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 ( = 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% 51.62% ± 19.85%,  = 0.12), 72 h after PCI (52.15% ± 19.45% 49.66% ± 20.05%,  = 0.18), and 30 days after PCI (50.44% ± 14.54% 48.52% ± 15.08%,  = 0.17). The rate of AEs did not differ significantly between groups during the 30-day (15.2% 14.8%,  = 0.91) and 180-day (16.5% 14.5%,  = 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.