Effect of a calcium antagonist: verapamil on resting blood pressure and pressor response to dynamic exercise

Effects of Verapamil, 120 mg t.i.d. in twenty-one hypertensive patients were assessed at rest and during dynamic exercise. The selection criterion was a diastolic blood pressure (DBP) found, at least 3 times, between 95 and 115 mmHg, not responding to placebo therapy. After 30 days of treatment with Verapamil, the resting systolic blood pressure (SBP) and DBP respectively decreased from 151.8 to 137.5 mmHg (p less than 0.001) and from 103.2 to 89.8 mmHg (p less than 0.001). The blood pressure (BP) and heart rate (HR) responses to dynamic exercise were also significantly blunted and the BP profile on effort was normalized in about half of the cases. Finally, the automatic recording of BP by a non invasive device showed a fall in the mean blood pressure (MBP) from 100.6 to 90.8 mmHg (p less than 0.001). The best results were obtained in patients with lower pretreatment plasma renin activity index and higher DBP or MBP automatically measured. The degree of response was not significantly related to age nor to plasma homovanillic acid level, which, however, significantly rose in all patients following therapy. This increase in sympathetic tone suggests a vasodilatory effect of Verapamil. The tolerance was good in all patients but four, whose electrocardiogram showed some alteration of atrio-ventricular conduction.