Assessment of age-related isoniazid hepatotoxicity during treatment of latent tuberculosis infection

ABSTRACT

Background: Since the introduction of new recommendations for the treatment of latent tuberculosis infection (LTB1) disregarding age as a limitation, increasing numbers of older individuals are expected to undergo treatment with isoniazid for the prevention of tuberculosis, raising the potential for an increase in isoniazid hepatotoxicity.

Objective: To compare the frequency of hepatotoxicity requiring withdrawal of isoniazid therapy for LTB1 in patients under and over 35 years of age, managed according to current practice guidelines.

Design: A retrospective analysis of 300 patients who underwent isoniazid therapy for LTB1 according to a protocol based on the current practice guidelines.

Setting: Public health clinic of Passaic County, NJ.

Main outcome measures: The frequency of symptomatic isoniazid hepatitis in various age groups.

Results: Of 165 patients < 35 years of age, 3(2%) patients developed hepatitis (AST > 3 times the upper limit of normal). Of 135 patients ≥ 35 years of age, 4(3%) patients developed hepatitis. Statistical comparison between the two groups failed to show a significant difference ( p = 0.705).

Conclusions: No difference was detected in the frequency of isoniazid hepatotoxicity between patients < 35 and ≥ 35 years of age. Clinically monitored isoniazid therapy of LTB1 patients ≥ 35 years of age may not predispose subjects to an increased risk of hepatotoxicity. Limitations of this work include the small sample size and the retrospective nature of the study.

Key words: :

• Hepatotoxicity
• Isoniazid
• Liver function
• Tuberculosis infection

Notes

* Presented, in part, at the Annual meeting of the American College of Chest Physicians, Seattle Washington, Oct 23–28, 2004