Protective index: Difference between revisions

Revision as of 14:23, 28 January 2024

Latest revision as of 19:07, 27 May 2025

(One intermediate revision by one other user not shown)

Line 5:

The protective index is similar to the [[therapeutic index]], but concerns toxicity ([[TD50|TD₅₀]]) rather than lethality ({{LD50}}); thus, the protective index is a smaller ratio. Toxicity can take many forms, as drugs typically have multiple side effects of varying severity, so a specific criterion of toxicity must be specified for the protective index to be meaningful. Ideally a choice is made such that the harm caused by the toxicity just outweighs the benefit of the drug's effect. Thus, the protective index is a more accurate measure of the benefit-to-risk ratio than the therapeutic index, but is less objectively defined. Nevertheless, the therapeutic index can be viewed as an [[upper bound]] to the protective index for a given substance.

Protective index can also defined as the factor by which the dose of a toxicant must be multiplied to produce a defined level of toxicity in the presence of a nontoxic dose of another chemical.<ref name="Bhat et al. 2007">{{cite journal |lastlast1=Bhat |firstfirst1=A. Shakoor |last2=Ahangar |first2=Azad A. |date=2007-02-03 |title=Methods for Detecting Chemical–Chemical Interaction in Toxicology |url=http://www.tandfonline.com/doi/full/10.1080/15376510601177654 |journal=Toxicology Mechanisms and Methods |language=en |volume=17 |issue=8 |pages=441–450 |doi=10.1080/15376510601177654 |pmid=20020870 |issn=1537-6516|url-access=subscription }}</ref>

<math>\mbox{Protective index} = \frac{\mathrm{LD}_{50}\text{of A with B}}{\mathrm{LD}_{50}\text{of A alone}}</math>