[On the metabolism of prasugrel].

We read with interest the editorial by Drs. Freedman and Iafrati recently published in Revista Española de Cardiologı́a. The editorial mentions that prasugrel is an inhibitor of the P2Y12 receptor, that it is not metabolized in the liver, and that it does not appear to be affected by the variability of isozyme P450. We believe that it might be a good idea here to indicate the pharmacokinetic characteristics of prasugrel. Prasugrel (CS-747, LY-640315) is a third generation, orally administered thienopyridine that acts as a specific and irreversible antagonist of the 5’-diphosphate (ADP) P2Y12 receptor, and which needs to be metabolized for it to exert its effect. The initial molecule, prasugrel, is rapidly hydrolyzed by intestinal and blood esterases to the metabolite thiolactone (R-95913) (Fig. 1). Thus, prasugrel is not detected in the plasma. Via the action of