Epilepsy in Dementia — MRCPsych Paper B MCQ

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HardOld Age PsychiatryEpilepsy in DementiaMRCPsych Paper B

A 68-year-old woman with moderate Alzheimer's disease, treated with rivastigmine, develops recurrent focal impaired-awareness seizures. Neurological assessment identifies no drug-specific contraindication, and the candidate antiseizure medicines are considered otherwise clinically suitable. When preservation of language and executive function is the overriding concern, which medicine is least suitable because it has the strongest recognised propensity to cause cognitive adverse effects?

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Correct answer: A — Topiramate

Topiramate is the single best answer. Its UK SmPC specifically warns of cognitive impairment that may require dose reduction or discontinuation and lists bradyphrenia, expressive language disorder, impaired attention and memory, cognitive disorder, and psychomotor slowing. These effects are particularly undesirable in someone with established Alzheimer's disease, although dementia is not a formal contraindication. Lamotrigine has a comparatively favourable cognitive profile. Levetiracetam is also commonly used for focal epilepsy, although irritability and other behavioural adverse effects may limit it. Lacosamide is more characteristically associated with dizziness, diplopia and coordination problems. Sodium valproate can cause sedation, tremor and other important toxicity, but it is less specifically associated than topiramate with the characteristic language and executive-function impairment tested here.

Reference: Electronic Medicines Compendium. Topiramate 100 mg film-coated tablets, Summary of Product Characteristics, sections 4.4 and 4.8. Updated 10 March 2025. https://www.medicines.org.uk/emc/product/100615/smpc