Mirtazapine, sold under the brand name Remeron among others, is an atypical tetracyclic antidepressant, and as such is used primarily to treat depression. Its effects may take up to four weeks but can also manifest as early as one to two weeks. It is often used in cases of depression complicated by anxiety or insomnia. The effectiveness of mirtazapine is comparable to other commonly prescribed antidepressants. It is taken by mouth.
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).
Rimonabant (also known as SR141716; trade names Acomplia, Zimulti) is an anorectic antiobesity drug approved in Europe in 2006 but was withdrawn worldwide in 2008 due to serious psychiatric side effects; it was never approved in the United States. Rimonabant is an inverse agonist for the cannabinoid receptor CB1 and was first-in-class for clinical development.
Eszopiclone, sold under the brand name Lunesta among others, is a medication used in the treatment of insomnia. Evidence supports slight to moderate benefit up to six months. It is taken by mouth.
Doxylamine is an antihistamine medication used to treat insomnia and allergies, and—in combination with pyridoxine (vitamin B6)—to treat morning sickness in pregnant women. It is available over-the-counter and is typically sold under such brand names as Equate or Unisom, among others; and it is used in nighttime cold medicines (e.g., NyQuil) and pain medications containing acetaminophen and/or codeine to help with sleep. The medication is delivered chemically by the salt doxylamine succinate and is taken by mouth. Doxylamine and other first-generation antihistamines are the most widely used sleep medications in the world. Typical side effects of doxylamine (at recommended doses) include dizziness, drowsiness, grogginess, and dry mouth, among others.
Trazodone, sold under many brand names, is an antidepressant medication, used to treat major depressive disorder, anxiety disorders, and insomnia. It is a phenylpiperazine compound of the serotonin antagonist and reuptake inhibitor (SARI) class. The medication is taken orally.
Ritanserin, also known by its developmental code name R-55667, is a serotonin antagonist medication described as an anxiolytic, antidepressant, antiparkinsonian agent, and antihypertensive agent. It was chiefly investigated as a drug to treat insomnia, especially to enhance sleep quality by significantly increasing slow wave sleep by virtue of potent and concomitant 5HT2a and 5HT2c antagonism
Ramelteon, sold under the brand name Rozerem among others, is a melatonin agonist medication which is used in the treatment of insomnia. It is indicated specifically for the treatment of insomnia characterized by difficulties with sleep onset. It reduces the time taken to fall asleep, but the degree of clinical benefit is small. The medication is approved for long-term use. Ramelteon is taken by mouth.
The 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor (GPCR). The 5-HT2A receptor is a cell surface receptor, but has several intracellular locations.
Dianicline (SSR-591,813) is a drug developed by Sanofi-Aventis which acts as a partial agonist at neural nicotinic acetylcholine receptors. It is subtype-selective, binding primarily to the α4β2 subtype. It is being developed as a medication for the treatment of nicotine dependence to assist in smoking cessation. Dianicline is very similar to the already marketed drug varenicline and it is unclear what advantages it will have over the older drug, although it may have an improved side effect profile. It has been through human trials up to Phase II, although results have not yet been reported. Drug development has been discontinued after reporting of unfavourable results during Phase III trials.
Osanetant (developmental code name SR-142,801) is a neurokinin 3 receptor antagonist which was developed by Sanofi-Synthélabo and was being researched for the treatment of schizophrenia but was discontinued. It was the first non-peptide NK3 antagonist developed in the mid-1990s.
Pimavanserin, sold under the brand name Nuplazid, is an atypical antipsychotic which is approved for the treatment of Parkinson's disease psychosis. Unlike other antipsychotics, pimavanserin is not a dopamine receptor antagonist, but rather is a selective inverse agonist of the serotonin 5-HT2A receptor.
Volinanserin (INN) is a highly selective 5-HT2A receptor antagonist that is frequently used in scientific research to investigate the function of the 5-HT2A receptor. It was also tested in clinical trials as a potential antipsychotic, antidepressant, and treatment for insomnia but was never marketed.
Esmirtazapine (ORG-50,081) is a tetracyclic antidepressant drug that was under development by Organon for the treatment of insomnia and vasomotor symptoms (e.g., hot flashes) associated with menopause. Esmirtazapine is the (S)-(+)-enantiomer of mirtazapine and possesses similar overall pharmacology, including inverse agonist actions at H1 and 5-HT2 receptors and antagonist actions at α2-adrenergic receptors.
Pruvanserin is a selective 5-HT2A receptor antagonist which was under development by Eli Lilly and Company for the treatment of insomnia. It was in phase II clinical trials in 2008 but appears to have been discontinued as it is no longer in the company's development pipeline. In addition to its sleep-improving properties, pruvanserin has also been shown to have antidepressant, anxiolytic, and working memory-enhancing effects in animal studies.
Cariprazine, sold under the brand name Vraylar among others, is an atypical antipsychotic developed by Gedeon Richter, which is used in the treatment of schizophrenia, bipolar mania, bipolar depression, and major depressive disorder. It acts primarily as a D3 and D2 receptor partial agonist, with a preference for the D3 receptor. Cariprazine is also a partial agonist at the serotonin 5-HT1A receptor and acts as an antagonist at 5-HT2B and 5-HT2A receptors, with high selectivity for the D3 receptor. It is taken by mouth.
Nelotanserin is a drug developed by Arena Pharmaceuticals which acts as an inverse agonist on the serotonin receptor subtype 5-HT2A and was under development for the treatment of insomnia. It was shown to be effective and well tolerated in clinical trials, but development was halted in December 2008 because the substance did not meet the trial's effectiveness endpoints. Research continues on newer analogues which may potentially be more successful.
Brexpiprazole, sold under the brand name Rexulti among others, is an atypical antipsychotic medication used for the treatment of major depressive disorder, schizophrenia, and agitation associated with dementia due to Alzheimer's disease.
Drinabant (INN; AVE-1625) is a drug that acts as a selective CB1 receptor antagonist, which was under investigation varyingly by Sanofi-Aventis as a treatment for obesity, schizophrenia, Alzheimer's disease, Parkinson's disease, and nicotine dependence. Though initially studied as a potential treatment for a variety of different medical conditions, Sanofi-Aventis eventually narrowed down the therapeutic indications of the compound to just appetite suppression. Drinabant reached phase IIb clinical trials for this purpose in the treatment of obesity but was shortly thereafter discontinued, likely due to the observation of severe psychiatric side effects including anxiety, depression, and thoughts of suicide in patients treated with the now-withdrawn rimonabant, another CB1 antagonist that was also under development by Sanofi-Aventis.
TIK-301 (LY-156735) is an agonist for the melatonin receptors MT1 and MT2 that is under development for the treatment of insomnia and other sleep disorders. Its agonist action on MT1 and MT2 receptors in the suprachiasmatic nucleus in the brain enables its action as a chronobiotic. It is in the same class of melatonin receptor agonists as ramelteon and tasimelteon.
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