Can you describe what dipyridamole is?

Yes: Dipyridamole (dp-brand name persantine) is a platelet inhibitor and has been studied in conjunction with warfarin or coumadin. Dp acts to block the uptake of adenosine. In higher intravenous doses it causes vasodilation-specifically coronary vasodilation- and is therefore commonly used to perform pharmacological nuclear myocardial perfusion studies, commonly known as a nuclear stress test.

Its a antiplatelet: Its like a super Aspirin called Plavix (clopidogrel) taken to prevent clotting its an antiplatelet agent not an anticoagulant.