Calcium channel blockers, or calcium antagonists, treat a variety of conditions, such as high blood pressure, migraines and Raynaud's disease. Find out more about this class of medication. By Mayo Clinic Staff

Calcium channel blockers prevent calcium from entering cells of the heart and blood vessel walls, resulting in lower blood pressure. Calcium channel blockers, also called calcium antagonists, relax and widen blood vessels by affecting the muscle cells in the arterial walls.

Some calcium channel blockers have the added benefit of slowing your heart rate, which can further reduce blood pressure, relieve chest pain (angina) and control an irregular heartbeat.

Some calcium channel blockers are available in short-acting and long-acting forms. Short-acting medications work quickly, but their effects last only a few hours. Long-acting medications are slowly released to provide a longer lasting effect.

Several calcium channel blockers are available. Which one is best for you depends on your health and the condition being treated.

Examples of calcium channel blockers include:

  • Amlodipine (Norvasc)
  • Diltiazem (Cardizem, Tiazac)
  • Felodipine
  • Isradipine
  • Nicardipine (Cardene SR)
  • Nifedipine (Procardia)
  • Nisoldipine (Sular)
  • Verapamil (Calan, Verelan, Covera-HS)

In some cases, your doctor might prescribe a calcium channel blocker along with other high blood pressure medications or with cholesterol-lowering drugs such as statins.

Doctors prescribe calcium channel blockers to prevent, treat or improve symptoms in a variety of conditions, such as:

  • High blood pressure
  • Chest pain (angina)
  • Brain aneurysm complications
  • Irregular heartbeats (arrhythmia)
  • Migraine
  • Some circulatory conditions, such as Raynaud's disease
  • High blood pressure that affects the arteries in your lungs (pulmonary hypertension)

Calcium channel blockers may not be as effective as diuretics, beta blockers or angiotensin-converting enzyme (ACE) inhibitors at lowering blood pressure. Because of this, calcium channel blockers aren't usually the first medication you'd be prescribed to lower your blood pressure.

However, for blacks, calcium channel blockers may be more effective than other blood pressure medications, such as beta blockers, ACE inhibitors or angiotensin II receptor blockers.

Side effects of calcium channel blockers may include:

  • Constipation
  • Headache
  • Rapid heartbeat (tachycardia)
  • Dizziness
  • Rash
  • Fatigue
  • Flushing
  • Nausea
  • Swelling in the feet and lower legs

Certain calcium channel blockers interact with grapefruit products. Check with your pharmacist or physician before taking a calcium channel blocker. Some calcium channel blockers can reduce your ability to eliminate calcium channel blockers from your body, allowing the medication to build up in your body. This buildup could cause serious side effects.

Feb. 01, 2014