Enzalutamide Seizures — RACP Adult Medicine MCQ

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ModerateMedical OncologyEnzalutamide SeizuresRACP Adult Medicine

A 55-year-old man with metastatic castration-resistant prostate cancer on enzalutamide develops fatigue and seizures. CT brain shows no metastases. What is the most likely cause of the seizures?

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Correct answer: E — Enzalutamide-induced seizure (crosses BBB and lowers seizure threshold)

Enzalutamide crosses the blood-brain barrier and is associated with seizures in approximately 0.9% of patients (higher in those with predisposing factors). It lowers the seizure threshold through GABA-A receptor inhibition. Enzalutamide is contraindicated in patients with a history of seizures or conditions predisposing to seizures. If seizures occur, enzalutamide should be permanently discontinued. Apalutamide and darolutamide have lower seizure risk and are alternatives.

Reference: AMH – 2025 – Enzalutamide; Cancer Council Australia – 2023 – Prostate Cancer Guidelines