Calcium channel blockers: uses and side effects

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Amelia Willson 

Yael Cooperman, MD - Contributor Avatar

Reviewed by Yael Cooperman, MD, Ro, 

Written by Amelia Willson 

last updated: Feb 11, 2022

2 min read

Calcium channel blockers, or CCBs, are a group of blood pressure medications. These drugs are primarily used to treat high blood pressure and other issues like chest pain or arrhythmias (irregular heart rhythms). 

If you’ve been recommended CCBs and are wondering how they work, here’s what you need to know.


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What are calcium channel blockers?

CCBs are a group of medications used to treat high blood pressure or hypertension. Other conditions CCBs can treat include (Tocci, 2015; McKeever, 2021):

  • Angina (chest pain)

  • Irregular heartbeat

  • Coronary artery disease (blocked blood vessels around the heart)

  • Blood vessel conditions like Raynaud’s disease

  • Migraines 

Your healthcare provider will take many factors into account when selecting the best regimen to manage your blood pressure. Combining CCBs with other medications like ACE inhibitors or ARBs may be the most effective option. For example, studies have found taking CCBs with other blood pressure medications works better at treating hypertension in Black adults than ACE inhibitors or ARBs alone (Helmer, 2018).

CCBs can be short-acting (meaning you feel the effects quickly, but they last for a shorter time) or long-acting (the drug takes longer to kick in, but the effects last longer). CCBs are taken by mouth as dissolvable tablets or extended-release capsules.

How do calcium channel blockers work?

Calcium channel blockers work through two mechanisms. First, they make your heart relax a little bit so blood can flow more gently through your vessels. They also relax your blood vessels, which open them up. Together, these effects lower blood pressure (Elliott, 2011). 

Think of it like traffic on a highway: CCBs open additional lanes on the highway, making it wider and creating less traffic (or pressure) in the blood vessels.

Types of calcium channel blockers

There are two main types of calcium channel blockers: dihydropyridines and non-dihydropyridines.

Dihydropyridines are prescribed primarily to treat high blood pressure. Examples of these include:

  • Amlodipine (Norvasc)

  • Felodipine (Plendil)

  • Isradipine (DynaCirc)

  • Nicardipine (Cardene)

  • Nifedipine (Procardi, Adalat)

  • Nimodipine (Nymalize, Nimotop)

  • Nisoldipine (Sular)

  • Nitrendipine

Non-dihydropyridines can be prescribed to lower blood pressure or treat other issues like chest pain and irregular heartbeat (Humbert, 2017). These include:

  • Diltiazem (Cardizem, Dilacor, Tiazac)

  • Verapamil (Calan, Isoptin, Verelan)

Side effects of calcium channel blockers

Calcium channel blockers are considered safe and have proven to be effective for any age group (Caballero-Gonzalez, 2015). That said, it’s possible to experience side effects when taking this medication. Adverse reactions to CCBs include (Elliott, 2011):

  • ​​Constipation

  • Diarrhea

  • Dizziness

  • Dry mouth

  • Edema (swelling in the feet and lower legs)

  • Fast heartbeat

  • Fatigue

  • Flushing (redness in the face)

  • Gastroesophageal reflux disease (GERD) or heartburn

  • Headache

  • Low blood pressure

  • Nausea

  • Skin rash

What to know before taking calcium channel blockers

You need a prescription for CCBs. Tell your healthcare provider about your medical history, including any health conditions you have and all medications you are taking. This is important because CCBs can interact negatively with over-the-counter drugs and herbal supplements. For example, using CCBs with peppermint, ginkgo biloba, or St. John’s wort can cause side effects (Costache, 2019).

CCBs can also interact with certain foods and alcohol. A well-known one is grapefruit, which can interfere with your body’s ability to break down CCBs. This causes too much to stay in your system, leading to side effects (Costache, 2019). You may want to avoid drinking while on CCBs since alcohol affects blood pressure and heart rate (Tasnim, 2020)

Finally, follow your healthcare provider’s instructions for taking CCBs including the dose, when to take it, and whether you should take any other precautions.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

  • Caballero-Gonzalez, F. J. (2015). Calcium channel blockers in the management of hypertension in the elderly. Cardiovascular & Hematological Agents in Medicinal Chemistry , 12 (3), 160–165. doi:10.2174/1871525713666150310111554. Retrieved from

  • Costache, I. I., Miron, A., Hăncianu, M., Aursulesei, V., Costache, A. D., & Aprotosoaie, A. C. (2019). Pharmacokinetic interactions between cardiovascular medicines and plant products. Cardiovascular Therapeutics . doi:10.1155/2019/9402781. Retrieved from

  • Cunha, A. R., Umbelino, B., Correia, M. L., & Neves, M. F. (2012). Magnesium and vascular changes in hypertension. International Journal of Hypertension , 20. doi:10.1155/2012/754250. Retrieved from

  • Elliott, W. J. & Ram, C. V. (2011). Calcium channel blockers. Journal of Clinical Hypertension , 13 (9), 687–689. doi:10.1111/j.1751-7176.2011.00513.x. Retrieved from

  • Helmer, A., Slater, N., & Smithgall, S. (2018). A review of ACE inhibitors and ARBs in black patients With hypertension. The Annals of Pharmacotherapy, 52 (11), 1143–1151. doi:10.1177/1060028018779082. Retrieved from

  • Humbert, X., Roule, V., Milliez, P., & Alexandre, J. (2017). Verapamil and vasospastic angina: underuse in the elderly population. Journal of Geriatric Cardiology , 14 (7), 430–435. doi:10.11909/j.issn.1671-5411.2017.07.004. Retrieved from

  • McKeever, R. G. & Hamilton, R. J. (2021). Calcium Channel Blockers. [Updated Jul 25, 2021]. In: StatPearls [Internet]. Retrieved from

  • Tasnim, S., Tang, C., Musini, V. M., & Wright, J. M. (2020). Effect of alcohol on blood pressure. The Cochrane Database of Systematic Reviews, 7 (7). doi:10.1002/14651858.CD012787.pub2. Retrieved from

  • Tocci, G., Battistoni, A., Passerini, J., Musumeci, M. B., Francia, P., Ferrucci, A., et al. (2015). Calcium channel blockers and hypertension. Journal of Cardiovascular Pharmacology and Therapeutics , 20 (2), 121–130. doi:10.1177/1074248414555403. Retrieved from

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

February 11, 2022

Written by

Amelia Willson

Fact checked by

Yael Cooperman, MD

About the medical reviewer

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.