A large TI indicates higher safety.

• A. True
• B. False
• C. Not necessarily related
• D. Depends on route

Answer: (A)

The main idea here is the therapeutic index, which measures the safety margin of a drug by comparing the dose that produces toxicity to the dose that produces therapeutic effect. A larger TI means there is a bigger gap between the effective dose and the toxic dose, so the drug has a wider safety margin. For example, if the therapeutic dose is around 5 mg and toxicity occurs at 500 mg, the TI is 100, indicating high safety margin. It’s worth noting that TI is defined for a specific route of administration, and real-world safety also depends on patient factors, drug interactions, and how the drug is used, so a high TI isn’t a guarantee of safety in all situations.