Incidence of isoniazid acetylation phenotypes in North Indians

Isoniazid acetylation phenotypes were determined in 110 cases (55 of pulmonary tuberculosis and 55 of nontubercular chest diseases) by sulphadimidine acetylation test (Bratton and Marshall method). Cases with more than 65% of acetylated sulphadimidine in urine at 6th h were classified as fast acetylators, those with less than 50% as slow acetylators and others with values between 50-65% as intermediate acetylators. There were 39.09% fast, 46.36% intermediate and 14.55% slow acetylators. Possible factors for difference in results from other Indian studies have been discussed. Sulphadimidine acetylation showed no variation due to presence of disease, age, sex, religion, place of origin, height, weight and smoking habits. However, 79% of those who took alcohol regularly turned out to be fast acetylators.