1. What is Therapeutic Index?

The Therapeutic Index (TI) is a quantitative measurement of the relative safety of a drug. It compares the dose that produces a toxic effect (LD50) to the dose that produces a therapeutic effect (ED50). A higher TI indicates a safer drug.

2. How Does the Calculator Work?

The calculator uses the Therapeutic Index formula:

Where:

• \( LD_{50} \) — Lethal dose for 50% of the population (mg/kg)
• \( ED_{50} \) — Effective dose for 50% of the population (mg/kg)

Explanation: The TI represents the margin of safety for a drug. Drugs with a high TI are generally safer than those with a low TI.

3. Importance of Therapeutic Index

Details: The Therapeutic Index is crucial in pharmacology for assessing drug safety, determining appropriate dosing regimens, and comparing the safety profiles of different medications.

4. Using the Calculator

Tips: Enter both LD50 and ED50 values in mg/kg. Both values must be valid (greater than 0). The calculator will compute the Therapeutic Index.

5. Frequently Asked Questions (FAQ)

Q1: What is considered a good Therapeutic Index?
A: Generally, a TI greater than 10 is considered acceptable, while values above 100 indicate a very safe drug.

Q2: How is LD50 determined?
A: LD50 is typically determined through animal studies where increasing doses of a drug are administered to determine the lethal dose for 50% of the test population.

Q3: What are the limitations of Therapeutic Index?
A: TI doesn't account for individual variations, drug interactions, or different types of toxic effects. It's a general safety measure.

Q4: Can TI be used for all drugs?
A: TI is most useful for drugs with dose-dependent toxicity. It's less meaningful for drugs with idiosyncratic reactions or those with a narrow therapeutic window.

Q5: How does TI relate to therapeutic window?
A: Therapeutic window refers to the range between the minimum effective concentration and the minimum toxic concentration, while TI is a ratio of lethal to effective doses.