Also found in: Dictionary, Thesaurus, Medical.
calcium-channel blocker,any of a class of drugs used in treating hypertensionhypertension
or high blood pressure,
elevated blood pressure resulting from an increase in the amount of blood pumped by the heart or from increased resistance to the flow of blood through the small arterial blood vessels (arterioles).
..... Click the link for more information. , angina pectorisangina pectoris
, condition characterized by chest pain that occurs when the muscles of the heart receive an insufficient supply of oxygen. This results when the arteries that supply the heart muscle with oxygenated blood are narrowed by arteriosclerosis.
..... Click the link for more information. , and certain arrhythmiasarrhythmia
, disturbance in the rate or rhythm of the heartbeat. Various arrhythmias can be symptoms of serious heart disorders; however, they are usually of no medical significance except in the presence of additional symptoms.
..... Click the link for more information. . They prevent the calcium ions needed for muscle contraction from entering the cells of smooth and cardiac muscle. This causes blood vessel walls to relax and blood to flow more freely to the heart, lowering blood pressure and relieving anginal pain. Some calcium-channel blockers, such as Procardia (nifedipine), slow the electrical impulses that run through heart muscle, thus regulating arrhythmias. Cardizem (diltiazem) is a common calcium-channel blocker.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/