Sulamserod is a methanesulfonamide derivative patented by British multinational pharmaceutical company GlaxoSmithKline as 5-HT4 receptor antagonist, with antiarrhythmic activities for the treatment of the certain cardiovascular condition. 5-HT4 receptor blockade could have antiarrhythmic effects by decreasing intracellular Ca2+ concentration and delayed rectifier potassium current and prolonging atrial refractory period. In preclinical models, Sulamserod prolongs mean atrial effective refractory period and wavelength, reduces the dispersion of effective refractory period, and minimally slows conduction velocity in pigs.

Xinomiline is an antihypertensive agent that gas never been marketed. Information about the current use of this agent is not available.

Felipyrine is a 1-aryl-2-pyrrolidinone derivative exerting anti-inflammatory activity.

Sonedenoson (MRE0094) is a topical adenosine A2A-receptor agonist which was under clinical development for the treatment of for diabetic foot ulcer. The compound was originally developed by New York University, and licensed to Medco Research (King Pharmaceuticals). King Pharmaceuticals was acquired by Pfizer in 2010. Sonedenoson has been in phase II clinical trials for the treatment of chronic diabetic neuropathic foot ulcers. However, this research has been discontinued.

Phencarbamide is an anti-spasmodic and anticholinergic drug used during parturition. It has a specific antispasmodic action on the smooth muscle, both directly like papaverine and through the autonomic nervous system (atropine effect). It has also an analgesic effect of its own. Side-effects generally associated with the atropine group of drugs.

Zaltidine (CP-57,361) is a guanidinothiazolylimidazole compound which is a highly specific H2-receptor antagonist. It potently inhibits gastric acid secretion. Zaltidine appears to be an effective treatment of duodenal ulcer in human studies. However, the incidence of hepatic damage (8%) seems higher than with commonly used H2-receptor antagonists.

Telcagepant (MK-0974) is a calcitonin gene-related peptide receptor antagonist. Merck & Co was developing telcagepant for the treatment of pain. Telcagepant is an extremely potent CGRP antagonist with a Ki = 0.77 (0.07 nM). Telcagepant showed efficacy against acute migraines; however, different patient populations may show more beneficial effects with telcagepant versus triptans. In the acute treatment of migraine, Telcagepant was found to have equal potency to rizatriptan and zolmitriptan in two Phase III clinical trials. Merck & Co has now terminated development of the drug.

Serlopitant, Originally developed by Merck, is a once-daily oral NK1 receptor antagonist being developed for the treatment of pruritus, or itch, associated with various conditions such as prurigo nodularis, psoriasis and chronic pruritus of unknown origin. It is highly selective for the human NK1 receptor and in both animal and human testing it has been well tolerated. In 2012, Merck licensed serlopitant to Menlo to develop it in indications other than nausea and vomiting. Development of serlopitant for the treatment of overactive bladder, alcohol dependence and pruritus was discontinued at phase II, by Merck & Co. and Japan. Menlo has completed three positive Phase 2 clinical trials with serlopitant showing a statistically significant reduction in pruritus compared to placebo. Serlopitant has been evaluated in over 1,600 patients and has been shown to be well-tolerated, including in patients who have received treatment for up to one year. Serlopitant is an investigational drug that is not currently approved for use in any indication in any country.

Revizinone (R-80122) is a selective phosphodiesterase (PDE) III inhibitor, developed for use in treatment of heart failure and ischaemic heart disorders. Revizinone showed positive inotropic and possibly moderate vasodilating properties in dogs, and it was concluded that revizinone has a clinically favorable cardiovascular profile for acute applications in heart failure. In patients with impaired left ventricular function, revizinone was also found to be a potent positive inotropic agent. The drug was safe, its use not associated with marked vasodilation, and no positive chronotropic effects were reported.