Ondansetron (ZOFRAN®) is a selective 5-HT3 receptor antagonist. It is effective in the treatment of nausea and vomiting caused by radiotherapy, anesthesia, surgery or cytotoxic chemotherapy drugs, including cisplatin, and has reported anxiolytic and neuroleptic properties. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. It is not certain whether ondansetron's antiemetic action is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. The released serotonin may stimulate the vagal afferents through the 5-HT3 receptors and initiate the vomiting reflex.

Felodipine is a long-acting 1,4-dihydropyridine calcium channel blocker (CCB)b. It acts primarily on vascular smooth muscle cells by stabilizing voltage-gated L-type calcium channels in their inactive conformation. By inhibiting the influx of calcium in smooth muscle cells, felodipine prevents calcium-dependent myocyte contraction and vasoconstriction. Felodipine is the most potent CCB in use and is unique in that it exhibits fluorescent activity. In addition to binding to L-type calcium channels, felodipine binds to a number of calcium-binding proteins, exhibits competitive antagonism of the mineralcorticoid receptor, inhibits the activity of calmodulin-dependent cyclic nucleotide phosphodiesterase, and blocks calcium influx through voltage-gated T-type calcium channels. Felodipine is used to treat mild to moderate essential hypertension.

Azithromycin is one of the world's best-selling antibiotics, used to treat or prevent certain bacterial infections: Acute bacterial exacerbations of chronic bronchitis in adults; acute bacterial sinusitis in adults; uncomplicated skin and skin structure infections in adults; urethritis and cervicitis in adults; genital ulcer disease in men; acute otitis media in pediatric patients; community-acquired pneumonia in adults and pediatric patients; pharyngitis/tonsillitis in adults and pediatric patients. Azithromycin should not be used in patients with pneumonia who are judged inappropriate for oral therapy because of moderate to severe illness or risk factors. A team of researchers at the Croatian pharmaceutical company Pliva, discovered azithromycin in 1980. It was patented in 1981. In 1986, Pliva and Pfizer signed a licensing agreement, which gave Pfizer exclusive rights for the sale of azithromycin in Western Europe and the United States. Pliva put its azithromycin on the market in Central and Eastern Europe under the brand name of Sumamed in 1988. Pfizer launched azithromycin under Pliva's license in other markets under the brand name Zithromax in 1991. Azithromycin is a semi-synthetic macrolide antibiotic of the azalide class. Like other macrolide antibiotics, azithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit of the bacterial 70S ribosome. Binding inhibits peptidyl transferase activity and interferes with amino acid translocation during the process of translation. Its effects may be bacteriostatic or bactericidal depending of the organism and the drug concentration. Its long half-life, which enables once daily dosing and shorter administration durations, is a property distinct from other macrolides.

Propafenone (brand name Rythmol SR or Rytmonorm) is a class 1C anti-arrhythmic medication, which treats illnesses associated with rapid heartbeats such as atrial and ventricular arrhythmias. The electrophysiological effect of propafenone manifests itself in a reduction of upstroke velocity (Phase 0) of the monophasic action potential. In Purkinje fibers, and to a lesser extent myocardial fibers, propafenone reduces the fast inward current carried by sodium ions, which is responsible for the drugs antiarrhythmic actions. Diastolic excitability threshold is increased and effective refractory period prolonged. Propafenone reduces spontaneous automaticity and depresses triggered activity. At very high concentrations in vitro, propafenone can inhibit the slow inward current carried by calcium but this calcium antagonist effect probably does not contribute to antiarrhythmic efficacy. Propafenone is metabolized primarily in the liver. Because of its short half-life, it requires dosing two or three times daily to maintain steady blood levels. The long-term safety of propafenone is unknown. Because it is structurally similar to another anti-arrhythmic medicine, flecainide, similar cautions should be exercised in its use. Flecainide and propafenone, like other antiarrhythmic drugs, have been shown to increase the occurrence of arrhythmias (5.3% for propafenone, Teva physician prescribing information), primarily in patients with underlying heart disease. However, their use in structurally normal hearts is considered safe.

Clozapine was discovered in 1958 by an anesthetist and now it is used for the treatment of schizophrenia. Although the exact mechanism of its action is unknown, the effect of clozapine on schizophrenia is associated with inhibition of dopamine D2 and serotonin 2A receptors.

ALBENZA (albendazole) is an orally administered anthelmintic drug. Chemically, it is methyl 5¬ (propylthio)-2-benzimidazolecarbamate, is indicated to treatment of parenchymal neurocysticercosis due to active lesions caused by larval forms of the pork tapeworm, Taenia solium. In addition, treatment of cystic hydatid disease of the liver, lung, and peritoneum, caused by the larval form of the dog tapeworm, Echinococcus granulosus. Albendazole binds to the colchicine-sensitive site of β-tubulin inhibiting their polymerization into microtubules. The decrease in microtubules in the intestinal cells of the parasites decreases their absorptive function, especially the uptake of glucose by the adult and larval forms of the parasites, and depletes glycogen storage. Insufficient glucose results in insufficient energy for the production of adenosine trisphosphate (ATP) and the parasite eventually dies. Albendazole developed in 1975. It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. The incidence of side effects reported in the published literature is very low, with only gastrointestinal side effects occurring with an overall frequency of just >1% . Albendazole's unique broad-spectrum activity is exemplified in the overall cure rates calculated from studies employing the recommended doses for hookworm (78% in 68 studies: 92%, for A. duodenale in 23 studies and 75% for N. americanus in 30 studies), A. lumbricoides (95% in 64 studies), T. trichiura (48% in 57 studies), E. vermicularis (98% in 27 studies), S. stercoralis (62% in 19 studies), H. nana (68% in 11 studies), and Taenia spp. (85% in 7 studies).

Clomipramine is an antidepressant drug which was approved by FDA for the treatment of Obsessive-Compulsive Disorder. The exact mechanism of its action is unknown, however it is supposed that it may exert its effect by inhibiting serotonin reuptake.

Cetirizine, a human metabolite of hydroxyzine, is an antihistamine; its principal effects are mediated via selective inhibition of peripheral H1 receptors. It is indicated for the relief of nasal and non-nasal symptoms associated with seasonal or perennial allergic rhinitis, hay fever and chronic idiopathic urticaria. Commonly reported adverse reactions of cetirizine include headache, dry mouth and drowsiness or fatigue. Pharmacokinetic interaction studies with Cetirizine in adults were conducted with pseudoephedrine, antipyrine, ketoconazole, erythromycin and azithromycin. No interactions were observed.

Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Experimental data suggest that 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. Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular mooth muscle cells than on cardiac muscle cells. Amlodipine is indicated for the treatment of hypertension and coronary artery disease.

Famotidine, a competitive histamine H2-receptor antagonist, is used to treat gastrointestinal disorders such as gastric or duodenal ulcer, gastroesophageal reflux disease, and pathological hypersecretory conditions. Famotidine inhibits many of the isoenzymes of the hepatic CYP450 enzyme system. Other actions of Famotidine include an increase in gastric bacterial flora such as nitrate-reducing organisms. Famotidine binds competitively to H2-receptors located on the basolateral membrane of the parietal cell, blocking histamine affects. This competitive inhibition results in reduced basal and nocturnal gastric acid secretion and a reduction in gastric volume, acidity, and amount of gastric acid released in response to stimuli including food, caffeine, insulin, betazole, or pentagastrin.