Calcium channel blockers lower your blood pressure by preventing calcium from entering the cells of your heart and arteries. Calcium causes the heart and arteries to contract more strongly. By blocking calcium, calcium channel blockers allow blood vessels to relax and open.
Some calcium channel blockers have the added benefit of slowing your heart rate, which can further lower your blood pressure, relieve chest pain (angina) and control an irregular heartbeat.
Calcium channel blockers are also called calcium antagonists.
Examples of calcium channel blockers
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, others)
- Nifedipine (Adalat CC, Procardia)
- Nisoldipine (Sular)
- Verapamil (Calan, Verelan)
In some cases, your doctor might prescribe a calcium channel blocker with other high blood pressure medications or with cholesterol-lowering drugs such as statins.
When calcium channel blockers are used
In addition to high blood pressure, doctors prescribe calcium channel blockers to prevent, treat or improve symptoms in a variety of conditions, such as:
- Coronary artery disease
- Chest pain (angina)
- Irregular heartbeats (arrhythmia)
- Some circulatory conditions, such as Raynaud's disease
For black people and older people, calcium channel blockers might work better than other blood pressure medications, such as beta blockers, angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers.
Side effects of calcium channel blockers may include:
- Fast heartbeat (palpitations)
- Swelling in the feet and lower legs
Avoid grapefruit products while taking certain calcium channel blockers. Grapefruit juice interacts with the drug and can affect heart rate and blood pressure. This can cause symptoms such as headaches and dizziness.