Clozapine Monitoring — MRCPsych Paper B MCQ

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EasySchizophrenia & PsychosisClozapine MonitoringMRCPsych Paper B

A 35-year-old woman has taken clozapine continuously for 2 years. Her white cell and neutrophil counts have remained in the monitoring service's green range, with no treatment interruptions. Her last haematological blood test was 5 weeks ago. Under current UK clozapine monitoring requirements, what is the routine minimum frequency of haematological monitoring at this stage?

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Correct answer: A — Every 4 weeks

The correct answer is A. Under UK clozapine monitoring requirements, patients with stable neutrophil counts may move to haematological monitoring at intervals of no more than 4 weeks after completing 1 year of treatment. This patient has received uninterrupted treatment for 2 years with results consistently in the green range, so her blood test is now overdue at 5 weeks. Weekly monitoring applies during the first 18 weeks, while 2-weekly monitoring applies between weeks 18 and 52. Routine monitoring every 3 or 6 months is not permitted under current UK requirements, although less frequent long-term monitoring has been discussed in the literature. Monitoring must continue throughout clozapine treatment and for at least 4 weeks after discontinuation.

Reference: Electronic Medicines Compendium. Clozapine Viatris 100 mg Tablets (Clozaril), Summary of Product Characteristics, UK Clozaril Official Recommendations and section 4.4, updated 13 March 2026. https://www.medicines.org.uk/emc/product/15498/smpc