Flunitrazepam - Pharmacokinetics

Pharmacokinetics

While 80% of flunitrazepam that is taken orally is absorbed, bioavailability in suppository form is closer to 50%.

Flunitrazepam has a long half-life of 18–26 hours and an active metabolite that has a half-life of 36–200 hours, which means that flunitrazepam's effects after nighttime administration persist throughout the next day. Residual "hangover" effects after nighttime administration of flunitrazepam, such as sleepiness and impaired psychomotor and cognitive functions, may persist into the next day. This may impair the ability of users to drive safely, and increase risks of falls and hip fractures.

Flunitrazepam is lipophilic and is metabolised hepatically via oxidative pathways. The enzyme CYP3A4 is the main enzyme in its phase 1 metabolism in human liver microsomes.