An inpatient trial of the safety and efficacy of losartan compared with placebo and enalapril in patients with essential hypertension.

The antihypertensive activity and safety of losartan, a specific and selective antagonist of angiotensin II (subtype 1) receptors, was evaluated in 100 inpatients with mild to moderate essential hypertension. After a 2-week, single-blind, out patient placebo lead-in period, the last 2 days of which included inpatient monitoring of baseline blood pressure, the patients were assigned randomly to receive once-daily doses of either placebo; 50, 100, or 150 mg losartan; or 10 mg enalapril. Patients were treated double blind for 5 days, followed by a day for the study of drug withdrawal. Beginning with the first dose, the three doses of losartan and enalapril significantly decreased peak and trough systolic and diastolic blood pressures compared with placebo (p < or = 0.05). The area under the blood pressure curve was analyzed as an assessment of total blood pressure change throughout the day. On day 1, total blood pressure reduction with losartan (50-150 mg) was slightly less than with enalapril. By day 5 of double-blind treatment, the reduction in blood pressure in these groups was similar, suggesting that losartan has a slower onset of action than enalapril. No rebound hypertension was observed after study-drug discontinuation. Losartan was well tolerated in this trial, with an adverse event profile similar to placebo and enalapril.