Azapirones are a class of drugs used as anxiolytics, antidepressants, and antipsychotics. They are commonly used as add-ons to other antidepressants, such as selective serotonin reuptake inhibitors (SSRIs).
Etoperidone, associated with several brand names, is an atypical antidepressant which was developed in the 1970s and either is no longer marketed or was never marketed. It is a phenylpiperazine related to trazodone and nefazodone in chemical structure and is a serotonin antagonist and reuptake inhibitor (SARI) similarly to them.
The orexin receptor (also referred to as the hypocretin receptor) is a G-protein-coupled receptor that binds the neuropeptide orexin. There are two variants, OX1 and OX2, each encoded by a different gene (HCRTR1, HCRTR2).
Nalfurafine is an antipruritic that is marketed in Japan for the treatment of uremic pruritus in individuals with chronic kidney disease undergoing hemodialysis. It activates the κ-opioid receptor (KOR) and is potent, selective, and centrally active. It was the first selective KOR agonist approved for clinical use. It has also been dubiously referred to as the "first non-narcotic opioid drug" in history.
Orexin receptor type 2 (Ox2R or OX2), also known as hypocretin receptor type 2 (HcrtR2), is a protein that in humans is encoded by the HCRTR2 gene. It should not be confused for the protein CD200R1 which shares the alias OX2R but is a distinct, unrelated gene located on the human chromosome 3.
Vedaclidine (INN, codenamed LY-297,802, NNC 11-1053) is an experimental analgesic drug which acts as a mixed agonist–antagonist at muscarinic acetylcholine receptors, being a potent and selective agonist for the M1 and M4 subtypes, yet an antagonist at the M2, M3 and M5 subtypes. It is orally active and an effective analgesic over 3× the potency of morphine, with side effects such as salivation and tremor only occurring at many times the effective analgesic dose. Human trials showed little potential for development of dependence or abuse, and research is continuing into possible clinical application in the treatment of neuropathic pain and cancer pain relief.
Capeserod (INN; development code SL65.0155) is a selective 5-HT4 receptor partial agonist with Ki = 0.6 nM and IA = 40–50% (relative to serotonin). It potently enhances cognition, learning, and memory, and also possesses antidepressant effects. Capeserod was in phase II clinical trials around 2004–2006 for the treatment of memory deficits and dementia but no new information has surfaced since and it appears to have been abandoned.
Cenicriviroc is an experimental drug candidate for the treatment of HIV infection and in combination with Tropifexor for non-alcoholic steatohepatitis. It is being developed by Takeda and Tobira Therapeutics.
Brigatinib, sold under the brand name Alunbrig among others, is a small-molecule targeted cancer therapy being developed by Ariad Pharmaceuticals, Inc. Brigatinib acts as both an anaplastic lymphoma kinase (ALK) and epidermal growth factor receptor (EGFR) inhibitor.
Velusetrag (INN, USAN; previously known as TD-5108) is an experimental drug candidate for the treatment of gastric neuromuscular disorders including gastroparesis, and lower gastrointestinal motility disorders including chronic idiopathic constipation and irritable bowel syndrome. It is a potent, selective, high efficacy 5-HT4 receptor serotonin agonist being developed by Theravance Biopharma and Alfa Wassermann. Velusetrag demonstrates less selectivity for other serotonin receptors, such as 5-HT2 and 5-HT3, to earlier generation 5-HT agonists like cisapride and tegaserod.
Abediterol is a once-daily experimental drug candidate for the treatment of asthma and chronic obstructive pulmonary disease (COPD), but it has never been marketed.
Lemborexant, sold under the brand name Dayvigo, is an orexin antagonist medication which is used in the treatment of insomnia. It is indicated specifically for the treatment of insomnia characterized by difficulties with sleep onset and/or maintenance in adults. The medication is taken by mouth.
Sufugolix (INNTooltip International Nonproprietary Name, BANTooltip British Approved Name) (developmental code name TAK-013) is a non-peptide, orally-active, selective antagonist of the gonadotropin-releasing hormone receptor (GnRHR) (IC50Tooltip Half-maximal inhibitory concentration = 0.1 and 0.06 nM for affinity and in vitro inhibition, respectively). It was under development by Takeda for the treatment of endometriosis and uterine leiomyoma and reached phase II clinical trials for both of these indications, but was subsequently discontinued. It seems to have been supplanted by relugolix (TAK-385), which is also under development by Takeda for the treatment of these conditions and has a more favorable drug profile (including reduced cytochrome P450 inhibition and improved in vivo GnRHR antagonistic activity) in comparison.
Carmoterol is a non-catechol experimental ultra-long-acting β adrenoreceptor agonist (ultra-LABA) that was in clinical trials before 2010 when it has been withdrawn from further development based on evidence that the compound does not possess a competitive profile.
Ulotaront is an investigational antipsychotic that is undergoing clinical trials for the treatment of schizophrenia and Parkinson's disease psychosis. The medication was discovered in collaboration between PsychoGenics Inc. and Sunovion Pharmaceuticals using PsychoGenics' behavior and AI-based phenotypic drug discovery platform, SmartCube. Ulotaront is in Phase III of clinical development.
Vibegron, sold under the brand name Gemtesa, is a medication for the treatment of overactive bladder. Vibegron is a selective beta-3 adrenergic receptor agonist.
Danavorexton is a selective orexin 2 receptor agonist. It is a small-molecule compound and is administered intravenously. The compound was found to dose-dependently produce wakefulness to a similar degree as modafinil in a phase 1 clinical trial. As of March 2021, danavorexton is under development for the treatment of narcolepsy, idiopathic hypersomnia, and sleep apnea. It is related to another orexin receptor agonist, firazorexton (TAK-994), the development of which was discontinued for safety reasons in October 2021.
Firazorexton (INNTooltip International Nonproprietary Name; development code TAK-994) is an experimental orexin 2 (OX2) receptor agonist first described in a 2019 patent filed by Takeda Pharmaceutical Company.
