Calcium antagonists and the second drug for hypertensive therapy.

Calcium antagonist monotherapy is more effective in older patients and in those with low plasma renin activity, whereas beta blockers control blood pressure better in younger patients and in those with normal or high renin activity. Monotherapy with a calcium antagonist has been shown to result in the reduction of diastolic blood pressure to equal to or less than 95 mm Hg in more than 80 percent of patients with essential hypertension. We investigated the antihypertensive efficacy of verapamil plus an angiotensin converting enzyme inhibitor and nifedipine plus a beta blocker in 24 patients (aged 41 to 68) with moderate to severe hypertension in whom monotherapy with a calcium antagonist had been ineffective. Blood pressure recorded in patients during the placebo period was 175 +/- 3/111 +/- 2 mm Hg (mean +/- SEM). Twelve patients received monotherapy with nifedipine (50.0 +/- 5.2 mg per day) and 12 others received verapamil (460 +/- 20 mg per day); neither treatment resulted in the reduction of diastolic blood pressure to less than 90 mm Hg. However, this goal was achieved when atenolol (89.5 +/- 25.7 mg per day) was added to the regimen of patients receiving nifedipine and enalapril (29.5 +/- 5.0 mg per day) was added to the regimen of those receiving verapamil; resultant blood pressures were 127 +/- 3/83 +/- 2 mm Hg and 137 +/- 5/85 +/- 1 mm Hg, respectively. It is suggested that in patients in whom hypertension is inadequately controlled by calcium antagonist monotherapy, counter-regulatory mechanisms can be blocked by the addition of a beta blocker or an angiotensin converting enzyme inhibitor to the calcium antagonist regimen, resulting in greatly improved, simple, well-tolerated, and safe control of blood pressure.