Dipyridamole is a pyrimidopyrimidine that is 2,2',2'',2'''-(pyrimido[5,4-d]pyrimidine-2,6-diyldinitrilo)tetraethanol substituted by piperidin-1-yl groups at positions 4 and 8 respectively. A vasodilator agent, it inhibits the formation of blood clots. It has a role as a vasodilator agent, a platelet aggregation inhibitor, an adenosine phosphodiesterase inhibitor and an EC 3.5.4.4 (adenosine deaminase) inhibitor. It is a member of piperidines, a tetrol, a pyrimidopyrimidine and a tertiary amino compound.