A randomised, placebo-controlled, double-blind, crossover study of losartan and enalapril in patients with essential hypertension

Abstract

The primary objective of this randomised, placebo- controlled, double-blind, crossover study, was to evaluate and compare the longer term effects of the angiotensin II type 1 receptor antagonist losartan and the converting enzyme inhibitor enalapril on 24-h ambulatory blood pressure (BP). After a 4-week placebo run-in period, nine patients with essential hypertension entered the double-blind phase of the study, which consisted of three 6-week periods during which patients were treated with placebo, enalapril 20 mg o.d. or losartan 50 mg o.d. Losartan and enalapril, taken between 07.00 and 08.00, reduced ambulatory BP throughout the 24-h period. Average night time BP was reduced from 133/85 mm Hg on placebo to 124/78 mm Hg on enalapril and to 126/77 mm Hg on losartan. Daytime BP averaged 157/101 mm Hg on placebo, and was significantly lower during enalapril (142/91 mm Hg) than during losartan treatment (147/95 mm Hg). Clinic BP, measured 2 to 4 hours after drug intake, was reduced to the same extent by both drugs. The losartan-induced BP changes were significantly related to those obtained with enalapril (0.63 < r < 0.93). Ambulatory BP monitoring was repeated after 4 weeks of combined therapy in six patients. The BP lowering effect of the combination was not significantly better than that achieved with enalapril alone. In conclusion, losartan 50 mg o.d. and enalapril 20 mg o.d. lower BP to approximately the same extent, except for a more pronounced effect of enalapril on daytime ambulatory BP. The current study does not provide convincing evidence that addition of losartan to enalapril in the doses used further reduces BP.