Pantoprazole may enhance antiplatelet effect of enteric-coated aspirin in patients with acute coronary syndrome.

BACKGROUND: Antiplatelet therapy has proven beneficial in the treatment of cardiovascular disease. Proton pump inhibitors (PPIs) are commonly used for gastroprotection in patients receiving antiplatelet therapy. Several trials have been carried out to establish interactions between PPIs, clopidogrel and soluble formulations of aspirin, but no studies with PPIs and enteric-coated (EC) forms of aspirin have been conducted. The aim of this study was to assess if concomitant pantoprazole usage influences antiplatelet effect of EC aspirin in patients with acute coronary syndrome treated with percutaneous coronary intervention (PCI) and dual antiplatelet therapy. METHODS: Thirty-one consecutive patients were prospectively enrolled in the randomized, crossover, open-labelled designed study. The first 16 patients were given orally 40 mg of pantoprazole for the first four days while the next 15 subjects were treated with pantoprazole from the fifth to the eighth day of hospitalisation. Blood samples were collected at 6.00 a.m., 10.00 a.m., 2.00 p.m., and 7.00 p.m. on the fourth and eighth day of hospitalization. Aggregation in response to arachidonic acid was assessed in the whole blood on a new generation impedance aggregometer. RESULTS: Lower overall platelet aggregation in patients treated with pantoprazole (p < 0.03) was observed. When aggregation of platelets was analyzed separately at different times, the differences reached statistical significance six hours after the administration of pantoprazole and antiplatelet agents. The highest absolute difference in arachidonic acid-dependent aggregation was observed two hours after drug ingestion. CONCLUSIONS: Co-administration of pantoprazole may enhance the antiplatelet effect of enteric-coated aspirin in patients with acute coronary syndrome undergoing PCI.