Peripheral hemodynamic effects of short-term nadolol administration in essential hypertension

A study of forearm arterial and venous hemodynamics by pulsed Doppler velocimetry and plethysmography was performed in 21 patients with essential hypertension, aged 16 to 54 years, before and after short-term nadolol administration at a dose of 0.05 mg/kg. Because of a large intersubject variability in the responses of the hemodynamic parameters to nadolol, an unconventional statistic approach was used to divide the overall population of patients into two homogeneous groups. The first included nine patients (group 1) and the second 12 patients (group 2). In patients of group 1, nadolol significantly decreased the systolic blood pressure (p less than 0.001), venous tone (p less than 0.01), and brachial artery flow (p less than 0.05). In patients of group 2, nadolol did not affect any forearm parameters. Each group of patients was compared to an age- and pressure-matched group of patients receiving propranolol at equiblocking doses. Contrary to nadolol, propranolol was found to increase significantly the forearm vascular resistance in patients of groups 1 and 2 (90 +/- 19%, p less than 0.001; 63 +/- 10%, p less than 0.001, respectively). Thus the hemodynamic beta-blocking effects of nadolol in the forearm were less marked than those of propranolol, suggesting that the effects of acute beta blockade by nadolol could be offset by other effects, such as a peripheral partial-agonist effect.