Vietnam ranks 13th among the 23 countries that must deal with 80% of global deaths from tuberculosis (1). The National Tuberculosis Control Program of Vietnam implemented the WHO DOTS (directly observed therapy, short course) strategy in 1989. The standard treatment regimen for previously untreated patients consists of 2 months of streptomycin, isoniazid (INH), rifampin, and pyrazinamide, followed by 6 months of INH and ethambutol (the 2SHRZ/6HE regimen). INH, a central component of this chemotherapy, is extensively metabolized by the polymorphic N -acetyltransferase 2 (NAT2) enzyme. N -acetyltransferase 2 (arylamine N -acetyltransferase) ( NAT2 ) gene polymorphisms are associated with individual phenotypes generally classified as INH rapid (homozygous or heterozygous) and slow acetylators. Among the described NAT2 alleles, NAT2*5 , * 6 , * 7 , 12 *, * 14 , * 17 , and * 19 have been associated with the slow acetylator phenotype, and NAT2*4 and * 13 are associated with fast acetylation. Under treatment with standard dosages, patients who are slow metabolizers …