Calcium channel blockers
Medically reviewed by Drugs.com. Last updated on Sep 16, 2021.
Calcium channel blockers are medications used to lower blood pressure. They work by preventing calcium from entering the cells of the heart and arteries. Calcium causes the heart and arteries to squeeze (contract) more strongly. By blocking calcium, calcium channel blockers allow blood vessels to relax and open.
Some calcium channel blockers can also slow the heart rate, which can further lower blood pressure. The medications may also be prescribed to 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. 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 (Procardia)
- Nisoldipine (Sular)
- Verapamil (Calan SR, Verelan)
Sometimes, a 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 being used to treat high blood pressure, a doctor also may prescribe calcium channel blockers to prevent, treat or improve symptoms of conditions, such as:
- Coronary artery disease
- Chest pain (angina)
- Irregular heartbeats (arrhythmia)
- Blood vessel conditions, such as Raynaud's disease
For blacks 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.