Chronic effects of labetalol, pindolol, and propranolol on calf blood flow in intermittent claudication

To evaluate the role of beta-adrenoceptor blockade on lower limb circulation in patients with peripheral arterial disease, heart rate, blood pressure, calf blood flow and vascular resistance were measured at rest and during reactive hyperemia in seven patients with hypertension and intermittent claudication. The study was performed as a placebo-controlled, double-blind, crossover trial of 10 days with doses of propranolol, 80 mg twice a day, pindolol, 5 mg twice a day, labetalol, 200 mg twice a day, and labetalol, 400 mg twice a day as active drug. Heart rate was lowest during propranolol dosing and blood pressure was lowest during labetalol dosing irrespective of the labetalol dose used. The degree of peripheral arterial disease modulated the effect of beta-blockade on limb circulation. In the less symptomatic limbs, reactive hyperemic flow was greater after pindolol than after the other drugs and did not differ from the level recorded after placebo. These differences were inconsistent and small in the more symptomatic limbs. Thus as the peripheral arterial disease became more severe and extensive, beta-blockade, irrespective of its type, lost its hemodynamic effect on lower limb circulation.