Effect of oral MK-421 and propranolol on the forearm arterial circulation in essential hypertension: a preliminary report

Abstract

The efficacy of MK-421 was compared with that of propranolol in patients with mild to moderate essential hypertension, using a placebo-controlled double-blind randomized protocol. The two drugs reduced supine and standing blood pressures, but propranolol, unlike MK-421, reduced heart rate. Using a pulsed Doppler method, brachial artery diameter, blood velocity and blood flow were measured during the study. These indices increased after MK-421 but were not modified after propranolol. Forearm vascular resistance decreased both after MK-421 and propranolol. Thus, chronic treatment with MK-421 or propranolol in hypertension lowers blood pressure but acts differently on forearm circulation. MK-421 dilates both the brachial artery and the arterioles of the forearm while propranolol has no effect on these arterial indices.