Pharmacokinetics and pharmacodynamics of prasugrel in healthy Japanese subjects

This randomized double-blind and placebo-controlled study assessed the pharmacodynamics and pharmacokinetics of prasugrel in healthy adult Japanese male subjects after single (n = 50) and multiple (n = 40) oral administration. With a single administration of prasugrel (2-30 mg), the plasma concentration of the active metabolite increased rapidly, reached a maximum at 30 min after administration, and then decreased rapidly within 4 h. The 5 mg and higher doses prevented ADP-induced platelet aggregation in a dose-dependent manner. Further analyses showed that 30 mg prasugrel exhibited the peak inhibition, and 20 mg prasugrel showed a nearly equivalent effect. With multiple doses (2.5-10 mg), the pharmacokinetic parameters on Day 1 and Day 7 were similar, and no accumulation attributable to multiple dosing was observed. The inhibitory effect on ADP-induced platelet aggregation increased with doses from 2.5 to 7.5 mg, and reached the peak level at 7.5 mg. Regarding safety, all of the drug-related adverse events observed were mild, and there were no clinically significant bleeding-related adverse events. This study indicates that a single oral administration of prasugrel at a dose of up to 30 mg and a maintenance dose of up to 10 mg are tolerated in Japanese healthy subjects.