therapeutic index

The therapeutic index (TI) is a measure that helps determine the safety of a drug by comparing the dose needed to produce a desired effect to the dose that could cause harm. Specifically, it is the ratio of the drug's toxic dose to its effective dose. A higher TI indicates a safer medication, as there is a larger gap between effective and harmful doses. Conversely, a low TI suggests a narrow margin of safety, requiring careful dosing to avoid toxicity. This concept helps healthcare providers balance the benefits and risks when prescribing medications.