The combination of verapamil and captopril in the treatment of essential hypertension.

A single-blind trial was carried out in 18 patients with moderately severe hypertension to investigate the efficacy of the angiotensin-converting enzyme inhibitor captopril in combination with the calcium antagonist verapamil after treatment with captopril alone had failed to achieve satisfactory control. For the first 2 weeks of the study, patients received 50 mg captopril twice daily, then 50 mg captopril plus 160 mg verapamil twice daily for 4 weeks, followed by 160 mg verapamil twice daily for a further 4 weeks. The double-dummy technique was used with placebo tablets given during the first and last treatment periods. Blood pressure and heart rate measurements in the supine and standing position were made at 2-week intervals throughout the study. Analysis of the results from the 13 patients who completed the trial protocol showed that the two drugs in combination produced significant reductions (p less than 0.01) in both supine and standing blood pressures compared with captopril alone, but a significant reduction (p less than 0.02) only in diastolic blood pressure compared with verapamil alone. Heart rate was not changed significantly throughout the study. Only 1 patient was withdrawn because of side-effects, although on questioning constipation, in particular, proved to be a problem in many.