Omeprazole
|
|
|
Missing image | |
| (RS)-5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl]sulfinyl]-1H-benzimidazole | |
| CAS number 73590-58-6 | ATC code A02BC01 |
| Chemical formula | C34H36N6O6S2 |
| Molecular weight | 688.8 |
| Bioavailability | 35-60% |
| Metabolism | hepatic CYP2C19, CYP3A4 |
| Elimination half-life | 0.5-1 hour |
| Excretion | 80% renal, 20% faecal |
| Pregnancy category | B3 (Australia) |
| Legal status | Schedule 4 (Australia) POM (UK) |
| Routes of administration | oral, intravenous |
Omeprazole is a proton pump inhibitor used in the treatment of dyspepsia, peptic ulcer disease (PUD), GORD and Zollinger-Ellison syndrome. It is marketed by AstraZeneca under the tradenames Losec and Prilosec, commonly as the magnesium salt omeprazole magnesium. Omeprazole is one of the most widely prescribed drugs internationally and is available over the counter in some countries.
Faced with the loss of patent protection and competition from generic manufacturers, AstraZeneca developed, launched, and heavily marketed esomeprazole (Nexium) , a single enantiomer form of omeprazole.
Clinical use
Main article: Proton pump inhibitor
Use in Helicobacter pylori eradication
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.
Multiple-unit pellet system
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, pharmacokinetically, over a regular enteric-coated tablet.