Like HowStuffWorks on Facebook!

Calcium Channel Blockers

        Health | Heart

Calcium channel blockers are called CCBs for short. They are also called calcium channel antagonists. CCBs are the most widely prescribed medicines in the United States today. They can be used alone or in a combination pill with an ACE inhibitor./p>

When are calcium channel blockers prescribed?

In addition to treating those with high blood pressure, calcium channel blockers are also used for people who have heart disease. Because they allow the blood vessels that supply the heart to open wider, more oxygen-rich blood can get to the heart. They are also used to treat arrhythmias.


The following table lists some common brand and generic names for calcium channel blockers.

brand generic
Adalat CC nifedipine
Calan SR verapamil HCl
Cardene nicardipine HCl
Cardene SR nicardipine HCl
Cardizem CD diltiazem HCl
Cardizem SR diltiazem HCl
Covera-HS verapamil HCl
Dilacor XR diltiazem HCl
DynaCirc isradipine
DynaCirc CR isradipine
Isoptin SR verapamil HCl
Nimotop nimodipine
Norvasc amlodipine besylate
Plendil felodipine
Procardia XL nifedipine
Sular nisoldipine
Tiamate diltiazem HCl
Tiazac diltiazem HCl
Vascor bepridil HCl
Verelan verapamil HCl
Verelan PM verapamil HCl

How Calcium Channel Blockers Work

All cells in your body need calcium. The movement of calcium into the cells of the blood vessels causes them to narrow, or contract. Calcium channel blockers block some of this calcium so that the blood vessels relax and open wider. That action lowers the blood pressure. Also, when the blood vessels in the body become more relaxed, your blood flows more easily. This lessens the workload of your heart. Some calcium channel blockers reduce blood pressure and improve symptoms of heart disease by slowing the heart rate.

Precautions and Possible Side Effects

There have been recent concerns that some types of CCBs may be linked to an increase in heart attacks. This effect was said to be especially true in the elderly and those with coronary heart disease. However, only calcium channel blockers that need to be taken several times a day have been associated with this effect. The CCBs that only need to be taken once or twice a day do not appear to cause this problem. This is because they are released slowly into the bloodstream. If your doctor has prescribed a calcium channel blocker for you that must be taken more than twice a day, do not stop taking it. Talk with your doctor as soon as you can about the risks and benefits of this and any other medicine that you might be taking.

Precautions you should take if you are on calcium channel blockers: Talk with your doctor if you experience faintness or dizziness. Blood pressure medicines can occasionally cause dizziness. This is most likely to happen when you change position suddenly. But this may also be caused by other physical or medical problems that have nothing to do with your medicines.

Possible side effects of calcium channel blockers that you may notice:

  • dizziness or faintness
  • constipation
  • headache
  • nausea
  • palpitations or changes in the heart rate
  • swelling in the feet and ankles

Possible Drug Interactions With Calcium Channel Blockers

Before you take a calcium channel blocker, tell all your doctors and your pharmacist about all the medicines you take. Include medicines you take for your blood pressure as well as for any other problem. Tell them the names of everything you take and how much you take each day, including all of the following:

  • prescription medicines
  • over-the-counter medicines
  • herbs
  • vitamin and mineral supplements

It's best to keep an updated list of these and bring a copy to give to your doctor. That way you can add to it whenever you take something new or delete the types you no longer take. Make a copy for each of your doctors so that they can keep it in your file. This complete list helps your doctor be better prepared to prescribe a calcium channel blocker that is the least likely to interact with your other treatments.