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Calcium Channel Blockers

  • Definition

    Calcium channel blockers, also called calcium antagonists, are a newer category of medications which are used to treat heart disease and hypertension. They can slow the heart rate and relax blood vessels and they work by diminishing the flow of calcium between cells.


    Many patients with hypertension have benefited from calcium channel blockers. They are often prescribed for patients with coronary artery disease and are also used for heart rhythm abnormalities and hypertension.

    These drugs include nifedipine (Procardia, Adalat), diltiazem (Cardizem, Dilacor), verapamil (Calan, Verelan, Isoptin), nicardipine (Cardene), amlodipine (Norvasc), felodipine (Plendil), isradipine (DynaCirc), and several newer agents.

    The drugs attach to the surface membrane of the muscles in the artery wall and prevent calcium from entering. Without calcium, the muscles relax and the arteries dilate.

    The heartbeat is controlled by tiny electrical impulses, which explains why doctors use pacemakers to regulate heartbeat.

    Calcium plays a key role in regulating the heart's response to these electrical signals. It flows between the heart cells and surrounding fluid through a sort of chemical revolving door - the calcium channel. The more calcium that gets through the door before the electrical signal comes, the more strongly the heart contracts and the harder it works.

    Calcium channel blockers, like verapamil and its cousins, do not quite "lock" the revolving door, but they significantly slow it down. This eases the load on a damaged heart and, for many patients, improves heart functioning.

    For those who suffer from angina, calcium channel blockers have proved to be among the most effective medications ever discovered. They help the heart to work with less effort and, at the same time, relax the coronary arteries, improving the supply of oxygen-enriched blood of the heart itself. The result is almost as if the drug told the heart to sit back, relax, and take a few deep breaths.


    Do you recommend use of calcium channel blockers for my problem?

    Are there alternative drugs for controlling hypertension or angina?

    Which one should I take?

    Are there any special precautions that I should take?