Friday word: Tachyphylaxis

[med_cat]

tachyphylaxis [tak′ēfəlak′sis]

1 (in pharmacology) a phenomenon in which the repeated administration of some drugs results in a rapidly appearing and marked decrease in effectiveness.

2 also called mithridatism. (in immunology), a rapidly developing immunity to a toxin because of previous exposure, such as from previous injection of small amounts of the toxin (named for Mithridates VI who used the technique to survive an assassination attempt).

Etymology: Gk, tachys, rapid + phylax, guard

Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.

Further re: meaning #1: this was a new word from my reading this week; it is the same phenomenon that's called "tolerance" with narcotics, when applied to non-narcotic substances, such as sedatives, neuromuscular blocking agents (i.e., paralytics, incl. curare derivatives), etc.

Comments

[theidolhands.livejournal.com]

Ooh, good word. I didn't even know there was a word for this and I have experienced it too!

[med_cat]

I didn't know there was a word for it till the other day, myself...;) And yes, seen it happen many times.