The efficacy and duration of action of sustained-release verapamil in essential hypertension.

: The blood-pressure (BP)-lowering efficacy of sustained-release verapamil, using both clinic and ambulatory measurements, was assessed in patients with essential hypertension. In study 1, a between-patient comparison, we compared verapamil (n = 12) with propranolol (n = 10). Dosage of each agent was titrated to achieve optimal clinic BP control and this dose was maintained for the duration of the study. Both agents lowered clinic systolic and diastolic BP. Mean daily ambulatory BP was also reduced with propranolol by 23/8 mm Hg and with verapamil by 13/8 mm Hg. The mean percentage reduction of systolic BP was significantly greater with propranolol (p less than 0.01). In study 2 we assessed the duration of action of sustained-release verapamil (240 mg once daily) in 14 patients. Both clinic and mean ambulatory BP were significantly reduced by 17/12 and 16/8 mm Hg, respectively, and this reduction was maintained throughout the day. We conclude that this formulation of sustained-release verapamil is effective in lowering blood pressure in mild-to-moderate hypertension and that once-daily dosage with 240 mg maintains ambulatory BP reduction throughout the dosing interval.