Ubrogepant, a small molecule drug, is being developed by Merck & Co for the treatment of migraine. The calcitonin gene-related peptide receptor (CGRP) antagonist is administered orally as a film coated tablet. Ubrogepant is a competitive antagonist with high affinity, potency, and selectivity for the human CGRP receptor. In the four clinical studies (ACHIEVE I, ACHIEVE II, UBR-MD-04 and 3110-105-002) ubrogepant demonstrated efficacy, safety and tolerability in the acute treatment of migraine among a broad patient population, including those who had an insufficient response to a triptan or those patients in whom triptans were contraindicated, as well as in patients who had moderate to severe CV risk profile.

Lofexidine is newly FDA approved in the United States under the brand name LUCEMYRA for the treatment of opioid withdrawal symptoms in adults. Lofexidine acts as an agonist to α2 adrenergic receptors. These receptors inhibit adenylyl cyclase activity, leading to the inhibition of the second messenger, cyclic adenosine monophosphate (cAMP). The inhibition of cAMP leads to potassium efflux through calcium-activated channels, blocking calcium ions from entering the nerve terminal, resulting in suppression of neural firing, inhibition of norepinephrine release. Lofexidine replaces the opioid-driven inhibition of cAMP production and moderating the symptoms of opioid withdrawal.

Revefenacin (trade name Yupelri is a long-acting muscarinic antagonist developed by Mylan Ireland ltd for the treatment of chronic obstructive pulmonary disease (COPD). It has similar affinity to the subtypes of muscarinic receptors M1 to M5. In the airways, it exhibits pharmacological effects through inhibition of M3 receptor at the smooth muscle leading to bronchodilation. The competitive and reversible nature of antagonism was shown with human and animal origin receptors and isolated organ preparations. In preclinical in vitro as well as in vivo models, prevention of methacholine- and acetylcholine-induced bronchoconstrictive effects was dose-dependent and lasted longer than 24 hours.

Stiripentol is an anticonvulsant drug used in the treatment of epilepsy. It recently proved to increase the GABAergic transmission in vitro in an experimental model of immature rat. Clinical studies were based on the fact that STP also acts as an inhibitor of CYP3A4, CYP1A2, and CYP2C19 in vivo in epileptic patients. Side effects are largely due to the increase in plasma concentrations of other anticonvulsants and can be reduced by lowering the dose of those drugs. Nausea and vomiting are particularly noted when used in combination with sodium valproate. It appears to increase the potency of phenobarbital, primidone, phenytoin, carbamazepine, clobazam and diazepam.

Prucalopride is a novel enterokinetic compound and is the first representative of the benzofuran class. Prucalopride is a potent, selective and specific serotonin 5-HT4 receptor (5-HT4-R) agonist. Prucalopride (Resolor®), a highly selective serotonin 5-HT4 receptor agonist, is indicated in the European Economic Area for the treatment of adults with chronic idiopathic constipation (CIC) in whom laxatives have failed to provide adequate relief.

Elagolix (ABT-620) is an oral gonadotropin-releasing hormone antagonist being studied for the treatment of endometriosis and uterine fibroids. The U.S. Food and Drug Administration (FDA) approved AbbVie's elagolix under the brand name Orilissa as the first and only oral gonadotropin-releasing hormone (GnRH) antagonist specifically developed for women with moderate to severe endometriosis pain.

Pimavanserin, marketed under the trade name Nuplazid, a non-dopaminergic atypical antipsychotic developed by Acadia Pharmaceuticals is the first and only medication approved by the U.S. Food and Drug Administration (FDA) for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. The mechanism of action of pimavanserin in the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis is unknown. However, the effect of pimavanserin could be mediated through a combination of inverse agonist and antagonist activity at serotonin 5-HT2A receptors and to a lesser extent at serotonin 5-HT2C receptors. In vitro, pimavanserin acts as an inverse agonist and antagonist at serotonin 5-HT2A receptors with high binding affinity (Ki value 0.087 nM) and at serotonin 5-HT2C receptors with lower binding affinity (Ki value 0.44 nM). Pimavanserin shows low binding to sigma 1 receptors (Ki value 120 nM) and has no appreciable affinity (Ki value >300 nM), to serotonin 5-HT2B, dopaminergic (including D2), muscarinic, histaminergic, or adrenergic receptors, or to calcium channels. Pimavanserin was approved by the FDA to treat hallucinations and delusions associated with psychosis experienced by some people with Parkinson's disease on April 29, 2016.

Flibanserin is the first drug to be approved for hypoactive sexual desire disorder (HSDD) in premenopausal women by the FDA in August 2015. It was originally developed as an antidepressant medication by Boehringer Ingelheim, but showed lack of efficacy in trials and was further developed as a hypoactive sexual disorder drug by Sprout Pharmaceuticals. Flibanserin's mechanism of action is attributed to its high affinity for 5-HTA1 and 5-HTA2 receptors, displaying agonist activity on 5-HTA1 and antagonist on 5-HTA2, resulting in lowering of serotonin in the brain as well as an effect on increasing norepinephrine and dopamine neurotransmitters. Flibansetrin has high affinity for serotonin receptors in the brain: it acts as an agonist on 5-HT1A and an antagonist on 5-HT2A. In vivo, flibanserin binds equally to 5-HT1A and 5-HT2A receptors. However, under higher levels of brain 5-HT (i.e., under stress), flibanserin may occupy 5-HT2A receptors in higher proportion than 5-HT(1A) receptors. It may also moderately antagonize D4 (dopamine) receptors and 5-HT2B and 5-HTB2C. Its action on neurotransmitter receptors may contribute to reduction in serotonin levels and increase in dopamine and norepinephrine levels, all of which may play part in reward processing. Flibanserin is sold under the trade name Addyi and indicated for the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD) as characterized by low sexual desire that causes marked distress or interpersonal difficulty.

Rolapitant (VARUBI) is neurokinin 1 (NK1) receptor antagonist. Rolapitant does not have significant affinity for the NK2 or NK3 receptors. Drug is indicated in combination with other antiemetic agents in adults for the prevention of delayed nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including, but not limited to, highly emetogenic chemotherapy. Most common adverse reactions are: neutropenia and hiccups at Cisplatin Based Highly Emetogenic Chemotherapy; decreased appetite, neutropenia and dizziness at Moderately Emetogenic Chemotherapy and Combinations of Anthracycline and Cyclophosphamide. Inhibition of BCRP and P-gp by rolapitant can increase plasma concentrations of the concomitant drug and potential for adverse reactions. Strong CYP3A4 Inducers (e.g., rifampin) can significantly reduce plasma concentrations of rolapitant and decrease the efficacy of VARUBI.

Fosnetupitant is a prodrug form of netupitant. Netupitant is a selective antagonist of human substance P/neurokinin 1 (NK-1) receptors. Upon intravenous administration, fosnetupitant is converted by phosphatases to its active form. It competitively binds to and blocks the activity of NK-1 receptors in the central nervous system, by inhibiting binding of substance P (SP) to NK-1 receptors. This prevents delayed emesis, which is associated with SP secretion. AKYNZEO® is a combination of palonosetron, a serotonin-3 receptor antagonist, and netupitant (capsules for oral use) or fosnetupitant (injections for intravenous use). AKYNZEO® for injection is indicated in combination with dexamethasone in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy.