Biochemical and pharmacological properties of oxazepam.

Oxazepam is the final metabolic product in vitro and in vivo of a large number of pharmacologically active benzodiazepines. Oxazepam shows antimetrazol activity varying in intensity and duration according to the animal species considered. This difference is in part related to different "sensitivity" and in part due to different disposition of oxazepam. Particularly relevant is the difference in biliary excretion by various animal species. Oxazepam is currently available as a racemate but two optical isomers can be separated as succinate half esters. The (+) form appears to be more active than the (-) form, probably because more oxazepam is released from the (+) than the (-) isomer in vivo. In vitro studies confirm that the liver hydrolyzes the (+) oxazepam succinate half ester more than the (-) form. Other work has aimed at analyzing the effects of oxazepam on brain chemical mediators, with particular reference to the cholinergic system. Finally it is shown that oxazepam, similarly to other benzodiazepines, increased aggressiveness in male mice during chronic treatment.