The hypotensive efficacies of two vasodilators, hydralazine and minoxidil, were assessed as these drugs were used individually in combination with beta-adrenergic blockade and diuretics in 11 hypertensive patients in whom elevated blood pressure had not been adequately controlled previously by other antihypertensive therapy. Control supine blood pressure fell from 191/128 mm Hg on propranolol and hydrochlorothiazide to 169/108 mm Hg on hydralazine, with a significantly greater reduction to

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... 2 mm Hg on minoxidil. Although sodium retention and tachycardia were controlled by the use of concomitant diuretics and beta-blockade, an increment in each of these drugs was occasionally required to prevent these complications. Renal function was changed little with the decrease in blood pressure. Plasma renin increased from a standing control of 14.5 mgg/ml/hr to 35.9 and 31.1 m,gg/ml/hr, respectively, on hydralazine and minoxidil. These data suggest the role of vasodilators used in combination with beta-blockers and diuretics and indicate the greater therapeutic efficacy of minoxidil. Additional Indexing Words: Antihypertensive therapy Propranolol Renin Aldosterone T HE USE OF drugs which lower blood pressure by direct dilation of the arterial bed appears to be a logical approach to the treatment of systemic hypertension. Such vasodilator drugs will reverse the elevated peripheral vascular resistance characteristics of hypertension without producing the side effects so frequently encountered with drugs that interfere with total adrenergic function.' In a previous study minoxidil, a new vasodilator, was shown to lower blood pressure effectively in hypertensive patients and to have a significantly greater effect when combined with beta-adrenergic blockade with propranolol.2 Beta-blockade itself has recently received considerable attention in the treatment of hypertension.3 4 However, the magnitude of the antihypertensive response with beta-blockade alone has been variable, with some investigators reporting effective control of hypertension using propranolol,5 while others have found minimal reductions using either pro-pranolol6 or newer beta-blocking drugs, alpre-nolol7 and practolol.8 In addition, propranolol has been found not to lower vascular resistance, and the observed hypotensive response appears to be the consequence of a reduction in cardiac output.6