Hemodynamic effects of cadralazine or chlorthalidone in verapamil-treated elderly hypertensives.

Fourteen hypertensives aged > 66-77 years, whose diastolic blood pressure (DBP) was > or = 95 mmHg at the end of 1-month treatment with verapamil 240 mg SR, took part in this clinical-hemodynamic study. Patients were randomized to add the long-acting hydralazine derivative, cadralazine, 10 mg once daily, or chlorthalidone 25 mg once daily for 1 month each, to their previous verapamil regimen, according to a double-blind crossover design. Echo-Doppler hemodynamics were performed before starting verapamil, 1 month after verapamil and then after each phase of the crossover study. A significant reduction in DBP both in supine and upright position was observed with both drugs, while the reduction in systolic blood pressure was not significant. Criteria for a satisfactory response were DBP < or = 90 mmHg or a DBP reduction > or = 10 mmHg; this goal was achieved in 9 patients with cadralazine, 9 patients with chlorthalidone, 5 patients with both. The hemodynamic study in responders showed that both cadralazine and chlorthalidone acted through a reduction of peripheral resistances without inducing reflex tachycardia. Thus, cadralazine and chlorthalidone represent a suitable second-step treatment in elderly hypertensives insufficiently controlled by verapamil monotherapy: both drugs act through a reduction in total peripheral resistance (TPR).