Definition of "beta-blocker" [beta-blocker]

• A drug, such as propanolol, that opposes the excitatory effects of norepinephrine released from sympathetic nerve endings at beta-receptors and is used for the treatment of angina, hypertension, arrhythmia, and migraine. Also called beta-adrenergic blocking agent. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "One type of drop, a form of beta-blocker, will “lower your heart rate, limiting your exercise capacity ….”"
• "Caveat: The number of adverse heart-rate responses may have been reduced because 39% of the patients were on beta-blocker medication, researchers said."
• ""Increase of 1-year mortality after perioperative beta-blocker withdrawal in endovascular and vascular surgery patients.""