Local anaesthetics: 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.

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Anaesthesia · Local anaesthetics

Sample item

A patient reports urticaria and bronchospasm after a dental local anaesthetic injection. Which statement about local anaesthetic allergy is correct?

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

The answer and the reasoning

D. Ester-type agents are more allergenic because they are metabolised to para-aminobenzoic acid

Ester local anaesthetics such as procaine and benzocaine are hydrolysed by plasma cholinesterase to para-aminobenzoic acid, a recognised allergen. True allergy to amides such as lignocaine is rare, and reactions are often caused by preservatives like methylparaben or by adrenaline. Cross-reactivity within the ester group is common.

Option by option

  • A. Both classes contain the same allergenic metabolite

    The two classes differ in metabolites, so this is false.

  • B. Allergy is unrelated to the chemical class and preservative

    Chemical class matters, and preservatives are only a part of the picture.

  • C. Amide-type agents are more allergenic because they are metabolised to para-aminobenzoic acid

    Amides are metabolised in the liver and do not produce PABA.

  • D. Ester-type agents are more allergenic because they are metabolised to para-aminobenzoic acid (correct)

    Correct. Ester metabolism to PABA explains their higher allergy potential.

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 D, Ester-type agents are more allergenic because they are metabolised to para-aminobenzoic acid. Ester local anaesthetics such as procaine and benzocaine are hydrolysed by plasma cholinesterase to para-aminobenzoic acid, a recognised allergen.

Why is "Both classes contain the same allergenic metabolite" not the answer?

The two classes differ in metabolites, so this is false.

Why is "Allergy is unrelated to the chemical class and preservative" not the answer?

Chemical class matters, and preservatives are only a part of the picture.

Why is "Amide-type agents are more allergenic because they are metabolised to…" not the answer?

Amides are metabolised in the liver and do not produce PABA.

What concept does this question test?

It tests Local anaesthetics in Anaesthesia. True allergy to amides such as lignocaine is rare, and reactions are often caused by preservatives like methylparaben or by adrenaline. Cross-reactivity within the ester group is common.

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 Local anaesthetics?

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.