Effects of omeprazole or pantoprazole on platelet function in non-ST-segment elevation acute coronary syndrome patients receiving clopidogrel

BACKGROUND This study evaluated the effect of omeprazole or pantoprazole on platelet reactivity in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients receiving clopidogrel. METHODS Consecutive patients with NSTE-ACS (n = 620) from general hospital of Shenyang Military Command were randomized to the omeprazole or pantoprazole (20 mg/d) group (1:1), and received routine dual antiplatelet treatment. Patients' reversion rate of adenosine diphosphate-induced platelet aggregation (ADP-PA) was assessed at baseline, 12 to 24 h after administration of medication, and after 72 h of percutaneous coronary intervention (PCI). The primary endpoint of the study was platelet reactivity assessed with ADP-PA at 30 days after PCI. Adverse events (AEs) were recorded for 30-day and 180-day follow-up periods. RESULTS There were no significant differences between both the groups in platelet response to clopidogrel at 12-24 h after drug administration (54.09% ± 18.90% vs 51.62% ± 19.85%, P = 0.12), 72 h after PCI (52.15% ± 19.45% vs 49.66% ± 20.05%, P = 0.18), and 30 days after PCI (50.44% ± 14.54% vs 48.52% ± 15.08%, P = 0.17). The rate of AEs did not differ significantly between groups during the 30-day (15.2% vs 14.8%, P = 0.91) and 180-day (16.5% vs 14.5%, P = 0.50) follow-up periods after PCI. CONCLUSIONS The addition of omeprazole or pantoprazole to clopidogrel did not restrict the effect of platelet aggregation by reducing the conversion of clopidogrel. Compared with clopidogrel alone, pantoprazole-clopidogrel and omeprazole-clopidogrel combinations did not increase the incidence of adverse clinical events during 30-day and 180-day follow-up periods after PCI. TRIAL REGISTRATION The study is registered in the National Institutes of Health website with identifier NCT01735227. Registered 14 November 2012.