Hypokalaemia (potassium deficiency)

Plasma potassium below 3.5 mmol/L. Most common causes: loop or thiazide diuretics, diarrhoea and vomiting, primary or secondary hyperaldosteronism, Cushing syndrome. Symptoms: muscle weakness, calf cramps, paraesthesias, arrhythmia. At <3.0 mmol/L the risk of ventricular arrhythmia rises, especially in patients on digoxin or QT-prolonging drugs. Treatment: address cause plus oral or IV potassium.

ICD-10 E87.61 drug

Also known as: Low potassium, Potassium deficiency, K+ < 3.5 mmol/L

Drugs used for this condition

BPotassium citrateFirst line · Potassium salt with systemic alkalinising effect, used for kidney stone prevention and hypokalaemiaPotassium citrate is used in hypokalaemia, especially when concurrent metabolic acidosis must be corrected – for example in distal renal tubular acidosis, Fanconi syndrome or severe diarrhoea. In thiazide- or loop-diuretic-induced hypokalaemia, potassium chloride is usually preferred because chloride is co-lost. Doses are titrated to plasma K+ and symptom severity, typically 20–40 mEq two to three times daily. Repeat K+ within 3–7 days, monitor renal function and concurrent hyperkalaemia-risk drugs – ACE-I, ARBs, spironolactone, eplerenone, trimethoprim. Guidelines: KDIGO 2020 and Spanish SEN 2022.

How to read tiers A–F

Evidence tiers belong to the drug-indication pair, not to the drug as a whole: the same substance can be A for one condition and F for another.

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit