Antipsychotics: acute dystonia: 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.

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Pharmacology · Antipsychotics: acute dystonia

Sample item

A 22-year-old man receives his second dose of haloperidol for acute psychosis. Within hours he develops sustained upward deviation of the eyes, a clenched jaw and neck twisting, and is frightened but conscious. Which treatment gives the fastest relief?

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

The answer and the reasoning

A. Intramuscular benztropine

Acute dystonia results from relative cholinergic overactivity when striatal D2 receptors are blocked. A parenteral anticholinergic such as benztropine, or a sedating antihistamine with antimuscarinic effects such as promethazine, relieves it within minutes. Propranolol is used for akathisia, not dystonia.

Option by option

  • A. Intramuscular benztropine (correct)

    Benztropine restores the cholinergic and dopaminergic balance and relieves the spasm.

  • B. Oral propranolol

    Propranolol treats akathisia and has no effect on acute dystonic spasm.

  • C. Intravenous phenytoin

    Phenytoin is an antiepileptic with no role in a drug-induced movement disorder.

  • D. Intravenous haloperidol to increase dopamine blockade

    More haloperidol would deepen the dopamine blockade and worsen the dystonia.

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.

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Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is A, Intramuscular benztropine. Acute dystonia results from relative cholinergic overactivity when striatal D2 receptors are blocked.

Why is "Oral propranolol" not the answer?

Propranolol treats akathisia and has no effect on acute dystonic spasm.

Why is "Intravenous phenytoin" not the answer?

Phenytoin is an antiepileptic with no role in a drug-induced movement disorder.

Why is "Intravenous haloperidol to increase dopamine blockade" not the answer?

More haloperidol would deepen the dopamine blockade and worsen the dystonia.

What concept does this question test?

It tests Antipsychotics: acute dystonia in Pharmacology. A parenteral anticholinergic such as benztropine, or a sedating antihistamine with antimuscarinic effects such as promethazine, relieves it within minutes. Propranolol is used for akathisia, not dystonia.

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 Antipsychotics: acute dystonia?

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.