Ciprostene is a synthetic, chemically stable analog of prostacyclin (PGI2). In animal models, administration of ciprostene resulted in dose-dependent hypotension, tachycardia, and inhibition of ex vivo ADP-induced platelet aggregation. Ciprostene was evaluated in clinical trials in patients with peripheral vascular disease. It was found to reduce restenosis in patients with coronary artery disease undergoing therapeutic percutaneous transluminal coronary angioplasty.

Cilobamine is a drug which acts as a norepinephrine-dopamine reuptake inhibitor (NDRI) and has stimulant and antidepressant effects.

Ciclazindol is an indole derivative and monoamine uptake inhibitor patented by pharmaceutical company John Wyeth and Brother Ltd. as an antidepressant. Besides that, Ciclazindol is effective anorectic agent, inducing weight loss in rats and man. Ciclazindol was shown to inhibit ATP-sensitive K+ (K(ATP)) channel currents and stimulate insulin secretion from CRI-G1 insulin-secreting cells. The inhibition of KATP channel currents by ciclazindol is unaffected by the removal of intracellular Mg2+ ions and after trypsinization of the cytoplasmic surface of excised patches, treatments known to abolish sulphonylurea sensitivity.

Clomoxir (POCA, B 807-27) is a potent inhibitor of mitochondrial fatty acid oxidation at the stage of carnitine palmitoyltransferase I (CPT-I). It acts by the tight binding of POCA-CoA to this enzyme. The compound demonstrated hypoketonaemic and hypoglycaemic activities in fasted normal and diabetic rats.

Cloxestradiol is a chlorinated derivative of estradiol, invented by Danish company Leo Pharma AS in 1963. The compound is claimed to have estrogenic activity, as was demonstrated by the extended duration of oestrus caused by the injection of cloxestradiol to castrated female rats.

Ciprefadol is an opioid analgesic drug. It binds with a high affinity to mu (Ki 4.2 nM) and kappa (Ki 2.5 nM) opioid receptors. In vivo, ciprefadol displays mixed antagonist/agonist activity in the mouse writhing and the rat tail heat tests: in low doses, the compound inhibits the analgesic effect of morphine, while at higher doses it displays analgesic effect. Chronic administration of ciprefadol to rhesus monkeys produced a marked physical dependence more severe than that of morphine, and its effect was consistent with what would be expected of a potent, long-lasting morphine-like agonist.

Clocanfamide is a gastric secretory inhibitor, known in Italy under tradename Clamiren.

Somantadine, an adamantane derivative, is an antiviral agent. Somantadine was synthesized by Pennwalt and has been undergoing tests for the treatment of herpes virus for nearly five years.

Cimicoxib is a selective cyclooxygenase 2 inhibitor used in veterinary medicine to treat dogs for pain and inflammation associated with osteoarthritis and for the management of pain and inflammation associated with surgery. Limited data are available on cimicoxib, with one study documenting non-inferiority compared to carprofen in managing postoperative pain for dogs undergoing either orthopedic or soft tissue surgery. There are some data available as part of cimicoxib’s approval process in Europe to support its use for chronic pain.

Ritobegron (KUC 7483) is a selective β3-adrenoceptor agonist that was developed for oral treatment of overactive bladder. It is the prodrug of the active compound KUC-7322. Phase I studies have investigated the pharmacodynamic and pharmacokinetic effects of ritobegron in healthy individuals and patients with spinal cord injury. Ritobegron exhibits a high selectivity for the bladder versus other organs, and decreased intravesical pressure with minimal effects on the cardiovascular system in rats. When administered in combination with organic anion transporter (OAT) inhibitors such as probenecid (primarily used in treating gout and hyperuricemia), the plasma concentration of the active compound KUC-7322 may increase.