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Hyperkalaemia risk — GPhC CRA MCQ

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HardCardiovascular TherapeuticsHyperkalaemia riskGPhC CRA

A 80-year-old woman taking spironolactone 25 mg daily for heart failure is prescribed potassium citrate mixture for urinary symptoms. Her latest potassium is 5.3 mmol/L and eGFR is 39 mL/min/1.73 m². What is the most important interaction to flag?

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Correct answer: C — Contact the prescriber because potassium salts may worsen hyperkalaemia

Spironolactone increases potassium and the patient already has hyperkalaemia with renal impairment. Potassium citrate could worsen hyperkalaemia and provoke arrhythmia. The prescriber should review the urinary indication and safer alternatives. Dietary or fluid advice does not mitigate the medicine-related risk.

Reference: BNF