DIPYRIDAMOLE IS AN ADENOSINE REUPTAKE INHIBITOR AND PHOSPHODIESTERASE INHIBITOR WITH ANTIPLATELET AND VASODILATING ACTIVITY. DIPYRIDAMOLE HAS BEEN FOUND TO LENGTHEN ABNORMALLY SHORTENED PLATELET SURVIVAL TIME IN A DOSE-DEPENDENT MANNER. PERSANTINE DOES NOT INFLUENCE PROTHROMBIN TIME OR ACTIVITY MEASUREMENTS WHEN ADMINISTERED WITH WARFARIN. PERSANTINE IS A PLATELET ADHESION INHIBITOR, ALTHOUGH THEMECHANISM OF ACTION HAS NOT BEEN FULLY ELUCIDATED. THE MECHANISM MAY RELATE TOINHIBITION OF RED BLOOD CELL UPTAKE OF ADENOSINE, ITSELF AN INHIBITOR OF
PLATELET REACTIVITY, PHOSPHODIESTERASE INHIBITION LEADING TO INCREASED CYCLIC-3', 5'-ADENOSINE MONOPHOSPHATE WITHIN PLATELETS, AND INHIBITION OF THROMBOXANE A2 FORMATION, WHICH IS A POTENT STIMULATOR OF PLATELET ACTIVATION.