Heart Health Heart Disease Treatment A Closer Look at Heart Medication Verapamil By Naveed Saleh, MD, MS Naveed Saleh, MD, MS LinkedIn Twitter Naveed Saleh, MD, MS, is a medical writer and editor covering new treatments and trending health news. Learn about our editorial process Updated on March 02, 2022 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Yasmine S. Ali, MD, MSCI Medically reviewed by Yasmine S. Ali, MD, MSCI Facebook LinkedIn Twitter Yasmine S. Ali, MD, MSCI, is a board-certified preventive cardiologist and lipidologist. Dr. Ali is also an award-winning writer. Learn about our Medical Expert Board Print Verapamil is a medication used to treat heart disease. It works by relaxing the blood vessels of the heart, as well as the blood vessels throughout the body. If you are prescribed verapamil, it's a good idea for you to familiarize yourself with the condition that you are being treated for, as well as the side effects of this medication. ERIKA CRADDOCK / SCIENCE PHOTO LIBRARY / Getty Images Mechanism of Action Verapamil is a calcium channel antagonist (blocker). Calcium promotes vascular muscle contraction, which narrows the blood vessels and increases pressure in the heart. Verapamil relaxes muscles that are located in the blood vessels by decreasing the entry of calcium ions through the L-type calcium channels that are located in these muscles. Verapamil has several effects: Vasodilation (widening) of coronary arteries (arteries that supply the heart muscle) and widening of arteries throughout the bodyDecreases intensity of heart contraction (heart pumping)Slows heart rate All of the different uses for verapamil are related to these effects. Metabolism Verapamil is absorbed in the intestines and approximately half of it is used or eliminated from the body in about eight hours. Clinical Uses Verapamil is indicated for the treatment of: Hypertension (high blood pressure), including malignant or refractory hypertension Arrhythmias (irregular heart rates) such as atrial flutter, atrial fibrillation, and supraventricular tachycardia Angina (chest pain), including stable angina, unstable angina, and Prinzmetal's Verapamil is also used off-label for treating certain conditions that are associated with muscle contraction of the blood vessels. A few of the off-label uses: Raynaud's phenomenon Migraine prophylaxis Cluster headache prophylaxis Adverse Effects and Drug Interactions The most frequent adverse effect of verapamil is constipation. For some people, verapamil can cause dizziness, light-headedness, and hypotension (low blood pressure). In cases of overdose, verapamil may interfere with heart rhythm, which can be fatal. Verapamil can interact with a wide variety of other drugs, including: Verapamil used with beta-blockers, nitrates, or diuretics can cause your blood pressure to fall dangerously low. Verapamil can interact with statins, which are used to treat high cholesterol. Verapamil can cause an increase in the concentration of statins in the body; thus, if you are already taking a statin, be sure to let your doctor know so your statin dose can be adjusted if needed. Verapamil is metabolized by the cytochrome P450 enzymes and the use of certain prescription medications like amiodarone (another antiarrhythmic) can interfere with P450, leading to verapamil toxicity. Grapefruit juice affects the P450 system and may increase verapamil blood concentrations. If you or a loved one is taking verapamil, it's important to be closely monitored by your prescribing cardiologist. Make appointments for regular check-ups with your cardiologist and be sure to inform them of any changes in your medication regimen—including any use of herbal medications. If you are feeling any adverse effects, like fainting, call for emergency help. Was this page helpful? Thanks for your feedback! Did you know the most common forms of heart disease are largely preventable? Our guide will show you what puts you at risk, and how to take control of your heart health. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 9 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Striessnig J, Ortner NJ, Pinggera A. Pharmacology of L-type Calcium Channels: Novel Drugs for Old Targets?. Curr Mol Pharmacol. 2015;8(2):110–122. doi:10.2174/1874467208666150507105845 National Center for Biotechnology Information. PubChem Database. Verapamil, CID=2520, https://pubchem.ncbi.nlm.nih.gov/compound/Verapamil Castell DO. Calcium-channel blocking agents for gastrointestinal disorders. Am J Cardiol. 1985;55(3):210B–213B. doi:10.1016/0002-9149(85)90633-2 Humbert X, Roule V, Milliez P, Alexandre J. Verapamil and vasospastic angina: underuse in the elderly population. 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"The Effect of Cytochrome P450 Metabolism on Drug Response, Interactions, and Adverse Effects" American Family Physician.