High clopidogrel loading dose during coronary stenting: effects on drug response and interindividual variability

Aim To assess platelet inhibitory effects, interindividual variability in platelet inhibition as well as response to a 600 mg, compared to a standard 300 mg, clopidogrel loading dose (LD) after coronary stenting Methods and results Platelet function profiles were assessed in 50 patients undergoing coronary stenting receiving either a 300 mg (n=27) or 600 mg clopidogrel LD. ADP (6 μM) and collagen (6 μg/mL) induced platelet aggregation, as well as ADP (2 μM) induced glycoprotein (GP) IIb/IIIa activation and P-selectin expression were assessed at baseline and 4, 24, and 48 h following clopidogrel front-loading. A more intense and rapid inhibition of platelet activation (both GP IIb/IIIa activation and P-selectin expression) were achieved using a 600 mg, compared to a 300 mg, LD throughout the entire 48 hours (p