A drug with a higher therapeutic index is generally considered safer.

• A. A drug with a higher TI is generally considered safer
• B. A drug with a higher TI is riskier
• C. TI has no relation to safety
• D. TI measures potency

Answer: (A)

Therapeutic index reflects the safety margin of a drug. It compares the dose that produces toxicity or death to the dose that produces the desired therapeutic effect. A higher TI means there’s a larger gap between the effective dose and the toxic dose, so the drug can be used with less risk of toxicity for a given effect. This wider safety window is why it’s generally considered safer. Potency, on the other hand, is about how much drug is needed for an effect, not about how close toxicity is to therapy; a drug can be potent but still have a narrow safety margin if toxicity occurs near the effective dose. Conversely, a low TI indicates a narrow safety margin and requires careful dosing.