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Normal Potassium — FRCA Primary MCQ

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HardPhysiology - Endocrine & MetabolicNormal PotassiumFRCA Primary

A monitored patient has weakness, ventricular ectopy and potassium 2.3 mmol L−1 despite oral replacement. Urine output is adequate. Which intravenous replacement plan is within the current UK SmPC approach for severe symptomatic deficiency?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — Diluted potassium at 20 mmol h−1 under ECG monitoring

The best answer is “Diluted potassium at 20 mmol h−1 under ECG monitoring”. For severe symptomatic potassium deficiency below 2.5 mmol L−1, the cited UK SmPC permits diluted, pump-controlled replacement up to 20 mmol h−1 with appropriate monitoring. Faster 40 mmol h−1 treatment is an exceptional option below 2.0 mmol L−1 with continuous ECG. Potassium concentrate must never be bolused, and insulin would worsen the deficit by shifting potassium intracellularly.

Reference: Sterile potassium chloride concentrate 15% w/v, UK SmPC: https://www.medicines.org.uk/emc/product/15218/smpc; Royal College of Anaesthetists, Primary FRCA syllabus v2.2: https://www.rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf