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Beta-blockers and calcium antagonists in angina pectoris. The potential role of combination therapy
1Department of Cardiology, Western Infirmary, Glasgow.
Insights
Combining beta-blockers and calcium antagonists improves antianginal efficacy in coronary heart disease. Certain combinations, like atenolol with nifedipine, show enhanced benefits without compromising cardiac function.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Beta-blockers limit heart rate and blood pressure increases during exercise.
- Calcium antagonists reduce myocardial oxygen demand.
- Combination therapy may enhance antianginal benefits by counteracting side effects.
Purpose of the Study:
- To evaluate the efficacy and safety of combined beta-blocker and calcium antagonist therapy for coronary heart disease.
- To compare combination therapy outcomes against monotherapy.
Main Methods:
- Review of studies investigating pharmacological combinations of beta-blockers and calcium antagonists.
- Assessment of antianginal efficacy through symptomatic and objective measures.
- Evaluation of effects on cardiac function, including cardiac output and left ventricular ejection fraction (LVEF).
Main Results:
- Combination therapy with propranolol and nifedipine, verapamil, or diltiazem showed greater antianginal efficacy than monotherapy.
- Atenolol combined with nifedipine did not adversely affect cardiac function or LVEF during exercise.
- Verapamil combined with atenolol led to a fall in resting ejection fraction, indicating potential cardiac deterioration.
Conclusions:
- Combination therapy, particularly atenolol with nifedipine, offers enhanced antianginal benefits in coronary heart disease.
- Careful selection of drug combinations is necessary to avoid adverse effects on cardiac function.
- Combination therapy may increase side effects, but some combinations can mitigate individual drug-induced side effects.
Abstract:
In coronary heart disease, beta-blockers are beneficial because they limit the increase in heart rate and blood pressure during exercise, and calcium antagonists are useful because they reduce myocardial oxygen demand. Many different pharmacological combinations of a beta-blocker and a calcium antagonist are possible, and beta-blockade may ameliorate reflex tachycardia induced by peripheral vasodilatation due to calcium antagonists, therefore enhancing the benefit. Studies have shown that combination therapy with propranolol and nifedipine, verapamil or diltiazem has greater antianginal efficacy based on symptomatic and objective assessment than either agent alone. A similar result has been reported for nifedipine or verapamil combined with atenolol. In combination, atenolol and nifedipine did not depress cardiac output or change the left ventricular ejection fraction (LVEF) at rest. During exercise atenolol alone resulted in a reduced LVEF response in most patients but the combination did not adversely affect left ventricular function. Nifedipine alone did not significantly change LVEF. When verapamil was combined with atenolol, resting ejection fraction fell, indicating a deterioration in cardiac function. Nifedipine and propranolol combined do not change heart rate significantly. Verapamil and atenolol both reduce resting heart rate and their combination has a greater effect; a combination of propranolol and diltiazem also reduces heart rate to a similar extent. Caution is therefore warranted when prescribing the latter 2 combinations. An increase in side effects can be expected with combination regimens compared with monotherapy; but with the nifedipine-atenolol combination the calcium antagonist can alleviate beta-blocker-induced effects by its vasodilator effect, and beta-blockers may ameliorate nifedipine-induced palpitations and flushing.(ABSTRACT TRUNCATED AT 250 WORDS)