Calcium Channel Blockers

What are calcium channel blockers?

Calcium channel blockers are medicines that help relax the pressure in blood vessel walls. Examples are diltiazem, verapamil, nifedipine, and amlodipine. Which one is best for you depends on your condition and health.

When are calcium channel blockers used?

Calcium channel blockers are used to treat high blood pressure (hypertension), angina (chest pain caused by blockage of an artery in the heart), and some abnormal heart rhythms. They may be prescribed to treat Raynaud's phenomenon (a blood vessel problem) or to prevent migraine headaches. Calcium channel blockers may also be used to treat coronary artery disease (CAD) if you are at high risk for CAD. They may be used alone or in combination with other medicines.

How do calcium channel blockers work?

Calcium channel blockers slow the movement of calcium from the blood into the muscle cells of the blood vessels and heart. Muscle cells need calcium to be able to squeeze (contract). Getting less calcium relaxes the blood vessels. They open up and blood flows more easily through them. This helps lower blood pressure and the heart doesn't have to work as hard. Muscle cells in other parts of the body store their own calcium and don't depend on getting calcium from the blood.

What should I watch out for while taking this medicine?

Some calcium channel blockers may make angina worse. Angina is a feeling of tightness, squeezing, or pain in the chest. It happens when the heart does not get enough oxygen-rich blood. Calcium channel blockers may also cause the heart to beat too slowly. Talk with your healthcare provider about this.

For most people, the good effect of calcium channel blockers (lowering blood pressure) outweighs its bad effect of slightly reducing the heart's pumping ability. In other people, however, the reduced pumping of the heart causes heart failure. Heart failure is a condition in which the heart does not pump well enough to prevent the fluid buildup in body tissues. Some symptoms of heart failure are tiredness, swelling of the legs and ankles, and trouble breathing

Your healthcare provider will check your blood pressure and heart rate regularly while you are taking this medicine.

Do not eat grapefruit or drink grapefruit juice while taking a calcium channel blocker. Grapefruit affects the way this medicine works and may increase the risk of side effects.

When should I call my healthcare provider?

If you are taking calcium channel blockers, call your healthcare provider right away if:

• You notice increasing shortness of breath or swelling in your legs, feet, or ankles.
• You feel dizzy.

Other side effects to report to your healthcare provider include:

• constipation
• headache
• rash
• drowsiness
• flushing
• fast heartbeat
• nausea.

Written by Donald L. Warkentin, MD.
Published by RelayHealth.
© 2009 RelayHealth and/or its affiliates. All Rights Reserved.