Antihypertensive activity of verapamil: impact of dietary sodium. The VERSAL Study Group

Abstract

Objective: To define the influence of dietary salt intake on the antihypertensive effect of slow-release verapamil 240 mg once a day in a population with mild-to-moderate essential hypertension.

Design: Parallel, randomized, multicentre study.

Methods: Patients were advised to follow a moderately low salt diet (Low-salt group). After a 2-week run-in period, those patients with 24-h urinary sodium excretion (UNa) < or = 120 mmol/day and a diastolic blood pressure (DBP) between 90 and 114 mmHg were randomly assigned to verapamil + Low-salt or verapamil + unrestricted-salt diet (High-salt group) for 28 days. Compliance with diets was defined as Low-salt UNa < or = 120 mmol/day and High-salt UNa > 120 mmol/day with UNa increased by > or = 60 mmol/day over the level attained at the end of the run-in period.

Results: Significant reductions in mean systolic blood pressure (SBP) and DBP were found in both the Low-salt (n = 235) and High-salt (n = 183) groups. The therapeutic goal (DBP < 90 mmHg) was achieved in 38.3% of patients in the Low-salt and 44.8% of patients in the High-salt group. Office blood pressure results were confirmed by ambulatory 24-h blood pressure monitoring in a subsample of patients. Verapamil reduced mean blood pressure throughout the nycthemeral cycle without any significant difference between the two groups.

Conclusion: The restriction in sodium intake does not have an additive effect on the antihypertensive effect of the slow-channel calcium antagonist verapamil.