A larger TI value is associated with which of the following?

A larger TI value is associated with which of the following?

• A. Higher chance of toxicity at therapeutic doses
• B. Higher drug safety
• C. Narrower therapeutic window
• D. Lower drug safety

Answer: (B)

Therapeutic index shows the safety margin between the dose that provides a therapeutic effect and the dose that causes toxicity. A larger value means the toxic dose is much higher than the effective dose, giving a wide safety margin. That translates to higher drug safety at therapeutic doses because you’re farther from the point where toxicity occurs. For example, if the effective dose is 10 mg and the toxic dose is 100 mg, the index is large, indicating a comfortable safety cushion. If the toxic dose were closer to the effective dose, the margin would be small and safety would be reduced. So a larger therapeutic index corresponds to higher drug safety.

Therapeutic index shows the safety margin between the dose that provides a therapeutic effect and the dose that causes toxicity. A larger value means the toxic dose is much higher than the effective dose, giving a wide safety margin. That translates to higher drug safety at therapeutic doses because you’re farther from the point where toxicity occurs. For example, if the effective dose is 10 mg and the toxic dose is 100 mg, the index is large, indicating a comfortable safety cushion. If the toxic dose were closer to the effective dose, the margin would be small and safety would be reduced. So a larger therapeutic index corresponds to higher drug safety.