Beta-adrenoceptor antagonists plus nifedipine in the treatment of chronic stable angina pectoris.

The antianginal effects of beta-adrenoceptor antagonists are achieved by a reduction in myocardial oxygen demand. This is a rational approach to treatment in patients whose angina is caused by a fixed stenosis. However, dynamic coronary vasospasm is an important factor in patients with chronic stable angina. Nifedipine increases myocardial oxygen supply by reducing coronary vascular tone and is a logical approach to treatment in these patients. For monotherapy of angina, nifedipine is less effective than the beta-adrenoceptor antagonists, but the combination has additive effects in reducing the frequency of anginal episodes and improving exercise tolerance. Plasma concentrations of nifedipine are closely related to clinical efficacy, and the variable first-pass metabolism of the drug leads to wide interindividual differences in peak concentrations and duration of action. Increasing the size of individual doses of nifedipine carries a risk of enhanced side effects due to high peak plasma concentrations. Optimal treatment may be more appropriately achieved in some patients by a slow release formulation, but with an increased frequency of administration.