Labetalol in the treatment of patients with hypertension and renal function impairment.

Labetalol has been used to treat patients with renal hypertension or hypertension in the presence of renal functional impairment. In some patients changes in the glomerular filtration rate (GFR) were followed during the treatment. Sixty patients were treated with labetalol for up to 24 months. Forty-nine of the patients were taking a diuretic and 23 were receiving additional antihypertensive therapy. The antihypertensive effect of labetalol has so far been assessed in 51 patients. Forty-six of these 51 patients have responded with a fall in the mean supine BP from 184/115 to 148/93 mmHg and the mean erect BP from 176/112 to 138/89 mmHg. The mean daily maintenance dose of labetalol for the responders was 418 mg (range 100-1200 mg). The majority of patients were controlled by less than 600 mg daily. Side-effects occurred in 38% of patients, the most serious of which was left ventricular failure in four patients with severe cardiac and renal disease. Other side-effects included transient postural hypotension, scalp tingling and problems with micturition. Fluid retention was frequent but was easily controlled with diuretics. In only three of 31 patients was there a fall in the GFR which could possibly be attributable to the treatment. These changes were small and not clinically significant. An improvement or stabilization of the GFR was noted frequently. Labetalol by intravenous infusion proved disappointing and quite unpredictable in its action. A large single oral dose was effective in hypertensive emergencies. Labetalol, preferably in combination with a diuretic, was a safe and effective drug for patients with hypertension and renal functional impairment.