DRUG-INTERACTIONS WITH PROTON PUMP INHIBITORS

Omeprazole, lansoprazole and pantoprazole are all mainly metabolised b y the polymorphically expressed cytochrome P450 (CYP) isoform CYP2C19 (S-mephenytoin hydroxylase). All 3 proton pump inhibitors have a very limited potential for drug interactions at the CYP level. Small effect s on CYP reported for these compounds are usually of no clinical relev ance. No dose related adverse effects have been identified, suggesting that the small proportion of slow metabolisers is at no additional ri sk for clinically important drug interactions. The absorption of some compounds, e.g. benzylpenicillin (penicillin G), are altered during tr eatment with proton pump inhibitors as a result of the increased intra gastric pH. A synergy has been confirmed between omeprazole and amoxic illin or clarithromycin in the antibacterial effect against Helicobact er pylori.