Calcium channel blockers are medications used to lower blood pressure. They work by increasing the flow of blood and oxygen to the heart. There are two types of calcium channel blockers that help treat conditions differently and may cause varying side effects.

Calcium is necessary for muscle contractions to occur throughout the body. This mineral enters muscle cells through ion channels, which are tiny pores on a cell’s surface.

This process is essential for typical bodily functioning.

Calcium channel blockers reduce the amount of calcium that can enter muscle cells in the heart and blood vessel walls through these channels. In doing this, they lower the pressure in the blood vessels and on the heart.

They are common medications that have a low risk of complications. This article discusses how these drugs work, as well as their uses and possible side effects.

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There are two different types of calcium channel blockers, known as dihydropyridines and nondihydropyridines.

amlodipine (Norvasc)verapamil (Calan, Isoptin)
felodipine (Plendil)diltiazem (Cardizem)
isradipine (DynaCirc)
nicardipine (Cardene)
nifedipine (Adalat, Procardia)
nimodipine (Nimotop, Nymalize)
nisoldipine (Sular)


Dihydropyridines target a specific type of calcium channel in the body. They cause the blood vessels to widen, lowering blood pressure.

It is sometimes possible for these medications to widen the blood vessels too much, resulting in swelling in the feet and legs. Doctors are careful to prescribe a dosage that reduces the risk of this happening.

Doctors may also minimize this risk by prescribing extended-release calcium channel blockers. The body absorbs this form of the drug over a longer period, which prevents the blood vessels from widening too much.


Nondihydropyridines widen blood vessels in the same way as dihydropyridines. However, they have additional effects on the heart that can help control a rapid heart rate.

Currently, there are only two nondihydropyridine medications.

Verapamil specifically targets heart muscle cells or the myocardium. Doctors use this drug to reduce chest pain because it relaxes blood vessels and reduces the amount of oxygen the heart requires.

Verapamil is also useful for slowing atypically rapid and potentially dangerous heart rhythms, such as supraventricular tachycardia.

Diltiazem is a medication for controlling heart dysrhythmias (rapid or irregular heart rhythms) and lowering blood pressure. In comparison with verapamil, it has a less significant effect on heart rate.

Doctors commonly use calcium channel blockers to treat high blood pressure. The medical term for high blood pressure is hypertension. This is a condition where the pressure within blood vessels is unusually high.

Elevated blood pressure (hypertension) can lead to stroke, heart disease, and heart attack.

Calcium channel blockers also have other possible uses, such as:

  • Chest pain (angina): Angina involves severe, tight pains in the chest due to drops in blood flow to the heart. Calcium channel blockers can reduce angina due to coronary artery spasms.
  • Coronary heart disease: Fatty buildups in blood vessels supplying the heart can reduce blood flow. This can cause coronary heart disease. When this occurs, calcium channel blockers can help to widen blood vessels, improving blood flow.
  • Irregular heartbeat (arrhythmia): In arrhythmia, the heart beats irregularly. It may beat too fast, too slow, or inconsistently.
  • Migraine: It is not clear what causes migraine attacks. Calcium channel blockers are not an approved treatment for migraine, but some doctors may prescribe verapamil as a preventive medication.

Scientists are currently exploring other potential uses for calcium channel blockers. For example, by reducing high blood pressure, they believe calcium channel blockers may also lower the risk of Alzheimer’s disease.

Common side effects of calcium channel blockers include:

Less commonly, these medications can cause:

The rarest side effects that occur with calcium channel blockers include:

If someone experiences any side effects from taking calcium channel blockers, they should see a doctor. If the side effects are causing serious problems, a doctor may change the prescription or reduce the dosage.

Beta-blockers slow heart activity by limiting the effects of stress hormones, such as epinephrine and norepinephrine. These medications are effective in lowering blood pressure.

Examples of beta-blockers include:

  • atenolol (Tenormin)
  • carvedilol (Coreg)
  • metoprolol (Lopressor)

Researchers have found that both beta-blockers and calcium channel blockers are effective in lowering blood pressure, making them useful treatments for various conditions that affect the heart, including angina and arrhythmia.

The American Heart Association recommends calcium channel blockers as a first-line pharmacological treatment for high blood pressure in most people and advises that beta-blockers should be a second-choice option.

However, a person’s doctor will work with their specific needs and consider other conditions to determine which option is best for them.

Angiotensin-converting enzyme (ACE) inhibitors are another type of medication for high blood pressure and various heart conditions. They relax blood vessels and make it easier for the heart to pump blood around the body.

ACE inhibitors work by blocking the enzymes that narrow blood vessels, which allows blood to flow through the vessels without putting as much pressure on them.

Examples of ACE inhibitors include:

  • lisinopril (Prinivil, Zestril)
  • enalapril (Vasotec)
  • benazepril (Lotensin)

They can cause some common side effects, such as a cough or skin irritation. In rare instances, ACE inhibitors can also cause angioedema, a potentially life threatening swelling of the lips, tongue, or mouth.

A doctor may sometimes prescribe an ACE inhibitor with a calcium channel blocker. A person’s doctor will work with them to determine whether an ACE inhibitor, a calcium channel blocker, or a combination of the two is best for their specific needs.

Calcium channel blockers are effective and widely used medications for treating high blood pressure and several heart conditions. They work by relaxing blood vessels and reducing pressure on the heart.

They can cause several side effects, such as fatigue and swelling in the abdomen, feet, and legs. Anyone who experiences worsening side effects should talk with a doctor about changing medication or reducing the dosage.

A range of alternative medications, such as ACE inhibitors and beta-blockers, are available for high blood pressure and heart conditions. They have a similar effect on the body, and doctors may prescribe a combination of these medications.