n. a benzodiazepine used for the management of anxiety disorders and the short-term treatment of insomnia. As with most of the long-acting benzodiazepines, halazepam is metabolized to the active intermediate compound desmethyldiazepam (nordiazepam), which has a very long half-life (and therefore duration of action). This allows halazepam to be taken only once a day but also is associated with its accumulation in older adults and other people with reduced ability to metabolize the long-acting benzodiazepines. U.S. trade name: Paxipam.