Effect of physiological characteristics, smoking, and alcohol use on isoniazid hair drug levels among pulmonary TB patients: a cross-sectional study at one month of intensive TB treatment.

Background: Tuberculosis(TB) is still among the leading causes of death from a single infectious pathogen worldwide. TB treatment is long, requires multiple drug combinations, and therefore adherence monitoring. TB hair drug levels have been suggested as a technique of treatment adherence monitoring; however, the drug levels might be affected by physiological factors, alcohol use, and cigarette smoking. This can affect the pharmacokinetics and pharmacodynamics of TB drugs.

Objective: To assess the effect of physiological factors, smoking, and alcohol on isoniazid hair drug levels during TB treatment.

Methods: Patients were assessed for diabetes Mellitus, smoking, alcohol consumption, age, weight, and gender. Hair drug levels were measured by Liquid Chromatography Mass Spectrometry(LC-MS).

Results: We screened a total of 102 TB patients and enrolled 56 participants out of which 50 completed the study. We excluded 15 participants who were not sampled exactly at 1-month appointment dates and of the remaining 35; the mean hair drug level was 0.0706ng/mg, 95% CI: 0.0303-0.1109. Tests of interaction across the different subgroups yielded no statistically significant interaction coefficients(IC) except for age and gender (IC=-0.36.95%, CI: -0.55-0.17, P=0.001).

Conclusion: Physiological factors, alcohol, and smoking do not affect isoniazid hair drug levels.