Intravenous dilazep reduces blood pressure and peripheral vascular resistance in humans

Dilazep, a coronary vasodilating drug with adenosine-mediated activity, was tested (acute double-blind study versus placebo) for its antihypertensive activity in 12 patients who had mild to moderate hypertension. Dilazep (0.2 mg/kg body weight by IV infusion for ten minutes) significantly reduced systolic and diastolic blood pressure (random-zero sphygmomanometer) on average by 13.3 and 10.6 mm Hg respectively. The antihypertensive effect started rapidly, reached its maximum 20 minutes after administration, and lasted for 90 minutes. Heart rate significantly increased between 10 and 30 minutes. The antihypertensive effect of dilazep was associated with a relevant vasodilating effect as demonstrated by the changes in upper limb blood flow (strain-gauge plethysmography, +32%; P less than .001) and vascular resistance (-29%, P less than .001). The maximal reduction of vascular resistance was directly correlated to its baseline value. For these characteristics of action, at least in acute administration, dilazep would be useful agent for the treatment of high blood pressure in mild to moderately hypertensive patients.