Haemodynamic effects of carvedilol, a new beta-adrenoceptor blocker and precapillary vasodilator in essential hypertension.

Carvedilol (BM 14190) is a new antihypertensive compound which combines beta-adrenoceptor blocking and precapillary vasodilating properties but is devoid of intrinsic sympathomimetic activity. The acute and long-term effects on blood pressure and regional haemodynamics (forearm plethysmography) were studied with carvedilol 25 mg b.i.d. or 50 mg b.i.d. Comparisons were made with propranolol 80 mg b.i.d. in a randomized double-blind placebo controlled trial comprised of 30 patients with essential hypertension. After a four-week placebo period active therapy was given for four weeks. Carvedilol administered acutely reduced blood pressure at both doses, delta 13/6 mmHg (P less than 0.001/P less than 0.01) and 17/10 mmHg (P less than 0.001/P less than 0.01). Resistance in the forearm fell significantly with the higher dose. This was in contrast to propranolol which only reduced heart rate acutely, and as expected caused a rise in forearm resistance. After four weeks both compounds had reduced blood pressure significantly and to the same extent. Blood flow was still significantly reduced with propranolol in contrast to the findings with carvedilol. We conclude that carvedilol given orally has a useful antihypertensive effect both acutely and during prolonged treatment. It is well tolerated and its haemodynamic profile is attractive.