Platelet Aggregation Inhibitory Effects and Pharmacokinetics of Prasugrel Used in Combination With Aspirin in Healthy Japanese Subjects

We evaluated the pharmacokinetics and pharmacodynamics of prasugrel used in combination with aspirin in healthy Japanese subjects. All subjects received aspirin 100 mg/day. Subsequently, in the single-administration study, 23 subjects also received prasugrel 20 mg or 30 mg; and in the multiple-administration study, 20 subjects received a loading dose of prasugrel 20 mg or 30 mg on day 1, followed by a maintenance dose of prasugrel 5 mg/day or 7.5 mg/day, respectively, on days 2–5. In both studies, the plasma concentration of the active metabolite of prasugrel, R-138727, reached a maximum at 0.5 h after administration, and rapidly decreased within 4 h. In the single-administration study, the inhibitory effect on adenosine diphosphate–induced platelet aggregation was significantly higher in the prasugrel 20 mg and 30 mg groups than in the placebo group at all time points (1–144 h) after administration. In the multiple-administration study, a similar antiplatelet effect was found after both the loading dose and the maintenance dose, and was maintained for 3–6 days after the last administration. There were study drug–related adverse events; however, all were mild, and none were clinically significant. This article is protected by copyright. All rights reserved