROUND
  Relatively little is known about the hepatotoxicity of pyrazinamide.
  
  
  OBJECTIVE
  We compared continuation-phase regimens incorporating pyrazinamide, isoniazid, and/or rifampin with those containing isoniazid and rifampin to evaluate the hepatotoxicity of pyrazinamide.
  
  
  METHODS
  Cohort and nested case-control analyses were conducted on a cohort of 3,007 patients with active tuberculosis (TB) managed at government chest clinics under a TB control program with treatment started from January 1 through June 30, 2001. Cases included all patients with probable hepatotoxicity from 12 or more weeks after starting treatment. Hepatotoxicity was considered probable when serum alanine transaminase exceeded three times the upper limit of normal. Each case was matched by sex and age with three control subjects selected randomly from the rest of the cohort. Treatment regimens of cases within 4 weeks preceding hepatotoxicity were compared with those of matched control subjects in comparable periods relative to the date of commencing treatment.
  
  
  RESULTS
  Hepatotoxicity occurred in 150 (5.0%) patients at any time including 48 (1.6%) cases. From 12 or more weeks after starting treatment, the estimated risk of hepatotoxicity was 2.6% for regimens incorporating pyrazinamide, isoniazid, and/or rifampin, and 0.8% for standard regimens containing isoniazid and rifampin. Multivariable conditional logistic analysis showed a significant association between hepatotoxicity and, respectively, hepatitis B, previous hepatotoxicity, and treatment regimens. The adjusted odds ratio (95% confidence interval) of hepatotoxicity for regimens incorporating pyrazinamide, isoniazid, and/or rifampin relative to standard regimens was 2.8 (1.4-5.9).
  
  
  CONCLUSIONS
  Adding pyrazinamide to isoniazid and rifampin increases the risk of hepatotoxicity appreciably.
authors.affiliation: Tuberculosis and Chest Service, Centre for Health Protection, Department of Health, Hong Kong, China. kc_chang@dh.gov.hk
authors.forename: Kwok C
authors.initials: KC
authors.lastname: Chang
authors.forename: Chi C
authors.initials: CC
authors.lastname: Leung
authors.forename: Wing W
authors.initials: WW
authors.lastname: Yew
authors.forename: Tat Y
authors.initials: TY
authors.lastname: Lau
authors.forename: Cheuk M
authors.initials: CM
authors.lastname: Tam
mesh_terms: D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007538:Isoniazid / Q000008:administration & dosage / Q000009:adverse effects; D016015:Logistic Models; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D015999:Multivariate Analysis; D011718:Pyrazinamide / Q000008:administration & dosage / Q000009:adverse effects*; D012293:Rifampin / Q000008:administration & dosage / Q000009:adverse effects; D014376:Tuberculosis / Q000188:drug therapy*
chemical_list: D000995:Antitubercular Agents; D011718:Pyrazinamide; D007538:Isoniazid; D012293:Rifampin