Clozapine Monitoring — MRCPsych Paper B MCQ

Instant feedback + full explanation. One question, done properly.

ModerateSchizophrenia & PsychosisClozapine MonitoringMRCPsych Paper B

A 50-year-old woman with chronic schizophrenia takes clozapine and is monitored using standard thresholds; she does not have benign ethnic neutropenia. Routine monitoring shows an absolute neutrophil count of 1.2 × 10^9/L, compared with previous results consistently above 2.0 × 10^9/L. She is otherwise well. What is the immediate action?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Discontinue clozapine and arrange daily FBCs

Explanation lettering: B = shown as A · D = shown as B · A = shown as C · C = shown as D

Under standard UK clozapine monitoring thresholds, an absolute neutrophil count below 1.5 × 10^9/L is a red result. Clozapine must therefore be discontinued after the first abnormal result, even if the patient is asymptomatic. FBCs should be obtained daily until haematological recovery, with active monitoring for fever, sore throat or other evidence of infection and notification of the monitoring service. Continuing clozapine with twice-weekly testing (E) is appropriate for an amber ANC of 1.5–2.0 × 10^9/L under standard thresholds, not an ANC of 1.2. Weekly or fortnightly monitoring (A and D) is unsafe, and dose reduction (C) is not an accepted response to a red haematological result. Under the licensed UK protocol, patients discontinued for this reason must not be re-exposed.

Reference: Viatris Products Limited. Clozapine Viatris 100 mg Tablets Summary of Product Characteristics, section 4.4, Low WBC count/ANC and Table 1. Revised February 2026. https://www.medicines.org.uk/emc/product/15498/smpc