General pharmacology and pharmacokinetics: certain safety factor: practice question

A Pharmacology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Pharmacology · General pharmacology and pharmacokinetics: certain safety factor

Sample item

A pharmacologist wants a safety index that compares the dose lethal to the most sensitive 1 percent with the dose effective in 99 percent, because the dose-response curves for effect and lethality overlap. Which index is this?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Certain safety factor

The certain safety factor is LD1 divided by ED99 and is more conservative than the therapeutic index, which uses LD50 and ED50. It guards against overlap of the curves at the extremes.

Option by option

  • A. Intrinsic activity

    Intrinsic activity describes the maximal response relative to a full agonist.

  • B. Certain safety factor (correct)

    Correct. It uses LD1 and ED99 to account for curve overlap.

  • C. Therapeutic index based on median doses

    The therapeutic index uses median doses, which hide overlap at the tails of the curves.

  • D. Potency ratio

    Potency compares doses needed for equal effect between drugs and says nothing about safety.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Pharmacology questions

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is B, Certain safety factor. The certain safety factor is LD1 divided by ED99 and is more conservative than the therapeutic index, which uses LD50 and ED50.

Why is "Intrinsic activity" not the answer?

Intrinsic activity describes the maximal response relative to a full agonist.

Why is "Therapeutic index based on median doses" not the answer?

The therapeutic index uses median doses, which hide overlap at the tails of the curves.

Why is "Potency ratio" not the answer?

Potency compares doses needed for equal effect between drugs and says nothing about safety.

What concept does this question test?

It tests General pharmacology and pharmacokinetics: certain safety factor in Pharmacology. It guards against overlap of the curves at the extremes.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study General pharmacology and pharmacokinetics: certain safety factor?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.