New pharmacological strategies for the management of insomnia : Suvorexant, one receptor antagonists orexin

The pharmacological management strategies for insomnia have focused on two types of drugs: those that increase the inhibition of GABA-A system, such as barbiturates, benzodiazepines and even alcohol, and those promoting signal interruption of histaminergic neurons of the posterior hypothalamus, that are tonic wakefulness related. In the late twentieth century a system of neuropeptides orexin or hypocretin, that corresponding to a pair of proteins whose neurons are located predominantly in the lateral hypothalamus was discovered. Two years later, it was reported that in a natural model of narcolepsy Doberman dog with an autosomal dominate pattern, that there is a mutation of OREX-2 receptor. Narcolepsy is characterized by sleep attacks of short duration, sudden muscle weakness linked to emotional aspects (cataplexy), hypnagogic and hypnopompic hallucinations and paralysis sleep. A series of antagonists of orexin receptors has been tested as hypnotics. Antagonists that bind to one of the two orexin receptors are called SORAs (single orexin receptor antagonist), while there are some that acting on the two receptor subtypes, DORAs (dual orexin receptor antagonist). Until today there have been four DORAs: suvorexant, filorexant, SB-649.898 and almorexant. In the present review the potential benefits and risks of this type of suvorexant, which was recently approved as a hypnotic exposed in the United States and Japan.