A Double-Blind Comparison of Amlodipine and Placebo Added to Open Enalapril in Patients with Moderate to Severe Essential Hypertension

The antihypertensive efficacy and tolerability of amlodipine in combination with enalapril were assessed in this two-center study. Patients with moderate to severe hypertension and with diastolic blood pressure > 95 mm Hg after 4 weeks of treatment with open-label enalapril 5-10 mg daily were randomized to receive amlodipine 10 mg daily or placebo, double-blind for a further 4 weeks, in combination with open-label enalapril. There were significantly larger falls in mean supine and standing blood pressure in patients treated with enalapril plus amlodipine than in those treated with enalapril plus placebo. There was no clinically or statistically significant difference between treatment groups in pulse rate, ECG, or body weight. Side effects were generally mild or moderate with a similar incidence in both treatment groups. The study showed once-daily amlodipine to be effective and well tolerated when administered as add-on therapy to enalapril.