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Abiraterone Mineralocorticoid Syndrome — RACP Adult Medicine MCQ

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HardMedical OncologyAbiraterone Mineralocorticoid SyndromeRACP Adult Medicine

A 68-year-old man on abiraterone for metastatic prostate cancer develops lower limb oedema and hypokalaemia (K+ 2.8 mmol/L). BP is 170/100 mmHg. His prednisolone dose has inadvertently been missed for 2 weeks. What is the cause of his symptoms?

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Correct answer: D — Primary aldosteronism

Abiraterone inhibits CYP17A1, blocking both androgen and cortisol synthesis. When prednisolone is NOT co-administered, ACTH rises unopposed, driving overproduction of mineralocorticoid precursors (deoxycorticosterone, corticosterone) that cause hypertension, hypokalaemia, and fluid retention. Prednisolone co-administration (5 mg BD) is MANDATORY with abiraterone to suppress ACTH and prevent this mineralocorticoid syndrome. Resuming prednisolone resolves the symptoms.

Reference: AMH – 2025 – Abiraterone; eTG – 2025 – Oncology