Omeprazole
From Ganfyd
rINN: Omeprazole
Other Names
bis(5-methoxy -2- [ [(4- methoxy -3,5- dimethyl -2- pyridinyl) methyl] sulfinyl] -1H- benzimidazole-1-yl), Losec ®, Prilosec ®
Pharmacological Information
Pharmacology Images
Web information on Omeprazole
Metabolism & Interactions
Omeprazole can inhibit the metabolism of phenytoin, warfarin and diazepam
- majority metabolised by CYP2C19 system forming hydroxy and desmethyl metabolites
- reminder by CYP3A4 forming sulphone metabolite
Mechanism of Action
Proton pump via the achiral sulphenamide which is produced in the parietal cell.
Other Issues for Omeprazole
Produces inhibition for almost a full day even though plasma half life less than 2 hours
Relevant Clinical Literature
UK Guidance
Regulatory Literature
Other Literature
Please read pharmacological data limitations
Other Wikis
Medpedia on Omeprazole (Less technical, good quality control)
Wikipedia on Omeprazole (Less technical, ? quality control)
Contents |
Introduction
The first and most popular world wide proton pump inhibitor. It is a racemic mixture and one enantiomer esomeprazole is still in patent.
Clinical Use
Indications
- NSAID associated peptic ulcers and erosions
- Gastro-oesophageal reflux disease (GORD)
- Acid-related dyspepsia
- Helicobacter pylori associated peptic ulcers
- Zollinger-Ellison syndrome
Administration
Oral
IV
Group Clinical Issues
Toxicity
Group Contra-indications
Group Cautions and Interactions
- There is now epidemiological evidence from two studies that all inhibit the actions of clopidogrel[1] when previously it was hoped the interaction was more specific. However clinically this interaction appears to be only significant for omeprazole and possibly esomeprazole.
- There is to date an unexplained association between use in the frail institutional elderly and mortality. As absolute annual mortality increased from 26.6% to 33.3% this may be due to confounding.
Group Side effects
- Hyponatraemia[2]
- Community acquired pneumonia[3]
- Hypomagnesaemic hypoparathyroidism (tetany)[4][5]
- Associated with increased risk of Clostridium difficile infection.[6][7]
Special advice
Don't measure gastrin levels if a patient is on a PPI (or at least do not panic when you get the result back !).
Pharmacology
see esomeprazole
References
- ↑ MHRA Drug Safety Update July 2009:2;12
- ↑ Rosholm JU, Nybo H, Andersen Ranberg K, Himmelstrup B, Skjelbo E, Christensen K, Gram LF. Hyponatraemia in very old nonhospitalised people: association with drug use. Drugs & aging. 2002; 19(9):685-93.
- ↑ Hauben M, Horn S, Reich L, Younus M. Association between gastric acid suppressants and Clostridium difficile colitis and community-acquired pneumonia: analysis using pharmacovigilance tools. International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases. 2007 Sep; 11(5):417-22.(Link to article – subscription may be required.)
- ↑ Epstein M, McGrath S, Law F. Proton-pump inhibitors and hypomagnesemic hypoparathyroidism. The New England journal of medicine. 2006 Oct 26; 355(17):1834-6.(Link to article – subscription may be required.)
- ↑ Cundy T, Dissanayake A. Severe hypomagnesaemia in long-term users of proton-pump inhibitors. . 2008 Jan 23.(Epub ahead of print) (Link to article – subscription may be required.)
- ↑ Anon. Proton pump inhibitors and Clostridium difficile: Clinical bottom line. Bandolier online. Last accessed 9 Oct 2006; based on 2003 review article.
- ↑ Dial S, Delaney JA, Barkun AN, Suissa S. Use of gastric acid-suppressive agents and the risk of community-acquired Clostridium difficile-associated disease. JAMA : the journal of the American Medical Association. 2005;294:2989-95. (Direct link – subscription may be required.)
