Brands, Medical Use, Clinical Data
- Anti-ulcer Agents
- Proton-pump Inhibitors
Brands / Synonyms
Antra; Antra Mups; Audazol; Aulcer; Belmazol; Ceprandal; Danlox; Demeprazol; Desec; Dizprazol; Dudencer; Elgam; Emeproton; Epirazole; Erbolin; Esomeprazole; Esomeprazole Magnesium; Exter; Gasec; Gastrimut; Gastroloc; Gibancer; Indurgan; Inhibitron; Inhipump; Lensor; Logastric; Lomac; Losec; Mepral; Miol; Miracid; Mopral; Morecon; Nilsec; Nopramin; Ocid; Olexin; Omapren; Omebeta 20; Omed; Omegast; OMEP; Omepral; Omeprazol [Inn-Spanish]; Omeprazole [Usan:Ban:Inn:Jan]; Omeprazolum [Inn-Latin]; Omeprazon; Omeprol; Omesek; Omezol; Omezolan; Omid; Omisec; Omizac; OMP; Ompanyt; OMZ; Ortanol; Osiren; Ozoken; Paprazol; Parizac; Pepticum; Pepticus; Peptilcer; Prazentol; Prazidec; Prazolit; Prilosec; Prilosec Otc; Procelac; Proclor; Prysma; Ramezol; Regulacid; Result; Sanamidol; Secrepina; Tedec Ulceral; Ulceral; Ulcesep; Ulcometion; Ulcozol; Ulcsep; Ulsen; Ultop; Ulzol; Victrix; Zefxon; Zegerid; Zegerid with Magnesium Hydroxide; Zepral; Zimor; Zoltum
For the treatment of gastroesophageal reflux disease.
Omeprazole is a compound that inhibits gastric acid secretion and is indicated in the treatment of gastroesophageal reflux disease (GERD), the healing of erosive esophagitis, and H. pylori eradication to reduce the risk of duodenal ulcer recurrence. Omeprazole belongs to a new class of antisecretory compounds, the substituted benzimidazoles, that do not exhibit anticholinergic or H2 histamine antagonistic properties, but that suppress gastric acid secretion by specific inhibition of the H+/K+ ATPase enzyme system at the secretory surface of the gastric parietal cell. Because this enzyme system is regarded as the acid (proton) pump within the gastric mucosa, omeprazole has been characterized as a gastric acid-pump inhibitor, in that it blocks the final step of acid production. This effect is dose-related and leads to inhibition of both basal and stimulated acid secretion irrespective of the stimulus.
Mechanism of Action
Omeprazole is a proton pump inhibitor that suppresses gastric acid secretion by specific inhibition of the H+/K+-ATPase in the gastric parietal cell. By acting specifically on the proton pump, omeprazole blocks the final step in acid production, thus reducing gastric acidity.
Absorption is rapid, absolute bioavailability (compared to intravenous administration) is about 30-40% at doses of 20-40 mg.
Symptoms of overdose include confusion, drowsiness, blurred vision, tachycardia, nausea, diaphoresis, flushing, headache, and dry mouth.
Biotrnasformation / Drug Metabolism
Omeprazole delayed-release capsules are contraindicated in patients with known hypersensitivity to any component
of the formulation.
Omeprazole can prolong the elimination of diazepam, warfarin and phenytoin, drugs that are metabolized by
oxidation in the liver. Although in normal subjects no interaction with theophylline or propranolol was found, there
have been clinical reports of interaction with other drugs metabolized via the cytochrome P-450 system (e.g.,
cyclosporine, disulfiram, benzodiazepines). Patients should be monitored to determine if it is necessary to adjust
the dosage of these drugs when taken concomitantly with omeprazole.
Because of its profound and long lasting inhibition of gastric acid secretion, it is theoretically possible that
omeprazole may interfere with absorption of drugs where gastric pH is an important determinant of their
bioavailability (e.g., ketoconazole, ampicillin esters, and iron salts). In the clinical trials, antacids were
used concomitantly with the administration of omeprazole.
Combination Therapy with Clarithromycin
Co-administration of omeprazole and clarithromycin may result in increases in plasma levels of ompeprazole,
clarithromycin, and 14-hydroxy-clarithromycin.
Concomitant administration of clarithromycin with cisapride, pimozide, or terfenadine is contraindicated.
There have been reports of an intereaction between erythromycin and astemizole resulting in QT prolongation and
torsades de points. Concomitant administration of erythromycin and astemizole is contraindicated. Because
clarithromycin is also metabolized by cytochrome P450, concomitant administration of clarithromycin with astemizole
is not recommended.