[The vasodilator minoxidil in the treatment of hypertension]

A new vasodilating agent, minoxidil, was used in 17 patients with essential hypertension that had not responded sufficiently to combined treatment with 3 or 4 conventional hypotensive agents. After minoxidil was added, mean arterial BP dropped by 50 +/- 2.4 mmHg, the effect persisting for 3-4 months. Discontinuation of minoxidil after a short-term administration of 20 +/- 3.8 mg daily was accompanied with a BP rise eventually reaching baseline values, while gradual replacement with nifedipine after daily doses of minoxidil had been reduced smoothly over 3 or 4 weeks allowed to maintain mean arterial BP about 34 +/- 1.8 mm Hg below the baseline. The use of minoxidil in combination with beta-blockers and diuretics for 6 weeks resulted in a significant increase of left-ventricular myocardial weight, while cardiac contractility and pump function remained intact, as evidenced by electrocardiography. After 3 weeks of treatment, peripheral vascular resistance diminished in the forearm owing to reduced arterial and arteriolar tone, yet no reverse development of the vascular-wall adaptive structural changes could be seen at venous occlusion plethysmography.