Clinical experience with labetalol and enalapril in combination in patients with severe essential and renovascular hypertension.

Severe hypertension may be a difficult management issue, and it often requires therapy with multiple drugs at frequent dosing intervals. We report on the antihypertensive effects of the alpha-beta adrenergic blocking agent, labetalol, in combination with enalapril, a long-acting angiotensin-converting enzyme inhibitor, administered to 14 patients with severe hypertension (nine of whom had nephrosclerosis or renal artery stenosis) on other antihypertensive drug therapies. Blood pressure (BP), heart rate (HR), hematologic and blood chemistry values, and adverse side effects were monitored at 24 hours, 1 week, and 4 weeks of therapy. Rapid titration of the drugs was performed in the hospital in 10 patients; four were managed closely as outpatients. Following one month of combination therapy blood pressure decreased from 212 +/- 31/120 +/- 16 mm Hg at baseline to 155 +/- 19/86 +/- 12 mm Hg, and heart rate declined from 86 +/- 18 bpm to 70 +/- 16 bpm. Ten of the 14 patients (71%) maintained good BP control (BP less than 140/90 mm Hg) with no additional treatment. Serum potassium, creatinine, blood urea nitrogen concentrations, and hematologic parameters did not significantly change in 13 of 14 patients. Three patients developed symptomatic postural hypotension; in one patient this side effect resulted in discontinuation from the study. These data suggest that combination therapy with labetalol and enalapril is effective in lowering BP in patients with severe essential or renovascular hypertension. An additional advantage of this regimen is the twice-daily dosing interval, which may promote better long-term compliance.