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tachyphylaxis

[tak-uh-fi-lak-sis]
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noun
  1. Medicine/Medical. immediate, temporary immunization against the effects of injection of a toxic extract owing to previous small injections of the same extract.
  2. a decreased response to a medicine given over a period of time so that larger doses are required to produce the same response.
Also tach·y·phy·lax·i·a [tak-uh-fi-lak-see-uh] /ˌtæk ə fɪˈlæk si ə/.

Origin of tachyphylaxis

tachy- + Greek phýlaxis a guarding, equivalent to phylak- (stem of phylássein to guard) + -sis -sis
Related formstach·y·phy·lac·tic [tak-uh-fi-lak-tik] /ˌtæk ə fɪˈlæk tɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for tachyphylactic

tachyphylaxis

noun
  1. very rapid development of tolerance or immunity to the effects of a drug

Word Origin

New Latin, from tachy- + phylaxis on the model of prophylaxis. See prophylactic
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

tachyphylactic in Medicine

tachyphylaxis

(tăk′ə-fĭ-lăksĭs)
n.
  1. Rapid desensitization to a pharmacologically or physiologically active substance, produced by inoculation with a series of small doses.
  2. A rapidly decreasing response to a drug following its initial administration.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.