Calcium Channel Blockers

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton, Wajeeha Hassan and Kim Jackson  

Introduction[edit | edit source]

CCB in a cell membrane.

Calcium channel blockers work to decrease the amount of calcium that enters cardiac and smooth muscle cells. This is done by blocking voltage-gated calcium channels which results in dilation of blood vessels hence improving oxygen supply to the cardiac tissue.[1]

Calcium channel blockers (CCBs) are used in the management of hypertension, angina pectoris, supraventricular arrhythmias, subarachnoid hemorrhage, pulmonary hypertension, and for the prevention of migraine[2].

They work by preventing calcium from entering the cells of the heart and arteries. Calcium causes the heart and arteries to 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.

Mechanism Of Action[edit | edit source]

Calcium-channel blockers target L-type calcium channels and binds to them. These L-type calcium channels are located on the smooth muscle of vessels, cardiac myocytes, and nodal tissues in heart. These channels regulate the entry of calcium into muscle cells, which stimulates smooth muscle and cardiac myocyte to contract.Vasodilation occurs when calcium entry is blocked this way into cells. Hence there will be decrease in myocardial force generation (negative inotropy), decrease in heart rate (negative chronotropic), and decrease in conduction velocity within the heart (negative dromotropic).[3]

Indications[edit | edit source]

Following are the indications of calcium channel blockers however you should use them only when prescribed by your doctor.[4]

  1. Hypertension
  2. Arrhythmias
  3. Angina
  4. Pulmonary hypertension
  5. Subarachnoid hemorrhage
  6. Hypertrophic cardiomyopathy
  7. Coronary spasm
  8. Raynaud phenomena[5]

Categories[edit | edit source]

Conduction system.png

CCBs are often classify into two major categories, either non-dihydropyridines or dihydropyridines, based on their primary physiologic effects.

  1. The non-dihydropyridines have inhibitory effects on the sinoatrial (SA), and atrioventricular (AV) nodes resulting in a slowing of cardiac conduction and contractility. The are useful for the treatment of hypertension, reducing oxygen demand, and helps to control the rate in tachycardia.
  2. The dihydropyridines have a little direct effect on the myocardium, and instead, are more often peripheral vasodilators, and are useful for hypertension, post-intracranial hemorrhage associated vasospasm, and migraines.[6]
Dihydropyridines Non- Diyhydropyridines
Amlodipine Diltiazem (benzothiazepine)
Felodipine Verapamil (phenylalkamine)
Nicardipine
Nifedipine
Nimodipine
Nisoldipine
Isradipine

Adverse Effects[edit | edit source]

Ethanol blocks voltage-gated CC

Include:

  1. Non-dihydropyridines may cause constipation, worsening cardiac output, and bradycardia.
  2. Dihydropyridines may lead to lightheadedness, flushing, headaches, and peripheral edema.
  3. Alcohol, combined with a calcium channel blocker, can cause severe side effects and may also affect the way the medication works.

Physiotherapy[edit | edit source]

Exercising outdoor

Exercise Capacity: CCBs do not have a major effect on exercise capacity and may help people with angina better tolerate exercise. As a result of the blood vessels throughout the body dilating, blood flow into working muscles may be decreased and the lactate threshold (the point where lactic acid begins to build up in muscles) could be reached earlier, potentially affecting athletic performance.

Exercise capacity was seen to improve in patients with arterial fibrillation when calcium channel blockers were given.[7]

Other Exercise Effects: The non-dihydropyridines CCBs can reduce both resting and maximum heart rates and decrease heart rate response to exercise. They may also delay or prevent symptoms of myocardial ischemia, or reduced blood flow to the heart. For individuals using those medications, the American College of Sports Medicine recommends exercise testing to determine exercise heart rate. See Physical Activity and Exercise Prescription

References[edit | edit source]

  1. Elliott WJ, Ram CV. Calcium channel blockers. The Journal of Clinical Hypertension. 2011 Sep;13(9):687.
  2. Eisenberg MJ, Brox A, Bestawros AN. Calcium channel blockers: an update. The American journal of medicine. 2004 Jan 1;116(1):35-43.
  3. Shah K, Seeley S, Schulz C, Fisher J, Gururaja Rao S. Calcium channels in the heart: Disease states and drugs. Cells. 2022 Mar 10;11(6):943.
  4. Fisher M, Grotta J. New uses for calcium channel blockers. Drugs. 1993 Dec;46(6):961-75. 03
  5. McKeever RG, Hamilton RJ. Calcium channel blockers.
  6. McKeever RG, Hamilton RJ. Calcium channel blockers.
  7. Ulimoen, S.R., Enger, S., Pripp, A.H., Abdelnoor, M., Arnesen, H., Gjesdal, K. and Tveit, A., 2014. Calcium channel blockers improve exercise capacity and reduce N-terminal Pro-B-type natriuretic peptide levels compared with beta-blockers in patients with permanent atrial fibrillation. European heart journal, 35(8), pp.517-524.