Domperidone is a peripherally selective D2 receptor antagonist. It acts as an antiemetic and a prokinetic agent through its effects on the chemoreceptor trigger zone and motor function of the stomach and small intestine. Domperidone was not approved in USA due to risks of cardiac arrhythmias, cardiac arrest, and sudden death, but is available in other countries. However, FDA allows access to Domperidone through an expanded access investigational new drug application (IND) to patients with gastroesophageal reflux disease with upper GI symptoms, gastroparesis, and chronic constipation. As an “off-label” use, domperidone is prescribed to breastfeeding women to enhance their milk production.

An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. Papaverine is a vasodilating agent. Papaverine is used for the treating certain conditions that are accompanied by smooth muscle spasms (eg, blood vessel, urinary, gallbladder, or intestinal spasm). Papaverine is a nonxanthine phosphodiesterase inhibitor for the relief of cerebral and peripheral ischemia associated with arterial spasm and myocardial ischemia complicated by arrhythmias. The main actions of Papaverine are exerted on cardiac and smooth muscle. Like qathidine, Papaverine acts directly on the heart muscle to depress conduction and prolong the refractory period. Papaverine relaxes various smooth muscles. This relaxation may be prominent if spasm exists. The muscle cell is not paralyzed by Papaverine and still responds to drugs and other stimuli causing contraction. The antispasmodic effect is a direct one, and unrelated to muscle innervation. Papaverine is practically devoid of effects on the central nervous system. Papaverine relaxes the smooth musculature of the larger blood vessels, especially coronary, systemic peripheral, and pulmonary arteries. Papaverine is a potent, specific inhibitor of PDE10A. Papaverine for treatment of erectile dysfunction (ED) is excluded from coverage.

Alprenolol is a beta adrenoreceptor blocking agent and 5HT1A antagonist, developed by AstraZeneca and now available as generic drug. It is used for treatment of hypertension, angina pectoris due to coronary atherosclerosis and acute myocardial infarction.

Fenclozic acid emerged in the late 1960s as a promising carboxylic acid non-steroidal anti-inflammatory drug candidate that demonstrated potent anti-inflammatory, anti-pyretic and analgesic properties. Whole body autoradiography showed fenclozic acid distribution into all tissues except the brain, with radioactivity still detectable in blood, kidney and liver at 72 h post-dose. Fenclozic acid was compared with aspirin in a double-blind, crossover trial in patients with rheumatoid arthritis. It was concluded that fenclozic acid afforded symptomatic relief and was comparable to aspirin. Unfortunately, hepatotoxicity was observed in subsequent trials and the drug was withdrawn from the clinic.

Sertindole (brand names: "Serdolect" and "Serlect") is an antipsychotic medication. Sertindole was developed by the Danish pharmaceutical company Lundbeck and marketed under license by Abbott Labs. Like other atypical antipsychotics, it has activity at dopamine and serotonin receptors in the brain. It is used in the treatment of schizophrenia. Sertindole is not approved for use in the United States and was discontinued in Australia in January 2014. In Europe, sertindole was approved and marketed in 19 countries from 1996, but its marketing authorization was suspended by the European Medicines Agency in 1998 and the drug was withdrawn from the market. In 2002, based on new data, the EMA's CHMP suggested that Sertindole could be reintroduced for restricted use in clinical trials, with strong safeguards including extensive contraindications and warnings for patients at risk of cardiac dysrhythmias, a recommended reduction in maximum dose from 24 mg to 20 mg in all but exceptional cases, and extensive ECG monitoring requirement before and during treatment.

Xamoterol (ICI 118,587) is a partial agonist of beta1-adrenoceptors. Xamoterol acts on the cardiac beta 1-adrenergic receptor, modifies the response of the heart to variations in sympathetic activity. At rest, it produces modest improvements in cardiac contractility, relaxation, and filling without increase in myocardial oxygen demand. The improvements are maintained during exercise although the attendant tachycardia is attenuated. The beneficial effects of xamoterol on both systolic and diastolic function suggested that it would be effective in patients with mild-to-moderate heart failure, and this was demonstrated in small placebo-controlled studies where effort tolerance and symptoms were improved. Xamoterol produced improvements in exercise capacity, clinical signs, symptoms and quality of life with a low incidence of adverse experiences. Xamoterol is effective as monotherapy in heart failure.

Melperone is an antipsychotic drug which is used in Europe for the treatment of sleep disorders, agitation and confusion states. The exact mechanism of melperone action is unknown.

Benzbromarone (INN) is a uricosuric agent and non-competitive inhibitor of xanthine oxidase used in the treatment of gout, especially when the first line treatment, allopurinol, fails or produces intolerable adverse effects. It is structurally related to the antiarrhythmic amiodarone. Benzbromarone was introduced in the 1970s and was viewed as having few associated serious adverse reactions. It was registered in about 20 countries throughout Asia, South America and Europe. In 2003, the drug was withdrawn by Sanofi-Synthélabo, after reports of serious hepatotoxicity, although it is still marketed in several countries by other drug companies. The withdrawal has greatly limited its availability around the world and increased difficulty in accessing it in other countries where it has never been available. Standard dosages of benzbromarone (100 mg/day) tend to produce greater hypouricaemic effects than standard doses of allopourinol (300 mg/day) or probenecid (1000 mg/day). Adverse effects associated with benzbromarone are relatively infrequent but potentially severe. Four cases of benzbromarone-induced hepatotoxicity were identified from primary literature, and eleven cases have been reported by Sanofi-Synthélabo but details are not available in the public domain. Only one of the four publicly published cases demonstrated a clear relationship between the drug and liver injury as demonstrated by rechallenge. The other three cases lacked incontrovertible evidence to support a diagnosis of benzbromarone-induced hepatotoxicity. If all the reported cases are assumed to be due to benzbromarone, the estimated risk of hepatotoxicity in Europe was approximately 1 in 17 000 patients but may be higher in Japan. Benzbromarone is a very potent inhibitor of CYP2C9. The mechanism of benzbromarone hepatotoxicity is believed to be due to its hepatic metabolism by CYP2C9 and possible effects of the parent compound or its metabolites on mitochondrial function. Benzbromarone is a benzofuran and shares structural similarities with benzarone and amiodarone, all three of which affect mitochondrial function.

Ebastine is an antihistamine which blocks H1-receptors through its carboxylic acid metabolite. Ebastine is indicated for the treatment of allergic rhinitis and chronic idiopathic urticaria.

Silymarin, a plant-derived flavonoid from the plant Silybum marianum, is considered the most potential drug to treat almost all kind of liver diseases, particularly alcoholic liver disease, acute and chronic viral hepatitis and toxins-mediated liver dysfunctions. The main component of the silymarin complex is silybin, synonymous with silibinin, sometimes incorrectly called silybinin, which is a mixture of two diastereomers A and B in approximately 1:1 proportion. The drug possess hepatoprotective and antioxidant activity. The hepatoprotective effect is due to stimulation of synthesis of structural and functional proteins and phospholipids, as well as acceleration of the regeneration of hepatocytes. Antioxidant effect is determined by interaction of bioflavones with free radicals in the liver and its detoxication. In such manner the process of peroxidation of the lipids is interrupted and further liver destruction is prevented. Side effect is a mild laxative effect has occasionally been observed.