therapeutic index

noun Pharmacology.

the ratio between the dosage of a drug that causes a lethal effect and the dosage that causes a therapeutic effect.

Nearby words

  1. theralite,
  2. therapeutic,
  3. therapeutic abortion,
  4. therapeutic cloning,
  5. therapeutic crisis,
  6. therapeutic ratio,
  7. therapeutic virus,
  8. therapeutics,
  9. therapist,
  10. therapsid

Origin of therapeutic index

First recorded in 1925–30

Also called margin of safety. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Medicine definitions for therapeutic index

therapeutic index


The ratio between the toxic dose and the therapeutic dose of a drug, used as a measure of the relative safety of the drug for a particular treatment.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.