Cadralazine in combination with three different doses of atenololol in essential hypertension

The effects of the acute oral administration of cadralazine with atenolol at three different doses were studied in 12 patients with hypertension. The trial was divided into two phases according to a within patient, changeover design, with randomized and balanced sequences. During the first phase (two days) the effects of 15 mg of cadralazine were evaluated versus placebo according to a double-blind design. During the second phase (three days),the effects of 15 mg of cadralazine in combination with 12.5, 25, and 50 mg of atenolol were evaluated, according to an open-label design. In comparison with cadralazine, the combination of cadralazine plus atenolol induced a further decrease in blood pressure, which was significant with all doses of the beta-blocker. Moreover, the combination of cadralazine and 50 mg of atenolol demonstrated longer antihypertensive activity. All doses of atenolol, including 12.5 mg, were able to block the reflex heart rate increase observed during monotherapy with cadralazine.