Indiplon: the development of a novel therapy for the treatment of sleep onset and sleep maintenance insomnia

Indiplon is a novel non-benzodiazepine sedative-hypnotic that modulates the GABAA receptor complex. It appears to be more selective for the alpha1-receptor subunit, associated with sedation, than other hypnotics. Two different formulations of indiplon have been developed: an immediate release (IR) version targeting sleep onset insomnia and a modified release (MR) version addressing sleep maintenance insomnia. Early results from clinical trials indicate that both formulations are well tolerated and effective at improving both objective and subjective measures of sleep. As of May 2006 indiplon-IR has been provisionally approved for use in the US market and discussions are continuing with the FDA regarding the MR formulation.