Orexin antagonists, also known as orexin receptor antagonists or dual orexin receptor antagonists (DORAs), are a class of drugs that inhibit the action of orexin neuropeptides.
Orexin (hypocretin) , is a neurotransmitter that regulates wakefulness, arousal, and appetite.
By blocking the action of orexin, these antagonists promote sleep and are typically used in the treatment of insomnia.
Survorexant (Belsomra) works by blocking the orexin 1 and orexin 2 receptors, thereby suppressing the wake-promoting effects of orexin and helping individuals fall and stay asleep.
Orexin containing neurons in the lateral hypothalamus stimulate wake promoting nuclei in the brain stem and hypothalamus, and inhibited sleep promoting nuclei in the ventral lateral and median preoptic areas:inhibiting or anergic neurotransmission, inhibits, wakefulness and promote sleep.
Three dual orexin receptor antagonists, survorexant, lemborexant and daridorexant are approved for insomnia.
These medications usually offer a different mechanism of action compared to traditional sleep aids, such as benzodiazepines or non-benzodiazepine hypnotics (like zolpidem), which generally work by enhancing the action of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter.