Toxicology: local anaesthetic systemic toxicity: 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 · Toxicology: local anaesthetic systemic toxicity

Sample item

During a brachial plexus block with bupivacaine, a patient develops perioral numbness and tinnitus, followed by a generalised seizure and ventricular arrhythmia. Which treatment is specific?

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

The answer and the reasoning

C. Intravenous 20% lipid emulsion

Bupivacaine strongly blocks cardiac sodium channels and dissociates slowly, so toxicity can cause refractory arrhythmia and arrest. Lipid emulsion acts as a lipid sink, drawing lipophilic anaesthetic out of the tissues, and may improve myocardial function. Seizures are treated with benzodiazepines, and the airway and ventilation are secured.

Option by option

  • A. Atropine

    Atropine does not treat ventricular arrhythmia due to sodium channel block.

  • B. Intravenous phenytoin

    Phenytoin is a sodium channel blocker and could worsen cardiac depression.

  • C. Intravenous 20% lipid emulsion (correct)

    Lipid emulsion sequesters bupivacaine and is the specific rescue therapy.

  • D. Intravenous calcium chloride

    Calcium chloride does not reverse sodium channel blockade by local anaesthetics.

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 C, Intravenous 20% lipid emulsion. Bupivacaine strongly blocks cardiac sodium channels and dissociates slowly, so toxicity can cause refractory arrhythmia and arrest.

Why is "Atropine" not the answer?

Atropine does not treat ventricular arrhythmia due to sodium channel block.

Why is "Intravenous phenytoin" not the answer?

Phenytoin is a sodium channel blocker and could worsen cardiac depression.

Why is "Intravenous calcium chloride" not the answer?

Calcium chloride does not reverse sodium channel blockade by local anaesthetics.

What concept does this question test?

It tests Toxicology: local anaesthetic systemic toxicity in Pharmacology. Lipid emulsion acts as a lipid sink, drawing lipophilic anaesthetic out of the tissues, and may improve myocardial function. Seizures are treated with benzodiazepines, and the airway and ventilation are secured.

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 Toxicology: local anaesthetic systemic toxicity?

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.