Answer :
A drug with a high therapeutic index has a wide margin of safety, meaning there is a substantial difference between its effective dose and its toxic dose. This allows for a safer administration of the drug with less risk of toxicity. Hence the correct answer is option D
The Therapeutic Index (TI) is a crucial concept in pharmacology that provides information about the relative safety of a drug. It is represented as the ratio between the toxic dose (TD50) that can cause harm to 50% of the population and the effective dose (ED50) that provides the desired therapeutic response in 50% of the population. A drug with a high therapeutic index signifies that there is a wide margin of safety, meaning there is a substantial difference between the dose needed for the desired effect and the dose that could cause toxicity.
Therefore, the correct answer to the student's question is that a drug with a high therapeutic index "Has a wide range between when its beneficial effects and its toxic effects occur". This indicates that the drug can be administered with less risk of adverse effects, as higher doses relative to the effective dose are needed before reaching a potentially harmful level.
For example, if the TD50 of a drug is 200 mg and its ED50 is 20 mg, the TI would be 10, showing that it has a favorable safety profile since the therapeutic dose is much lower than the dangerous dose. Hence the correct answer is option D
