November 17, 2009 – The U.S. Food and Drug Administration (FDA) today warned new safety information shows an interaction between the anti-clotting medication clopidogrel (Plavix) and the proton pump inhibitor (PPI) omeprazole (Prilosec/Prilosec OTC), used to reduce stomach acid.
The FDA said new data shows when clopidogrel and omeprazole are taken together, the effectiveness of clopidogrel is reduced. Patients at risk for heart attacks or strokes who use clopidogrel to prevent blood clots will not get the full effect of this medicine if they are also taking omeprazole, warned the FDA. Data showed separating the dose of clopidogrel and omeprazole in time will not reduce this drug interaction.
The FDA also said there are other drugs that are expected to have a similar effect and should be avoided in combination with clopidogrel. These include cimetidine, fluconazole, ketoconazole, voriconazole, etravirine, felbamate, fluoxetine, fluvoxamine, and ticlopidine.
Clinical studies showing PPIs may reduce the effectiveness of clopidogrel were first released more than a year ago. Today’s announcement was in response to new clinical data.
For more information: www.fda.gov/Safety/MedWatch
July 16, 2026 
