Endralazine, a new peripheral vasodilator: absence of effect of acetylator status on antihypertensive effect.

50 patients with confirmed hypertension were treated with endralazine, a new peripheral vasodilator, in addition to the beta-blocker, pindolol, to which they had not responded adequately. The blood pressure was lowered from 173/115 mm Hg to 143/87 mm Hg in the 34 slow acetylators and from 175/111 mm Hg to 140/84 mm Hg in the 16 fast acetylators. The dosages of both pindolol and endralazine were the same in both groups. It is concluded that the acetylator phenotype does not affect the therapeutic efficacy or dosage requirement of endralazine. It is suggested that this is because endralazine is metabolised mainly by hydrazone formation and only to a minor extent by acetylation.

Endralazine, a new peripheral vasodilator. Evaluation of safety and efficacy over a 3 year period.

Nineteen out-patients with moderate to severe essential hypertension were treated daily for 3 years, with an average dose of 13 mg endralazine, a new peripheral vasodilator, in free combination with pindolol 3 x 5 mg. The blood pressure showed a statistically significant reduction from 172/110 mmHg to 154/92 mmHg after treatment for 3 years. Tachyphylaxis was not observed during the 3 years period. Oedema was the most frequent side-effect, but it disappeared spontaneously. No difference in efficacy and tolerance between slow and fast acetylators was found. Only 2 patients developed a weak positive antinuclear antibody titre, which disappeared spontaneously from one during continued treatment. No clinical evidence of a systemic lupus erythematosus-like syndrome was noted. It is concluded that the differences between endralazine and hydralazine in dosage and metabolism may explain the lower immunogenic activity of endralazine.