Does propranolol reduce plasma renin activity, plasma volume, and arterial pressure in patients with essential hypertension and hyper-reninemia on long-term diuretic therapy?
Propranolol effectively lowers blood pressure in diuretic-treated hypertensive patients, but this antihypertensive effect is not primarily mediated by the suppression of plasma renin activity or changes in plasma volume.
The influence of beta-adrenergic blockade (160 mg per day of propranolol for four weeks) on plasma renin activity, plasma volume, and arterial pressure was explored in 20 patients with essential hypertension with hyper-reninemia from long-term diuretic therapy. In 15 of these patients renin activity remained elevated (range, 3.1 to 23.0 ng per milliliter). Plasma volume was unchanged in eight, increased in 11 and reduced in one. In 17 subjects mean arterial pressure decreased by more than 10 mm Hg, but these impressive reductions could not be explained by quantitative changes in either renin activity (r equals 0.1) or plasma volume (r equals 0.1). These data suggest that suppression of plasma renin activity by beta-adrenergic blockade is not attainable during diuretic therapy and is not the major factor responsible for the antihypertensive action of propranolol.
Bravo et al. (1975) studied this question.