Placebo-controlled, double-blind study of the effect of verapamil in intermittent claudication.

The clinical effect of verapamil was tested in 24 patients with intermittent claudication in a randomized, placebo-controlled, double-blind, crossover study. Slow-release verapamil or placebo was given for two periods of three weeks. The walking distance, systemic blood pressure, and ankle-brachial blood pressure index were measured. Furthermore, a possible change in peripheral vascular tone was provoked by hyperventilation. The walking distance rose after both verapamil (40%) and placebo (31%) (p less than 0.01 for both) but tended to increase only after verapamil (7%) as compared with placebo. Blood pressure fell equally after both verapamil and placebo (p less than 0.05 for both). Verapamil did not influence the ankle-branchial blood pressure index. No signs of vasoactivity in the lower extremities were seen after hyperventilation. Although the greatest individual improvements in walking distance were seen after verapamil administration, it was not possible to predict positive responders among the patients.