Calculate therapeutic index from TD50 or LD50 and ED50, or solve for a missing dose value with mg, g, µg, and kg unit options and view interpretation.
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Therapeutic Index Formula
The following formula is used to calculate the Therapeutic Index.
Variables:
- TI is the Therapeutic Index
- TD50 is the median toxic dose
- ED50 is the median effective dose
To calculate the Therapeutic Index, divide the median toxic dose by the median effective dose. The Therapeutic Index is a measure of the safety of a drug, with higher values indicating a safer drug.
What is a Therapeutic Index?
A Therapeutic Index (TI) is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity. It is used to assess the safety margin of drugs, with a higher TI indicating a safer drug. The closer the TI is to 1, the more likely the drug is to cause toxicity. Therefore, drugs with a high TI are preferred for treatment as they have a wider margin of safety.
How to Calculate Therapeutic Index?
The following steps outline how to calculate the Therapeutic Index (TI) using the formula TI = TD50 / ED50.
- First, determine the median toxic dose (TD50).
- Next, determine the median effective dose (ED50).
- Next, gather the formula from above = TI = TD50 / ED50.
- Finally, calculate the Therapeutic Index (TI).
- After inserting the values for TD50 and ED50 and calculating the result, check your answer with the calculator above.
Example Problem:
Use the following variables as an example problem to test your knowledge:
TD50 (median toxic dose) = 50
ED50 (median effective dose) = 10
