Effects of propranolol therapy on renal function and body fluid composition.

Fourteen hypertensive men underwent assessment of renal function and body fluid composition following short-term (three to six weeks), long-term (five to six months), and withdrawal (two weeks) of propranolol hydrochloride monotherapy for the treatment of hypertension. Results indicate that propranolol had little effect on glomerular filtration rate (less than 10% decrease); changes that did occur were directly correlated with changes in effective renal plasma flow. Propranolol therapy decreased effective renal plasma flow 14% and renal blood flow 15% during long-term therapy; decreases in renal perfusion persisted following withdrawal of therapy. Propranolol therapy was neither antidiuretic nor antinatriuretic; propranolol had no effect on urine osmolality, free water clearance, sodium clearance, or fractional sodium excretion. Furthermore, propranolol therapy did not expand plasma volume, extracellular fluid volume, or total body water. Finally, propranolol therapy had no effect on the renal handling of potassium or on serum potassium concentration.