Effect of furosemide on the in vitro prostaglandin biosynthesis in human platelets.

Effect of furosemide at various concentrations (0.05-4 mM) was examined on the in vitro biosynthesis of prostaglandins in human platelets. At lower furosemide concentrations (0.05 and 0.1 mM) no effect was observed. At 1 and 2 mM concentrations, PGE2 significantly (P less than 0.01) increased. At 3 and 4 mM concentrations PGE2 increased though not significantly probably because of the small number of samples (n=5). A decrease in PGD2 formation was noted at 1-4 mM furosemide concentrations, though significantly only at 3 mM conc. At 1 and 2 mM concentrations, TxB2 and HHT increased whereas at 3 and 4 mM concentrations these metabolites were decreased. These effects were, however, not significant. No effect was observed on endoperoxide generation at 1 and 2 mM conc. Furosemide at 1 and 2 mM concentrations inhibited ADP- and arachidonic acid induced platelet aggregation. An increased platelet formation of PGE2 in the presence of furosemide may point to the fact that this drug shows its effect mainly on the formation of PGE2 which has been found to exert a profound effect on renal blood flow and thus ameliorates some forms of hypertension.