Because Proton Pump Inhibitors lessen stomach acid, they may impact the absorption of some medications because the presence of stomach acid affects how well they are absorbed into the body. Namely, PPIs improve the absorption and concentration of digoxin while decreasing the absorption and concentration of ketoconazole (Nizoral) (Lanoxin). This could result in decreased ketoconazole efficacy and elevated digoxin toxicity.
Drug concentrations in the blood can rise as a result of proton pump inhibitors' ability to decrease the liver's ability to break down certain medications. Compared to the other Proton Pump Inhibitors, omeprazole (Prilosec) is more likely to impair the liver's ability to break down medications. For instance, omeprazole (Prilosec) may raise the blood levels of phenytoin, warfarin (Coumadin), and diazepam (Valium) (Dilantin). By preventing clopidogrel from becoming its active form, omeprazole (Prilosec, Prilosec OTC) lessens the impact of clopidogrel (Plavix). Avoid using this combo.
