Effect of the new centrally acting antihypertensive agent rilmenidine on endothelial and platelet function in essential hypertension.

The aim of the study was to investigate the effect of therapy by rilmenidine on endothelial and platelet function in 23 patients with the early stages of untreated essential hypertension. The measurements were carried out before therapy, after 1 week of placebo administration, after 1 week, after 1 month and after 3 months of therapy. After 1 week of therapy both systolic (SBP) and diastolic blood pressure (DBP) were reduced (P < 0.001) all over the study period. Plasma thrombomodulin (TM) and von Willebrand factor (vWF) as indicators of endothelial dysfunction, and plasma beta-thromboglobulin (betaTG) as an indicator of in vivo platelet activation, were investigated. Fibrinogen as a risk factor for vascular changes was also assayed. Platelet aggregation without stimulation (spontaneous, SPA) and induced by adrenaline (APA) was measured. A decrease of plasma vWF level after 1 month (P < 0.05) and after 3 months (P < 0.05) of therapy was observed. We failed to find any changes of plasma TM and fibrinogen level. A reduction of platelet aggregation was evident after 1 week (SPA and APA, P < 0.05, respectively) but mainly after 1 month (SPA P < 0.01, APA P < 0.05) and after 3 months of therapy (SPA and APA, P < 0.01, respectively). It was accompanied by a decrease of plasma betaTG level after 3 months of therapy (P < 0.05). The vasculoprotective and antiplatelet effect of rilmenidine may be important in terms of the favourable role of antihypertensive drugs in cardiovascular morbidity.