feeding. [ 83 ] Diazepam undergoes oxidative metabolism by CYP2C19 in the liver as part of the cytochrome P450 enzyme system. It has a biphasic half-life of 1–2 and 2–5 days, and has several pharmacologically active metabolites. The main active metabolite of diazepam is desmethyldiazepam (also known as nordazepam or nordiazepam