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di-5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl]sulfinyl]-1H-benzimidazole | |
| Empirical formula | C34H36N6O6S2 |
| Molecular weight | 688.8 |
| Bioavailability (Oral) | 35-60% |
| Metabolism | hepatic CYP2C19, CYP3A4 |
| Elimination half life (Oral) | 0.5-1 hour |
| Excretion | 80% renal, 20% faecal |
| Pregnancy category | B3 (Australia) |
Omeprazole is a proton pump inhibitor used in the treatment of dyspepsia, peptic ulcer disease (PUD), GORD and Zollinger-Ellison syndrome. Omeprazole magnesium is marketed by AstraZeneca under the tradename Losec®, which is one of the most prescribed drugs in the United Kingdom and internationally.
Omeprazole is combined with the antibiotics clarithromycin and amoxicillin (or metronidazole in penicillin-hypersensitive patients) in the one week eradication triple therapy for Helicobacter pylori. Infection by H. pylori is the causative factor in the majority of peptic and duodenal ulcers.
It is interesting to note that the Losec® tablets are formulated as a "multiple-unit pellet system". Essentially, the tablet consists of enteric-coated granules (pellets) of the omeprazole formulation inside an outer shell. When the tablet is swallowed, the contents swell from water absorption, bursting the shell - releasing the tablet contents. The multiple-unit pellet system is often demonstrated to pharmacists and doctors by AstraZeneca sales representatives despite having little advantage, pharmacodynamically, over a regular enteric-coated tablet.
Adverse effects associated with omeprazole therapy are similar to those of the other proton pump inhibitors (cf. proton pump inhibitor page for full details).