Absorption: Well absorbed (90%) from the GI tract; absorption is slower with extended-release tablets.

Distribution: Widely distributed, crosses blood-brain barrier. Probably crosses the placenta and enters breast milk. Accumulation is minimal.

Metabolism and Excretion: Metabolized by the liver (CYP3A4 enzyme system) to an active compound that is subsequently rapidly metabolized.

Half-life: 12–15 hr.

TIME/ACTION PROFILE (sedation)