Potassium chloride

How it works

It replaces the potassium ion, the principal intracellular cation essential for nerve conduction, muscle contraction and cardiac rhythm, correcting a deficit and its associated effects.

Prescribing in practice

• Intravenous potassium chloride must always be diluted and infused slowly with cardiac monitoring, as bolus or concentrated administration can cause fatal cardiac arrest; this is a recognised never-event hazard.
• Use cautiously in renal impairment and with potassium-sparing diuretics, RAS inhibitors or aldosterone antagonists because of the risk of hyperkalaemia.
• Oral modified-release tablets should be swallowed whole with plenty of fluid, ideally sitting or standing, to limit gastrointestinal ulceration.

Monitoring

Monitor serum potassium and renal function, with continuous ECG monitoring during intravenous replacement.

Counselling the patient

• Swallow the tablets whole with a full glass of water and do not crush or chew them.
• Report muscle weakness, palpitations or tingling, which may signal too much potassium.

Evidence & guidelines

Its role in correcting potassium deficits is well established, with current prescribing references and the SPC emphasising the dangers of inappropriate intravenous administration.