CNS drugs and antiepileptics: thiamine before glucose: 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 · CNS drugs and antiepileptics: thiamine before glucose

Sample item

A 48-year-old man with chronic alcohol use is brought in with confusion, an ataxic gait and horizontal nystagmus. Capillary glucose is 52 mg/dL and an intravenous dextrose infusion is planned. Which drug must be given with or before the glucose?

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

The answer and the reasoning

D. Intravenous thiamine

The picture is Wernicke encephalopathy. A glucose load in a thiamine-deficient patient consumes the remaining thiamine and can precipitate or worsen the encephalopathy, so parenteral thiamine is given first or together with dextrose.

Option by option

  • A. Intravenous folic acid

    Folic acid corrects megaloblastic anaemia and does not prevent Wernicke encephalopathy.

  • B. Intravenous flumazenil

    Flumazenil reverses benzodiazepine sedation, and nothing here suggests benzodiazepine toxicity.

  • C. Intravenous naloxone

    Naloxone reverses opioid effect and would not treat the ocular and gait signs of thiamine deficiency.

  • D. Intravenous thiamine (correct)

    Correct. Thiamine prevents glucose from precipitating or worsening Wernicke encephalopathy.

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 D, Intravenous thiamine. The picture is Wernicke encephalopathy.

Why is "Intravenous folic acid" not the answer?

Folic acid corrects megaloblastic anaemia and does not prevent Wernicke encephalopathy.

Why is "Intravenous flumazenil" not the answer?

Flumazenil reverses benzodiazepine sedation, and nothing here suggests benzodiazepine toxicity.

Why is "Intravenous naloxone" not the answer?

Naloxone reverses opioid effect and would not treat the ocular and gait signs of thiamine deficiency.

What concept does this question test?

It tests CNS drugs and antiepileptics: thiamine before glucose in Pharmacology. A glucose load in a thiamine-deficient patient consumes the remaining thiamine and can precipitate or worsen the encephalopathy, so parenteral thiamine is given first or together with dextrose.

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 CNS drugs and antiepileptics: thiamine before glucose?

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.