TI larger value indicates what about safety margins?

TI larger value indicates what about safety margins?

• A. TI larger value indicates a greater safety margin between therapeutic and toxic doses.
• B. TI has no relation to safety margins.
• C. TI measures time to toxicity.
• D. TI is equal to LD50.

Answer: (A)

The key idea here is the therapeutic index, a ratio that expresses the safety margin of a drug. The therapeutic index compares doses that cause toxicity to doses that produce the desired therapeutic effect (often TD50/ED50). A larger number means you can give a higher dose before toxicity appears, so there’s a bigger gap between the effective dose and the toxic dose. That wider gap is what we mean by a greater safety margin. For example, if the effective dose is 10 units and the toxic dose occurs at 100 units, the TI is 10, indicating a fairly wide safety buffer. If another drug has an effective dose of 10 units but a toxic dose at 15 units, its TI is 1.5, showing a narrow safety margin and higher risk with dosing errors. The other statements don’t fit because the therapeutic index is about dose-based safety margins, not time to toxicity, and it isn’t simply equal to LD50 in all definitions (it's a ratio that involves doses, not a fixed single value).

The key idea here is the therapeutic index, a ratio that expresses the safety margin of a drug. The therapeutic index compares doses that cause toxicity to doses that produce the desired therapeutic effect (often TD50/ED50). A larger number means you can give a higher dose before toxicity appears, so there’s a bigger gap between the effective dose and the toxic dose. That wider gap is what we mean by a greater safety margin.

For example, if the effective dose is 10 units and the toxic dose occurs at 100 units, the TI is 10, indicating a fairly wide safety buffer. If another drug has an effective dose of 10 units but a toxic dose at 15 units, its TI is 1.5, showing a narrow safety margin and higher risk with dosing errors.

The other statements don’t fit because the therapeutic index is about dose-based safety margins, not time to toxicity, and it isn’t simply equal to LD50 in all definitions (it's a ratio that involves doses, not a fixed single value).