Levalmodipine (S-amlodipine) is an active enantiomer of amlodipine, a calcium antagonist that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Experimental data suggest that S-amlodipine binds to both dihydropyridine and nondihydropyridine binding sites. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. S-Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Enantiomerically pure S-amlodipine is marketed in some countries worldwide, while racemate, containing active S-enantiomer an inactive R-enantiomer is marketed in the USA and indicated for the treatment of hypertension and coronary artery disease.

Halofantrine is a blood schizonticidal antimalarial agent with no apparent action on the sporozoite, gametocyte or hepatic stages of the infection. It is used only to treat but not to prevent malaria. Has been marketed by GlaxoSmithKline as HALFAN (halofantrine hydrochloride) in 250 mg tablets indicated for the treatment of adults who can tolerate oral medication and who have mild to moderate malaria (equal to or less than 100,000 parasites/mm3) caused by Plasmodium falciparum or Plasmodium vivax. Among side effects is cardiac arrhythmia. It belongs to the phenanthrene class of compounds that includes quinine and lumefantrine. It was reported that halofantrine binds to hematin in vitro (crystal structure of the complex) and to to plasmpesin, a haemoglobin degrading enzyme unique to the malarial parasites.

Bepridil is a calcium channel blocker that has well characterized anti-anginal properties and known but poorly characterized type 1 anti-arrhythmic and anti-hypertensive properties. It has inhibitory effects on both the slow calcium and fast sodium inward currents in myocardial and vascular smooth muscle, interferes with calcium binding to calmodulin, and blocks both voltage and receptor operated calcium channels. It is used to treat hypertension (high blood pressure), angina (chest pain), sustained atrial fibrillation and tachyarrhythmia. The most common side effects were upper gastrointestinal complaints (nausea, dyspepsia or GI distress), diarrhea, dizziness, asthenia and nervousness. Certain drugs could increase the likelihood of potentially serious adverse effects with bepridil hydrochloride. In general, these are drugs that have one or more pharmacologic activities similar to bepridil hydrochloride, including anti-arrhythmic agents such as quinidine and procainamide, cardiac glycosides and tricyclic anti-depressants. Anti-arrhythmics and tricyclic anti-depressants could exaggerate the prolongation of the QT interval observed with bepridil hydrochloride. Cardiac glycosides could exaggerate the depression of AV nodal conduction observed with bepridil hydrochloride.

Pinacidil is a clinically effective vasodilator used for the treatment of hypertension.

Astemizole is antihistamine drug, discovered by Janssen Pharmaceutical and used to prevent sneezing, runny nose, itching and watering of the eyes, and other allergic symptoms. The drug was withdrawn from U.S. market in 1999 due to the potential to cause arrhythmias at high doses.

Guanabenz, an antihypertensive agent for oral administration-, is an aminoguanidine derivative, 2,'6-dichlorobenzylideneamina-guanidine acetate. It is white to an almost white powder having not more than a slight odor. Sparingly soluble in water and in 0.1 N hydrochloric acid; soluble in alcohol and in propylene glycol. Guanabenz is an orally active central alpha-2 adrenergic agonist. Its antihypertensive action appears to be mediated via stimulation of central alpha-adrenergic receptors, resulting in a decrease of sympathetic outflow from the brain at the bulbar level to the peripheral circulatory system. In clinical trials, guanabenz acetate, given orally to hypertensive patients, effectively controlled blood pressure without any significant effect on glomerular filtration rate, renal blood flow, body fluid volume or body weight. The Myelin Repair Foundation and the National Institutes of Health (National Institute of Neurological Disorders and Stroke) are developing guanabenz for the treatment of multiple sclerosis. Unlike the currently available treatment for multiple sclerosis that suppresses the immune system, guanabenz, an FDA approved the drug for the treatment of high blood pressure, has a potential to reduce the loss of myelin by protecting and repairing myelin-producing cells in the brain from damage. Phase I development is underway in the US.

Niclosamide is an antihelminth used against tapeworm infections. It may act by the uncoupling of the electron transport chain to ATP synthase. The disturbance of this crucial metabolic pathway prevents creation of adenosine tri-phosphate (ATP), an essential molecule that supplies energy for metabolism. Niclosamide works by killing tapeworms on contact. Adult worms (but not ova) are rapidly killed, presumably due to uncoupling of oxidative phosphorylation or stimulation of ATPase activity. The killed worms are then passed in the stool or sometimes destroyed in the intestine. Niclosamide may work as a molluscicide by binding to and damaging DNA. Niclosamide is used for the treatment of tapeworm and intestinal fluke infections: Taenia saginata (Beef Tapeworm), Taenia solium (Pork Tapeworm), Diphyllobothrium latum (Fish Tapeworm), Fasciolopsis buski (large intestinal fluke). Niclosamide is also used as a molluscicide in the control of schistosomiasis. Niclosamide was marketed under the trade name Niclocide, now discontinued.

Zomepirac Sodium (Zomax) is a pyrrole-acetic acid structurally related to tolmetin sodium. Zomepirac is a prostaglandin synthetase inhibitor and is not an opioid, an opioid antagonist, or a salicylate. Zomepirac was approved by the Food and Drug Administration for marketing in the United States as an analgesic. It was indicated for all forms of mild to moderately severe pain, and was being promoted as a "comprehensive, non-addicting analgesic." Later Zomepirac was found to be associated with fatal and near-fatal anaphylactoid reactions. The manufacturer voluntarily removed Zomax tablets from the Canadian, US, and UK markets in March 1983.

Maprotiline is a tetracyclic antidepressant with similar pharmacological properties to tricyclic antidepressants (TCAs). Similar to TCAs, maprotiline inhibits neuronal norepinephrine reuptake, possesses some anticholinergic activity, and does not affect monoamine oxidase activity. It differs from TCAs in that it does not appear to block serotonin reuptake. Maprotiline may be used to treat depressive affective disorders, including dysthymic disorder (depressive neurosis) and major depressive disorder. Maprotiline is effective at reducing symptoms of anxiety associated with depression. The mechanism of action of maprotiline is not precisely known. It does not act primarily by stimulation of the central nervous system and is not a monoamine oxidase inhibitor. The postulated mechanism of maprotiline is that it acts primarily by potentiation of central adrenergic synapses by blocking reuptake of norepinephrine at nerve endings. This pharmacologic action is thought to be responsible for the drug’s antidepressant and anxiolytic effects. The mean time to peak is 12 hours. The half-life of elimination averages 51 hours.

Quinestrol is a synthetic estrogen that is effective in hormone replacement therapy. It is a 3-cyclopentyl ether of ethynyl estradiol. After gastrointestinal absorption, it is stored in adipose tissue, where it is slowly released and metabolized in the liver to its active form, ethinyl estradiol. Quinestrol has found limited use in suppressing lactation in postpartum women and, in combination with synthetic progestogens, as contraceptive therapy, although additional studies are needed for both applications. Estrogens diffuse into their target cells and interact with a protein receptor (the estrogen receptor). Estrogen interacts with a target cell receptor. When the estrogen receptor has bound its ligand it can enter the nucleus of the target cell, and regulate gene transcription which leads to formation of messenger RNA. The mRNA interacts with ribosomes to produce specific proteins that express the effect of estradiol upon the target cell. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. The combination of an estrogen with a progestin suppresses the hypothalamic-pituitary system, decreasing the secretion of gonadotropin-releasing hormone (GnRH).