Anaesthetic pharmacology: curriculum recognition: practice question

A Anaesthesia 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

Anaesthesia · Anaesthetic pharmacology: curriculum recognition

Sample item

Bupivacaine blocks nerves at much lower concentrations than lignocaine. Which physicochemical property chiefly explains its greater potency?

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

The answer and the reasoning

A. Higher lipid solubility

Potency of local anaesthetics tracks lipid solubility, because a lipid-soluble molecule crosses the nerve membrane more easily and reaches its site of action in greater amounts. A lower pKa speeds onset, and protein binding prolongs duration.

Option by option

  • A. Higher lipid solubility (correct)

    Correct. Greater lipid solubility means greater potency.

  • B. Lower molecular weight

    Bupivacaine is a larger molecule than lignocaine.

  • C. Higher water solubility

    Higher water solubility would reduce membrane penetration and lower potency.

  • D. Lower pKa

    A lower pKa leaves more drug unionised and gives faster onset, not greater potency.

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 Anaesthesia questions

Questions about this Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is A, Higher lipid solubility. Potency of local anaesthetics tracks lipid solubility, because a lipid-soluble molecule crosses the nerve membrane more easily and reaches its site of action in greater amounts.

Why is "Lower molecular weight" not the answer?

Bupivacaine is a larger molecule than lignocaine.

Why is "Higher water solubility" not the answer?

Higher water solubility would reduce membrane penetration and lower potency.

Why is "Lower pKa" not the answer?

A lower pKa leaves more drug unionised and gives faster onset, not greater potency.

What concept does this question test?

It tests Anaesthetic pharmacology: curriculum recognition in Anaesthesia. A lower pKa speeds onset, and protein binding prolongs duration.

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 Anaesthetic pharmacology: curriculum recognition?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.