Psychotic disorders: restarting clozapine after missed doses: practice question

A Psychiatry 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

Psychiatry · Psychotic disorders: restarting clozapine after missed doses

Sample item

A man stable on clozapine 400 mg daily had to stop it when he was admitted to a general hospital, and has now missed all doses for four days. What is the safest way to resume?

ARestart at a low dose and re-titrate graduallyBChange permanently to a depot antipsychoticCResume the full previous dose at onceDGive a double dose on day one to catch up

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

The answer and the reasoning

A. Restart at a low dose and re-titrate gradually

Tolerance to the sedative, hypotensive and cardiac effects of clozapine is lost within a couple of days. After an interruption of more than about two days it should be restarted at the low initial dose and titrated up again, because full-dose resumption can cause collapse, syncope and cardiac events.

Option by option

A. Restart at a low dose and re-titrate gradually (correct)
Correct. Tolerance is lost after a gap of more than about two days, so re-titration from a low dose is advised.
B. Change permanently to a depot antipsychotic
A depot switch is not a safety measure and clozapine has no depot form.
C. Resume the full previous dose at once
Resuming the full dose risks profound hypotension, syncope and bradycardia.
D. Give a double dose on day one to catch up
A double dose would worsen these risks further and has no pharmacological basis.

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 Psychiatry question

What is the answer to this Psychiatry question?

The best answer is A, Restart at a low dose and re-titrate gradually. Tolerance to the sedative, hypotensive and cardiac effects of clozapine is lost within a couple of days.

Why is "Change permanently to a depot antipsychotic" not the answer?

A depot switch is not a safety measure and clozapine has no depot form.

Why is "Resume the full previous dose at once" not the answer?

Resuming the full dose risks profound hypotension, syncope and bradycardia.

Why is "Give a double dose on day one to catch up" not the answer?

A double dose would worsen these risks further and has no pharmacological basis.

What concept does this question test?

It tests Psychotic disorders: restarting clozapine after missed doses in Psychiatry. After an interruption of more than about two days it should be restarted at the low initial dose and titrated up again, because full-dose resumption can cause collapse, syncope and cardiac events.

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 Psychotic disorders: restarting clozapine after missed doses?

Learn each diagnosis by its core features and its first-line treatment. Then use the flashcards and the other Psychiatry 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.