Antipsychotic Side Effects — MRCPsych Paper B MCQ

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ModerateSchizophrenia & PsychosisAntipsychotic Side EffectsMRCPsych Paper B

A 40-year-old woman with schizophrenia has experienced repeated relapses because of covert non-adherence. She developed marked weight gain and metabolic syndrome while taking olanzapine. She has now been clinically stable for 8 weeks on oral aripiprazole, which she has tolerated without significant akathisia or impulse-control symptoms, and requests long-acting injectable treatment. Which LAI is the most appropriate?

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Correct answer: B — Aripiprazole monohydrate LAI

B, aripiprazole monohydrate LAI, is the most appropriate choice. She is already clinically stable on and tolerates oral aripiprazole, satisfying the UK licensing requirement for oral stabilisation before the LAI is started. Aripiprazole also has comparatively low metabolic liability, which is important given her olanzapine-associated weight gain and metabolic syndrome. Olanzapine pamoate would retain olanzapine's high metabolic risk. Paliperidone has greater weight-gain and prolactin liability than aripiprazole. Flupentixol and zuclopenthixol can be relatively metabolically sparing, but have greater extrapyramidal and hyperprolactinaemic liability and would require changing from an already effective, tolerated drug. Metabolic monitoring remains necessary because aripiprazole can still cause clinically significant weight gain in some patients.

Reference: Electronic Medicines Compendium, Aripiprazole Otsuka 400 mg prolonged-release suspension for injection, SmPC sections 4.1, 4.2 and 4.8, updated 2024. https://www.medicines.org.uk/emc/product/7965/smpc