therapeutic index

noun

: a measure of the relative desirability of a drug for the attaining of a particular medical end that is usually expressed as the ratio of the largest dose producing no toxic symptoms to the smallest dose routinely producing cures

Examples of therapeutic index in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
It is known as a narrow therapeutic index (NTI) drug. Karen Berger, Pharmd, Verywell Health, 20 Feb. 2025 The risk of lithium toxicity, given the narrow therapeutic index, is why patients on lithium are closely monitored. Lydia Wang, refinery29.com, 24 June 2021 The therapeutic index gives you the window in which the drug will be effective against the virus without causing undue side effects. William A. Haseltine, Scientific American, 1 Oct. 2020 Many antibiotics have a sufficiently high therapeutic index to allow for a single dose to be used. Richard Klasco, New York Times, 8 June 2018 Because these trials are a mandatory step in the Food and Drug Administration approval process, each drug’s therapeutic index is well defined. Richard Klasco, New York Times, 8 June 2018 The therapeutic index is the ratio of a drug’s efficacy to its toxicity. Richard Klasco, New York Times, 8 June 2018

Word History

First Known Use

1926, in the meaning defined above

Time Traveler
The first known use of therapeutic index was in 1926

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Cite this Entry

“Therapeutic index.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/therapeutic%20index. Accessed 4 Mar. 2025.

Medical Definition

therapeutic index

noun
: a measure of the relative desirability of a drug for the attaining of a particular medical end that is usually expressed as the ratio of the largest dose producing no toxic symptoms to the smallest dose routinely producing cures

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