Vasodilatory Effects of Carvedilol and Pindolol

The effects of three different nonselective beta-blockers on central and peripheral hemodynamics as well as on pulmonary function were compared in 13 healthy subjects (19-37 years). The subjects were given carvedilol 50 mg, pindolol 10 mg, propranolol 80 mg, and placebo orally twice daily for 1 week in a double-blind, crossover, randomized manner. Heart rate, blood pressure, arterial calf blood flow (venous occlusion strain gauge plethysmography), and pulmonary function (flow-volume spirometry) were measured at the first and at the last trial day. Heart rate and blood pressure were lower on carvedilol and propranolol than on pindolol and placebo; the maximal bradycardiac effect was 13 and 17 beats/min and hypotensive effect 9/10 mm Hg and 10/7 mm Hg on carvedilol and propranolol, respectively. Both carvedilol and pindolol increased arterial flow by about 40% (p less than 0.05 and p less than 0.01, respectively) and reduced peripheral resistance by about 34% (p less than 0.05 and p less than 0.01, respectively), the effect persisting after 1 week of treatment. None of the medications had any noteworthy effects on pulmonary function. Two subjects complained of tremor on pindolol. We conclude that carvedilol and pindolol possess distinct vasodilatory properties. Carvedilol had a stronger hypotensive effect than pindolol and was well tolerated.