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 needed to produce the desired therapeutic response (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 formula calculates the ratio between the toxic dose and the effective dose, providing a measure of drug safety.

3. Importance of Therapeutic Index

Details: Therapeutic Index is crucial in pharmacology for evaluating drug safety. Drugs with a high TI have a wide margin of safety, while those with a low TI require careful dosing and monitoring.

4. Using the Calculator

Tips: Enter both LD50 and ED50 values in mg/kg. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is considered a good Therapeutic Index?
A: Generally, a TI greater than 10 is considered acceptable, with higher values indicating greater safety.

Q2: Are there limitations to using Therapeutic Index?
A: Yes, TI doesn't account for individual variations, drug interactions, or different types of toxicity. It's a general safety indicator.

Q3: How is LD50 determined for humans?
A: Human LD50 values are typically extrapolated from animal studies and historical data, as direct testing in humans is unethical.

Q4: Can Therapeutic Index vary between populations?
A: Yes, factors like age, genetics, and health status can affect both LD50 and ED50 values, potentially altering the TI.

Q5: Is Therapeutic Index the only measure of drug safety?
A: No, other factors like side effect profile, therapeutic window, and margin of safety are also important considerations.