Toxicology and antidotes: antivenom reaction: 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 and antidotes: antivenom reaction

Sample item

During infusion of polyvalent anti-snake venom, a bitten patient develops urticaria, wheeze and a blood pressure of 80/50 mmHg. What is the immediate step?

ASlow the infusion and add intravenous hydrocortisoneBContinue the infusion and give intravenous atropineCStop the infusion and give intravenous chlorpheniramine aloneDStop the infusion and give intramuscular adrenaline

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

The answer and the reasoning

D. Stop the infusion and give intramuscular adrenaline

Early anaphylactic reactions to antivenom are common. Adrenaline by the intramuscular route is the first-line treatment for anaphylaxis, with antihistamine and hydrocortisone as adjuncts. Once the patient is stable, antivenom can be restarted slowly if still indicated.

Option by option

A. Slow the infusion and add intravenous hydrocortisone
Hydrocortisone acts too slowly to treat shock and continuing the infusion adds antigen.
B. Continue the infusion and give intravenous atropine
Atropine treats bradycardia or cholinergic features and does nothing for anaphylaxis.
C. Stop the infusion and give intravenous chlorpheniramine alone
An antihistamine alone does not reverse hypotension or bronchospasm.
D. Stop the infusion and give intramuscular adrenaline (correct)
Correct. Intramuscular adrenaline is first-line for anaphylaxis, and the infusion is paused.

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.

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Stop the infusion and give intramuscular adrenaline. Early anaphylactic reactions to antivenom are common.

Why is "Slow the infusion and add intravenous hydrocortisone" not the answer?

Hydrocortisone acts too slowly to treat shock and continuing the infusion adds antigen.

Why is "Continue the infusion and give intravenous atropine" not the answer?

Atropine treats bradycardia or cholinergic features and does nothing for anaphylaxis.

Why is "Stop the infusion and give intravenous chlorpheniramine alone" not the answer?

An antihistamine alone does not reverse hypotension or bronchospasm.

What concept does this question test?

It tests Toxicology and antidotes: antivenom reaction in Pharmacology. Adrenaline by the intramuscular route is the first-line treatment for anaphylaxis, with antihistamine and hydrocortisone as adjuncts. Once the patient is stable, antivenom can be restarted slowly if still indicated.

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 and antidotes: antivenom reaction?

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.