[Peripheral vascular effects of metoprolol, pindolol and propranolol in hypertensive patients]

Hemodynamic parameters, after administration of three different beta-blockers, were measured in fifteen hypertensive, and five normotensive, subjects. The non-invasive hemodynamic measurements were made prior to drug administration, after the first dose, and after prolonged treatment with either: metoprolol (M) 100 mg b.i.d., propranolol (Pr) 80 mg b.i.d., or pindolol (P) 10 mg b.i.d. With the parameters of blood pressure (B.P.), pulse rate (H.R.), blood flow in the leg at rest were determined with the plethysmographic impedance technique; venous compliance (V.C.), and flow in the leg after reactional hyperemia (F.R.H.) were evaluated by the mercury gauge technique. The pneumoplethysmographic technique was used to measure digital flow (D.F.). During administration of metoprolol, the B.P. and H.R. decreased significantly in the first few hours, and remained so during the prolonged treatment period of 4 weeks; the other parameters did not change significantly. Propranolol, after short-term treatment, decreased H.R. and blood flow in the leg at rest. Also, modifications in the venous compliance occurred but are difficult to interpret. After administration of pindolol, except for a decrease in H.R. and reactional hyperemia that occurred during the 2nd hour, no significant changes occurred in the other parameters. The digital flow showed non-significant variations. These preliminary results demonstrate that the changes registered through non-invasive techniques, although very small, affect pindolol less than metoprolol or propranolol.