The effects of slow-release verapamil on blood pressure and cardiovascular system in essential hypertension.

The study consisted of 26 patients (15 female, 11 male; mean age 43 +/- 10 years) with mild to moderate essential hypertension (EH). They were followed for a 2-week washout period and then for another 2-week single-blind placebo phase. Four patients receiving placebo dropped out of the study. Patients qualified for active medication if their sitting diastolic blood pressures (BPs), the median of three readings, were between 95 and 115 mm Hg at the end of the placebo period. Slow-release verapamil 240 mg was given once or twice daily as the sole antihypertensive agent and was continued for 6 weeks. Two patients (9%) were excluded from the trial due to early side effects. A target diastolic BP of less than 90 mm Hg was obtained in the remaining 20 patients. At the end of the study, the mean value of sitting BP was reduced from an initial 170/103 (125) mm Hg to 130/81 (98) mm Hg (p less than 0.001) and the mean standing BP was decreased from 167/103 (125) mm Hg to 130/81 (98) mm Hg (p less than 0.001). The drug had no significant effects on the laboratory data, left ventricular performance as assessed by echocardiography and systolic time intervals, and the electrocardiogram parameters with the exception of PR prolongation (p less than 0.05). Adverse effects were noted in only three patients (14%). We conclude that slow-release verapamil is an effective, safe, and well-tolerated drug in treating EH.