Pharmacokinetic interaction of acetylsalicylic acid and dipyridamole

It is often recommended that acetylsalicylic acid (ASA) and dipyridamole should be given together in order to obtain secondary prophylaxis against certain ischaemic diseases. Therefore, the possible pharmacokinetic interactions between these agents were assessed following single-dose exposures in 14 healthy volunteers. The plasma concentrations of ASA, salicylic acid (SA) and dipyridamole were measured by selective h.p.l.c. techniques. It was found that, while dipyridamole kinetics were unaffected by concurrent ASA, concurrent dipyridamole significantly enhanced the peak concentration (24%) and AUC (27%) of ASA. Thus, co-administered dipyridamole might influence the anti-platelet effect of ASA.