Dose Effect of Clopidogrel Reloading in Patients Already on 75-mg Maintenance Dose

Background— Clopidogrel loading has mostly been studied in clopidogrel-naive patients. Whether clopidogrel-treated patients readmitted for an acute coronary syndrome or percutaneous coronary intervention can benefit from a new load of clopidogrel and at what dose remain unknown. Our aim was to evaluate the impact of 3 different strategies of administration of a loading dose of 900 mg clopidogrel in patients already treated with a maintenance dose of 75 mg clopidogrel for at least 7 days on residual platelet aggregation. Methods and Results— Patients treated long term by clopidogrel 75 mg/d were assigned to receive a first loading dose of 300, 600, or 900 mg clopidogrel and 4 hours later a second loading dose of 600, 300, or 0 mg, respectively, to achieve a total loading dose of 900 mg in all patients. Platelet aggregation was evaluated at baseline, at 4 hours after the initial load (and before second load), and at 24 hours using light transmission aggregometry with 20 μmol ADP and the point-of-care assay...