the ratio between the dosage of a drug that causes a lethal effect and the dosage that causes a therapeutic effect.
Origin of therapeutic index
First recorded in 1925–30
Also called margin of safety.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Medicine definitions for 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.