异烟肼吸收后,大部分在肝内经N-乙酰基转移酶的催化进行乙酰化,代谢为无活性的乙酰异烟肼和异烟酸,并与少量原形物最终经肾排出。异烟肼在体内乙酰化的速度个体差异甚大,因此,把机体分为快代谢型和慢代谢型。快代谢型肾脏分泌的尿液中原形药物的量仅及慢代谢型的1/5～1/2,而尿中乙 After isoniazid uptake, most are acetylated in the liver by N-acetyltransferase catalysis, metabolized to inactive acetyl isoniazid and isonicotinic acid, and eventually excreted with small amounts of the final form via the kidneys. Isoniazid in vivo acetylation rate of individual differences are very large, therefore, the body is divided into fast metabolism and slow metabolism. Quick metabolism of urine secreted by the urine of prototype drugs and slow metabolism only 1/5 ~ 1/2, while urine B