Potassium chloride
Addex-Kaliumklorid · Kaliumklorid B. Braun · Kaleorid
Potassium deficiency is corrected slowly because extracellular potassium is only two per cent of the body's total potassium store — the plasma value indicates the starting point, not the magnitude of the deficit. Rate, not daily dose, is what determines safety: peripherally 10 mmol per hour, in a central vein up to 20 mmol per hour, and at most 40 mmol per hour in life-threatening hypokalaemia under continuous ECG monitoring. Hypokalaemia that refuses to rise despite adequate replacement is almost always caused by concurrent hypomagnesaemia, and magnesium must then be given first.
Concentrated potassium chloride must never be given as a bolus or undiluted — it causes asystole within seconds and is one of the classic fatal drug mix-ups. The concentrate must always be added to an infusion bag, inverted and labelled before connection, and ready-mixed solutions should be used when available.
Dosing in adults
| Indication | Regimen | Comment |
|---|---|---|
| Mild hypokalaemia (plasma potassium 3,0–3,5 mmol/l) with functioning gastrointestinal tract | orally 40–80 mmol per day divided into 2–3 doses | oral slow-release tablets are first choice when the patient can swallow |
| Moderate hypokalaemia (plasma potassium 2,5–3,0 mmol/l) | 40 mmol potassium chloride in 1 000 ml sodium chloride 9 mg/ml iv over 4–6 hours, repeated after review | peripherally at most 10 mmol per hour and concentration at most 40 mmol/l |
| Severe hypokalaemia (plasma potassium < 2,5 mmol/l) or arrhythmia | 10–20 mmol per hour in a central vein, up to 40 mmol per hour in life-threatening hypokalaemia | requires a central venous catheter, continuous ECG monitoring, and review every 1–2 hours |
| Deficit estimation | a fall of 0,3 mmol/l below 3,5 corresponds roughly to 100 mmol total deficit; plasma potassium 2,5 mmol/l often implies 300–400 mmol | rough estimate — guide on repeated measurements, not on the formula |
| Therapy-resistant hypokalaemia | magnesium sulfate 20–40 mmol iv per day in parallel with potassium replacement | without magnesium correction the kidney continues to lose potassium |
At eGFR below 30 ml/min, halve the replacement rate and check plasma potassium at least every 4 hours; in oligo- or anuria potassium should not generally be given without first investigating the cause. Potassium-sparing diuretics, ACE inhibitors, ARBs, and MRAs should be stopped or dose-reduced before replacement begins.
No dose adjustment. In liver cirrhosis with secondary hyperaldosteronism and diuretic treatment, potassium losses are often large and requirements exceed estimates.
0,5–1 mmol/kg iv over 1–2 hours, at most 0,5 mmol/kg per hour and maximum adult dose. Concentration peripherally at most 40 mmol/l; higher concentration requires central access and ECG monitoring.
Do not chase the plasma value with a faster infusion when potassium is not rising — the most common cause is untreated hypomagnesaemia, and the solution is magnesium, not a higher rate. Also avoid iv replacement when the patient can swallow: oral administration is equally effective, considerably safer, and avoids both vein irritation and the risk of overcorrection.
Pharmacokinetics
- ONSET
- minutes iv, 1–2 hours orally
- DISTRIBUTION
- 98 % intracellular — the plasma value reflects the store poorly
- CONTENT
- Addex-Kaliumklorid 2 mmol/ml, 20 ml ampoule = 40 mmol
- MAX RATE PERIPHERAL
- 10 mmol/h, concentration at most 40 mmol/l
- MAX RATE CENTRAL
- 20 mmol/h, exceptionally 40 mmol/h with ECG monitoring
- EXCRETION
- Renal, aldosterone-dependent tubular secretion
- NORMAL VALUE
- 3,5–4,4 mmol/l in plasma
- CONVERSION
- 1 g potassium chloride ≈ 13,4 mmol potassium