Indiplon

Indiplon is an investigational hypnotic that has been evaluated in efficacy and safety studies as a possible treatment for insomnia. It is a positive allosteric modulator of GABA responses at the GABA_A receptor complex and has selectivity for receptors containing the α1 subunit subtype. The compound's short elimination half-life has allowed the development of immediate-release and modified-release formulations. Clinical trials have been conducted with populations of adult and elderly insomnia subjects. Safety assessments suggest that indiplon is well-tolerated in both groups. The immediate-release capsule has been shown to be beneficial for sleep onset at bedtime or during middle-of-the-night awakenings, while the modified-release formulation has positive efficacy for sleep onset and sleep maintenance. At present, neither formulation has been approved by the US Food and Drug Administration or regulatory organizations in other countries.