Comparisons of verapamil administration twice and three times daily in hypertension.

The antihypertensive effect of verapamil administered either two or three times daily was compared in a double blind, cross over study in 15 patients with mild to moderate essential hypertension. During the dose titration period with t.i.d. administration, normotension was obtained with daily doses of 240 mg in 7 patients, 360 mg in 7 patients and with 480 mg in one patient. Systolic and diastolic blood pressures (BP) in the supine (13/14 mmHg) and standing (14/14 mmHg) positions were significantly (p less than 0.001) reduced during the dose titration period. There was no statistically significant difference in the BP values between the twice and three times a day regimens. Five to 7-fold individual variations in the serum verapamil concentrations between individuals were observed. No significant correlations were found between serum drug concentrations and the change in mean arterial BP. There was no significant difference in the incidence of side effects between the two treatment regimens. Our results suggest that verapamil administered twice daily is effective in mild to moderate hypertension.