The effect of a novel 5HT₂ receptor antagonist sarpogrelate treatment on platelet function and fibrinolysis in Buerger's disease

The effect of a new, specific 5-HT₂ receptor antagonist sarpogrelate treatment on platelet function and fibrinolysis in Buerger's disease, was assessed in a pilot study. We investigated 10 patients suffering from Buerger's disease. Sarpogrelate in a dose of 3 × 100mg a day was given p.o. for a period of 8 weeks. It was well tolerated and no major side effects were noted. Sarpogrelate induced significant decrease in plasma serotonin concentration starting after 4th week which lasted through 8 weeks of the study, whereas plasma tryptophan concentration increased significantly after 2 and 4 weeks. There were no changes in plasma 5-HIAA concentration. On the other hand whole blood 5-HT concentration increased significantly alter 2 weeks, and there was also nearly significant increase in whole blood tryptophan concentration (p =0.052). Platelet aggregation induced by ADP and collagen did not show any statistically significant changes. Surprisingly, platelet aggregation induced by serotonin increased significantly after 2 weeks and even more so after 4 weeks of treatment and returned to baseline values after 8 weeks. Concentrations of tPA and PAI-1 did not change. There was also no effect, on platelet count, APTT, TT and fibrinogen concentration.