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Clinical use of calcium antagonists in hypertension: update 1986
1Section of Cardiology, University of Bergen, School of Medicine, Norway.
Insights
Calcium channel blockers effectively treat hypertension by reducing peripheral resistance without impacting cardiac output. They offer an alternative to other antihypertensives, especially for patients with co-existing conditions like angina or diabetes.
Area of Science:
- Cardiovascular Pharmacology
- Hypertension Management
Background:
- Calcium channel blockers (CCBs) offer a hemodynamic advantage in hypertension by reducing total peripheral resistance while maintaining cardiac output.
- Their efficacy is comparable to diuretics and beta-blockers in mild-to-moderate hypertension.
Purpose of the Study:
- To review the hemodynamic effects and clinical utility of calcium channel blockers in hypertension management.
- To compare CCBs with other antihypertensive classes regarding efficacy, metabolic effects, and side effect profiles.
Main Methods:
- Review of clinical data for verapamil, diltiazem, and nifedipine.
- Analysis of hemodynamic effects, including peripheral resistance, cardiac output, and heart rate.
- Evaluation of efficacy and safety in various patient populations and co-morbidities.
Main Results:
- CCBs reduce peripheral resistance and maintain blood flow, even during exercise.
- Verapamil and diltiazem cause minor heart rate reduction offset by increased stroke volume and prolong AV conduction.
- CCBs do not adversely affect glucose, uric acid, or potassium levels, nor blood lipids.
Conclusions:
- Calcium channel blockers are effective antihypertensives, particularly beneficial in patients with hypertension and angina, peripheral vascular disease, COPD, or diabetes.
- Dihydropyridines can be combined with beta-blockers; verapamil/diltiazem combinations with beta-blockers should be avoided due to bradycardia risk.
- While effective, long-term data on morbidity and mortality compared to other agents are still limited.
Abstract:
From a hemodynamic point of view, the calcium antagonists represent an interesting way of treating hypertension, because they reduce total peripheral resistance without compromising cardiac output. Blood flow is also maintained during muscular exercise. Verapamil and diltiazem induce slight reduction in heart rate, but this is compensated by increase in stroke volume. Verapamil and diltiazem also prolong atrioventricular conduction time, in contrast to the dihydropyridines. Most clinical data are available for verapamil, diltiazem, and nifedipine. In patients with mild-to-moderate hypertension, these compounds seem as effective as diuretics and beta-blockers. They do not induce disturbances in glucose metabolism, serum uric acid, or serum potassium, and unwanted disturbances in blood lipids have not been described. The dihydropyridines may safely be combined with beta-blockers, but the combination of either verapamil or diltiazem with a beta-blocker should be avoided (because of the high risk of bradycardia). The calcium antagonists seem particularly useful in patients with the combination of hypertension and angina pectoris or peripheral vascular diseases or chronic obstructive lung diseases or diabetes. They are also effective in hypertensive crises. They may also be tried as a first line drug in patients with mild and moderate essential hypertension, particularly when diuretics or beta-blockers are contraindicated. Temporary side effects due to vasodilatation (headache, flushing, and palpitations) are seen frequently, particularly on the dihydropyridines. Edema is the most frequent serious side effect of the dihydropyridines, and constipation is most common with verapamil. At this point, few long-term data are available and it is not known whether the calcium antagonists will give better or worse results, with respect to morbidity and mortality, than the beta-blockers, diuretics, or other more recent antihypertensive agents.