Calcium channel blockers are drugs that block the entry of calcium into the cells of the heart and blood vessels walls by interacting with calcium channels. They are primarily used to treat hypertension, angina and arrhythmias. Learn about the different classes of calcium channel blocker medications and how they are used.
What are calcium channel blockers?
Calcium channel blockers, also called calcium antagonists, are a class of drugs that prevent the calcium from entering cells. They act on the cells of the heart and arteries. These drugs bind calcium channels and block the influx of calcium into the cells. The specific targets blocked by calcium channel blockers exist in high numbers on the cells of heart and blood vessels walls. Categories of calcium channels blockers
There are three classes of calcium channels blockers that differ in their chemical structure, their duration of action, the process by which they are eliminated from the body, and most importantly their relative selectivity towards cardiac versus vascular calcium channels. - Dihydropyridines, such as amlopidine, have high vascular selectivity and are therefore used to reduce systemic vascular resistance and arterial pressure. They are primarily prescribed for treating hypertension. - Non-dihydropyridines include phenylalkylamine and benzothiazepine. Phenylalkylamine, such as Verapamil, are relatively selective for myocardium and are often prescribed for treating angina and arrhythmias. Benzothiazepine, such as Diltiazem, are selective for vascular calcium channels and are therefore used to reduce arterial pressure.
For what conditions are calcium channel blockers used?
Calcium channel blockers are approved to treat hypertension, angina and arrhythmias.
What conditions do calcium channel blockers treat?
- Calcium channel blockers are used to treat hypertension by inducing smooth muscle relaxation. These drugs decrease systemic vascular resistance, which in turn lowers arterial blood pressure.
- The effect of these drugs on the angina derives from their vasodilatator and cardiodepressant actions. The combination of decreased oxygen demand and increased oxygen supply prevents angina.
- The anti-arrhythmic properties of calcium channel blockers are related to their ability to slow electrical conduction through the heart, thereby correcting abnormal rapid heartbeats. Calcium channel blockers are also used for treating pulmonary hypertension, Raynaud's phenomenon, cardiomyopathy, subarachnoid haemorrhage, and preventing migraine headaches.
In conclusion, there are different classes of calcium channel blockers, according to their selectivity towards cardiac versus vascular calcium channels, which determine their therapeutic indications. These drugs are primarily prescribed for treating hypertension, angina and arrhythmia.