The type of isoniazid acetylation in tuberculosis patients treated at National Tuberculosis and Lung Diseases Research Institute.

The research has dealt with types of acetylation in 237 TB patients treated by standard course of chemotherapy with a 300 mg dose of INH at the National Tuberculosis and Lung Diseases Research Institute in Warsaw (NTLDRI). Blood samples were taken before (time 0) and 1, 3, 6 and 24 h after drug administration. Plasma concentrations of isoniazid were determined with biological methods. Two indicators of acetylation rate--I3 and C6 have been used to determine the acetylation type. Majority of the treated patients (68.8%) have shown fast type of INH acetylation. After similar dose of isoniazid different profile of absorption and excretion of the drug and significant differences (p < 0.01) in INH concentrations, acetylation rate and bioavailability between 163 fast and 74 slow acetylators have been observed. In plasma of 38.6% fast acetylators drug concentration 3h after ingestion of the dose did not achieve the concentration of 1 mcg/ml. In plasma of 29.7% slow acetylators, concentrations of INH 6h after ingestion were higher than 2 mcg/ml.