A nurse is obtaining a medication history from a patient with gastroesophageal reflux disease. The patient claims to take omeprazole and warfarin at bedtime. The nurse should be concerned because:
•Omeprazole is a proton pump inhibitor that decreases gastric acid secretion. When combined with warfarin, omeprazole can actually prolong the elimination of warfarin and increase INR.
•Warfarin should be taken the same time every day, usually in the evening or at bedtime.
•Incorrect: Omeprazole should not be taken before meals. It should be taken daily before breakfast.
•Incorrect: Omeprazole has not been shown to cause encephalopathy when mixed with warfarin.
•Incorrect: Although omeprazole inhibits the absorption of many drugs, it does not inhibit warfarin absorption.