CYP2E1 genotype and isoniazid-induced hepatotoxicity in patients treated for latent tuberculosis

Eur J Clin Pharmacol. 2006 Jun;62(6):423-9. doi: 10.1007/s00228-006-0111-5. Epub 2006 Apr 27.


Objective: To determine whether pharmacogenetic tests such as N-acetyltransferase 2 (NAT2) and cytochrome P450 2E1 (CYP2E1) genotyping are useful in identifying patients prone to antituberculosis drug-induced hepatotoxicity in a cosmopolite population.

Methods: In a prospective study we genotyped 89 patients treated with isoniazid (INH) for latent tuberculosis. INH-induced hepatitis (INH-H) or elevated liver enzymes including hepatitis (INH-ELE) was diagnosed based on the clinical diagnostic scale (CDS) designed for routine clinical practice. NAT2 genotypes were assessed by fluorescence resonance energy transfer probe after PCR analysis, and CYP2E1 genotypes were determined by PCR with restriction fragment length polymorphism analysis.

Results: Twenty-six patients (29%) had INH-ELE, while eight (9%) presented with INH-H leading to INH treatment interruption. We report no significant influence of NAT2 polymorphism, but we did find a significant association between the CYP2E1 *1A/*1A genotype and INH-ELE (OR: 3.4; 95% CI:1.1-12; p = 0.02) and a non significant trend for INH-H (OR: 5.9; 95% CI: 0.69-270; p = 0.13) compared with other CYP2E1 genotypes. This test for predicting INH-ELE had a positive predictive value (PPV) of 39% (95% CI: 26-54%) and a negative predictive value (NPV) of 84% (95% CI: 69-94%).

Conclusion: The genotyping of CYP2E1 polymorphisms may be a useful predictive tool in the common setting of a highly heterogeneous population for predicting isoniazid-induced hepatic toxicity. Larger prospective randomized trials are needed to confirm these results.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antitubercular Agents / adverse effects*
  • Antitubercular Agents / metabolism
  • Arylamine N-Acetyltransferase / genetics
  • Base Sequence
  • Chemical and Drug Induced Liver Injury / enzymology
  • Chemical and Drug Induced Liver Injury / etiology
  • Chemical and Drug Induced Liver Injury / genetics
  • Cytochrome P-450 CYP2E1 / genetics*
  • DNA Primers / genetics
  • Female
  • Gene Frequency
  • Genotype
  • Humans
  • Isoniazid / adverse effects*
  • Isoniazid / metabolism
  • Liver / drug effects*
  • Male
  • Middle Aged
  • Pharmacogenetics
  • Polymorphism, Restriction Fragment Length
  • Prospective Studies
  • Tuberculosis, Pulmonary / drug therapy


  • Antitubercular Agents
  • DNA Primers
  • Cytochrome P-450 CYP2E1
  • Arylamine N-Acetyltransferase
  • NAT2 protein, human
  • Isoniazid