Effect of oral penbutolol on renal haemodynamics of hypertensive patients with renal insufficiency.

Acute or chronic administration of most beta-adrenoreceptor blocking drugs is associated with a fall in renal blood flow and glomerular filtration rate. In patients with renal insufficiency this effect on renal function may be clinically important. Penbutolol is a non-cardioselective, pure laevo, beta-blocker with intrinsic sympathomimetic activity. Previous studies have suggested that penbutolol may increase the glomerular filtration rate. In this study eight hypertensive patients with renal insufficiency were studied during a three-week placebo period and then for four weeks while taking penbutolol in a dose of 40 or 80 mg daily. Penbutolol produced a fall in the pulse rate in all eight patients. Five of the eight patients had a fall in their supine and standing blood pressure. Effective renal plasma flow and glomerular filtration rate did not change significantly. In seven of the eight patients there was a fall in the calculated renal vascular resistance but the mean fall did not reach statistical significance. Penbutolol appears to be an effective beta-blocker and one that could be used appropriately in patients with renal insufficiency.