MCQ – 92400

Which of the following statements regarding the clinical therapeutic index is accurate?

A.	Therapeutic index is LD50/ED50
B.	Dose in which efficacy and toxicity can be balanced in an individual
C.	Indicative of therapeutic index in a population vs individual
D.	All of the Above

Show Answer

Correct Answer » A Explanation

The therapeutic index (TI) is a measure of a drug’s safety margin. It compares the dose that produces a therapeutic effect with the dose that produces toxicity or lethality.

It is calculated as:

Therapeutic Index (TI) = LD₅₀ / ED₅₀

Where:

• LD₅₀ (Median Lethal Dose) – dose that causes death in 50% of experimental animals

• ED₅₀ (Median Effective Dose) – dose that produces the desired therapeutic effect in 50% of the population

A higher therapeutic index indicates a safer drug, because there is a wider margin between the effective dose and the toxic dose.