Dipyridamole. Molecular model of the drug dipyridamole (C24.H40.N8.O4). This drug, sold under the brand name Persantine, inhibits blood clot formation when given chronically and causes blood vessel dilation when given at high doses over a short time. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue) and oxygen (red).