Suvorexant, sold under the trade name Belsomra, is a medication for the treatment of insomnia. It is effective for insomnia, at least for four weeks and as compared to a placebo.
Suvorexant is a selective, dual orexin receptor antagonist made by Merck & Co. It was approved for sale by the U.S. Food and Drug Administration (FDA) on August 13, 2014. The U.S. Drug Enforcement Administration (DEA) has placed it on the list of schedule IV controlled substances, as it may lead to limited physical dependence or psychological dependence relative to the drugs or other substances in schedule III. The potential for psychological dependence is similar to that of zolpidem. The drug became available in Japan in November 2014 and in the United States in February 2015.
Suvorexant is used for the treatment of insomnia, characterized by difficulties with sleep onset and/or sleep maintenance.
It is unclear how the medications compare to others used for insomnia as no comparisons have been done. It is also unclear if this medication is safe among people with a history of addiction, as they were excluded from the clinical trials of suvorexant.
The most common complaint about the drug is from users who report that it did not help them to sleep. Some people reported that the drug caused a sleep disturbance such as a nightmare, sleep terror, or abnormal dream. Others reported that the drug caused them to be more awake.
Issues include sleepiness the next day and issues with driving. Other concerns include thoughts of suicide.
There have been reports of people performing complex tasks (such as cooking and eating, making phone calls, driving, having sex) with little recollection of the events with the use of hypnotics such as suvorexant.
This drug is not recommended in people with liver impairment. Suvorexant pregnancy category is currently classified as Category C. Based on animal testing, this medication may cause fetal harm during pregnancy and should only be given in pregnancy if the potential benefit justifies the potential harm to the fetus. Evidence is inconclusive about whether using this medication while breastfeeding puts the infant at risk of harm.
Suvorexant is contraindicated in people diagnosed with narcolepsy.
Suvorexant is not recommended if people are also taking medications that strongly inhibit the liver enzyme CYP3A like itraconazole, lopinavir/ritonavir, clarithromycin, ritonavir, ketoconazole, indinavir/ritonavir, or conivaptan. If suvorexant is used with a medication that moderately inhibits the liver enzyme CYP3A, like verapamil, erythromycin, diltiazem, or dronedarone, it is recommended that the dose of suvorexant be adjusted.
Suvorexant exerts its therapeutic effect in insomnia through antagonism of orexin receptors. The orexin neuropeptide signaling system is a central promoter of wakefulness. Blocking the binding of wake-promoting neuropeptides orexin A and orexin B to receptors orexin receptor type 1 (OX1) and orexin receptor type 2 (OX2) is thought to suppress wake drive. Animal studies report the binding affinities for OX1 (0.55 nM) and OX2 (0.35 nM).
The bioavailability of suvorexant is at 82%. It is highly protein-bound. Food delays the time to max concentration. The primary route of elimination is through the feces, with approximately 66% of radiolabeled dose recovered in the feces compared to 23% in the urine.The elimination half-life is reported to be 12 hours.
According to the U.S. Drug Enforcement Administration (DEA), suvorexant produces similar reinforcing effects to those of zolpidem in humans and thus may have a similar abuse liability. As such, suvorexant has been designated a schedule IV controlled substance in the U.S. under the Controlled Substances Act.