Lower limb haemodynamics during antihypertensive treatment with metoprolol and propranolol

In order to evaluate the role of beta 1-selective beta-adrenoceptor blockade on lower limb haemodynamics, blood pressure, leg blood flow and vascular resistance were measured at rest and during reactive hyperaemia in 34 hypertensive patients. The study was performed as a randomized double-blind cross over trial involving four weeks' treatment with the beta 1-selective metoprolol 100 mg b.i.d., the non-selective propranolol 80 mg b.i.d., and placebo b.i.d. Blood pressure was equally reduced by both beta-adrenoceptor blocking drugs. Reactive hyperaemic blood flow decreased by 19% (p less than 0.01) during propranolol and by 14% (p less than 0.01) during metoprolol treatment, when compared to placebo. Vascular resistance, however, was unaltered by these drugs. There were no significant differences between beta 1-selective and non-selective beta-blockade on lower limb haemodynamics in hypertensive patients. As the reason for diminished reactive hyperaemic blood flow we suggest a beta-blocking effect on the heart rather than a peripheral mechanism.