Dipyridamole (Persantine) is a phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells.

Trapidil is a vasodilator, is an antiplatelet drug with specific platelet-derived growth factor.

Ensifentrine is a PDE3/4 inhibitor, although its affinity for PDE3(IC50: 0.4 nM) is 3,440 times higher than that for PDE4(IC50: 1479 nM), that is under clinical development for the treatment of asthma and COPD and, potentially, cystic fibrosis.