Clinical evaluation of endralazine (BO22708), a new vasodilator, in essential hypertension.

In the treatment of severe hypertension the choice of vasodilator is limited by side-effects, of which the lupus erythematosus syndrome induced by hydralazine is potentially the most serious, particularly in patients with the slow acetylator phenotype. This study describes the clinical evaluation of a new vasodilator, endralazine, which is related to hydralazine but which is not metabolised to any great extent by acetylation. In 6 essential hypertensives not adequately controlled by combined beta-blocker and diuretic therapy the additional administration of the first dose of 10 mg endralazine resulted in a significant reduction in blood pressure, without orthostatic symptoms, but associated with significant increases in heart rate and plasma noradrenaline concentration. These 6 patients and a further 9 similar hypertensive patients were then prescribed twice daily endralazine for 4 weeks with significant improvement in blood pressure control. During this short period of maintenance treatment with endralazine the single dose observations were repeated and no significant changes in heart rate or plasma noradrenaline concentration were observed. In summary, endralazine is an effective vasodilator/antihypertensive which was well tolerated in a triple therapy regimen in this study.