[Vasoactive drugs with an effect on the prostaglandin system]

The balance between prostaglandin (PG)I2, a potent vasodilator and inhibitor of platelet aggregation mainly produced by endothelial cells, and thromboxane (TX)A2, a vasoconstrictor and inducer of platelet aggregation and adhesion synthesized predominantly by platelets, seems to be relevant for the regulation of vessel tone and platelet aggregation. PGE2 has vasodilating properties, too. Thus, substances affecting the biosynthesis of PG and TX may have prophylactic and therapeutic, but also detrimental effects with regard to hypertension and atherosclerosis. A mechanism of action which is related to the PG system is discussed for a number of antihypertensive agents, e.g. propranolol, angiotensin converting enzyme inhibitors, furosemide and cicletanine. The vasoprotective effect of inhibition of platelet cyclooxygenase by acetylsalicylic acid is well known. Calcium antagonists, dipyridamole, estradiol, aprotinin and interferon have also been reported to possibly exert beneficial effects on PG/TX levels, while cyclosporin A and streptokinase have shown undesirable interactions with the PG system.