Pantoprazole is a proton pump inhibitor that inhibits gastric acid secretion and used for short-term treatment of erosive esophagitis associated with gastroesophageal reflux disease. Pantoprazole suppresses the final step in gastric acid production by covalently binding to the (H+, K+)-ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect leads to inhibition of both basal and stimulated gastric acid secretion, irrespective of the stimulus. The binding to the (H+, K+)-ATPase results in a duration of antisecretory effect that persists longer than 24 hours. Pantoprazole is used for short-term treatment of erosion and ulceration of the esophagus for adults and pediatric patients 5 years of age and older caused by gastroesophageal reflux disease. It can be used as a maintenance therapy for long-term use after initial response is obtained, but there have not been any controlled studies about the use of pantoprazole past a duration of 12 months. Pantoprazole may also be used in combination with antibiotics to treat ulcers caused by Helicobacter pylori. Use of pantoprazole may increase the chance of developing infections such as pneumonia, particularly in hospitalized patients.

Efavirenz (brand names Sustiva® and Stocrin®) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and is used as part of highly active antiretroviral therapy (HAART) for the treatment of a human immunodeficiency virus (HIV) type 1. For HIV infection that has not previously been treated, efavirenz and lamivudine in combination with zidovudine or tenofovir is the preferred NNRTI-based regimen. Efavirenz is also used in combination with other antiretroviral agents as part of an expanded postexposure prophylaxis regimen to prevent HIV transmission for those exposed to materials associated with a high risk for HIV transmission.

Rimantadine (INN, sold under the trade name Flumadine) is an orally administered antiviral drug used to treat, and in rare cases prevent, influenzavirus A infection. Rimantadine is an M2 ion channel inhibitor which specifically inhibits the replication of influenza A viruses by interfering with the uncoating process of the virus. M2 inhibitors block the ion channel formed by the M2 protein that spans the viral membrane (Hay 1985, Sugrue 1991). The influenza virus enters its host cell by receptor-mediated endocytosis. Thereafter, acidification of the endocytotic vesicles is required for the dissociation of the M1 protein from the ribonucleoprotein complexes. Only then are the ribonucleoprotein particles imported into the nucleus via the nuclear pores. The hydrogen ions needed for acidification pass through the M2 channel. The drug is effective against all influenza A subtypes that have previously caused disease in humans (H1N1, H2N2, and H3N2), but not against influenza B virus because the M2 protein is unique to influenza A viruses. Rimantadine is not active against the avian flu subtype H5N1 strains that have recently caused disease in humans.

Sumatriptan is a serotonin (5-HT1B/1D) receptor agonist indicated for acute treatment of migraine with or without aura in adults. Sumatriptan is structurally similar to serotonin (5-HT), and is a 5-HT receptor (types 5-HT1D and 5-HT1B) agonist. The specific receptor subtypes it activates are present on the cranial arteries and veins. Acting as an agonist at these receptors, sumatriptan reduces the vascular inflammation associated with migraines. The specific receptor subtype it activates is present in the cranial and basilar arteries. Activation of these receptors causes vasoconstriction of those dilated arteries. Sumatriptan is also shown to decrease the activity of the trigeminal nerve, which presumably accounts for sumatriptan's efficacy in treating cluster headaches. The injectable form of the drug has been shown to abort a cluster headache within 30 minutes in 77% of cases. Sumatriptan is effective for ending or relieving the intensity of migraine and cluster headaches. It is most effective taken early after the start of the pain. Injected sumatriptan is more effective than other formulations. Large doses of sumatriptan can cause sulfhemoglobinemia, a rare condition in which the blood changes from red to greenish-black, due to the integration of sulfur into the hemoglobin molecule. Serious cardiac events, including some that have been fatal, have occurred following the use of sumatriptan injection or tablets. Events reported have included coronary artery vasospasm, transient myocardial ischemia, myocardial infarction, ventricular tachycardia, and ventricular fibrillation (V-Fib).

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.

Clarithromycin is an antibacterial drug which is used either in combination with lansoprazole and amoxicillin (Prevpac), in combination with omeprazole and amoxicillin (Omeclamox) or alone (Biaxin) for the treatment of broad range of infections. The drug exerts its action by binding to 23s rRNA (with nucleotides in domains II and V). The binding leads to the protein synthesis inhibition and the cell death.

Esomeprazole strontium is a proton pump inhibitor. It suppresses gastric acid secretion by specific inhibition H+/K+ ATPase in the gastric parietal cell. The S- and R-isomers of omeprazole are protonated and converted in the acidic compartment of the parietal cell forming the active inhibitor, the achiral sulphenamide. By acting specifically on the proton pump, esomeprazole blocks the final step in acid production, thus reducing gastric acidity. The drug is indicated for the treatment of gastroesophageal reflux disease, reduction the risk of NSAID-associated gastric ulcer, eradication of H.pylori, and pathological hypersecretory conditions.

Nizatidine, chemically N-[2-[[[2- [(dimethylamino)methyl]-4-thiazolyl]methyl]thio]ethyl]-N’ -methyl-2-nitro-1,1-ethenediamine, is a histamine H2-receptor antagonist. Nizatidine reduced gastric acid secretion for up to 8 h suggesting that this compound could be used in with a once or twice daily dosage regime. Nizatidine was rapidly and well-absorbed orally, was widely distributed in tissues and the majority of the dose was excreted in the urine within 24 h. Nizatidine is indicated for duodenal and gastric ulcer as well as for the treatment of endoscopically diagnosed esophagitis, including erosive and ulcerative esophagitis, and associated heartburn due to gastroesophageal reflux 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.

Ipratropium (ipratropium bromide, ATROVENT® HFA) is a muscarinic antagonist structurally related to atropine but often considered safer and more effective for inhalation use. It is indicated for the maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema. Ipratropium (ipratropium bromide, ATROVENT® HFA) is an anticholinergic (parasympatholytic) agent which, based on animal studies, appears to inhibit vagally-mediated reflexes by antagonizing the action of acetylcholine, the transmitter agent released at the neuromuscular junctions in the lung. Anticholinergics prevent the increases in intracellular concentration of Ca2+ which is caused by interaction of acetylcholine with the muscarinic receptors on bronchial smooth muscle.