Description: Indiplon (NBI-34060; CL-285,489) is a nonbenzodiazepine class of hypnotic sedative which works by enhancing the action of the inhibitory neurotransmitter GABA, like most other nonbenzodiazepine sedatives. It primarily binds to the α1 subunits of the GABAA receptors in the brain. Indiplon was approved for the treatment of insomnia. Like other non-benzodiazepine hypnotics, its mechanism of action is to modulate subunits, especially the alpha-1 subunit, of the GABA receptor complex in order to induce sedation. Indiplon was developed in two different formulations to address two different types of indiplon-IR (immediate release) was designed for sleep onset difficulties, while indiplon-MR (modified release) was developed for sleep maintenance insomnia. While there are currently few peer reviewed articles about indiplon clinical trial results, the early information that is available seems to indicate that both formulations have been well tolerated and have proven effective at improving both patient reported and objectively measured sleep parameters in both adult and elderly insomnia patients. In May 2006, the FDA indicated that indiplon-IR was approvable and plans are to resubmit the application in 2007. Indiplon-MR was unapprovable and may require further evaluation.