Hypokalemia & Hyperkalemia
ABCs
- check vitals, assess for arrhythmia symptoms, weakness, hemodynamic instability
- review meds → ACEi, ARBs, diuretics, NSAIDs
- repeat sample if hemolyzed
- ECG
- hypokalemia: U waves, ST depression
- hyperkalemia: peaked T waves, wide QRS
hypokalemia
- features: palpitations, muscle cramps or weakness, ileus, nausea
ECGT-wave flattening + U waves
replacement by band
| 3.0–3.5mild · mmol/L | oral KCl (Slow-K) 1–2 tabs TDS · repeat RFT next day if on NGT → Slow-K can’t be crushed, use KCl syrup 6.6% instead |
| 2.5–3.0moderate · mmol/L | IV KCl 20 mmol in 200 mL NS over 2 h |
| < 2.5severe · mmol/L | IV KCl 40 mmol in 400 mL NS over 4 h + cardiac monitoring |
correct magnesium first or alongside
- low Mg drives ongoing K loss — replacing K alone won’t hold
- recheck K after replacement
- add oral if tolerated
- stop replacement once K > 4.5 mmol/L
hyperkalemia
- features: palpitations, muscle weakness, hypotension
ECGpeaked T waves, prolonged PR/QRS, sine wave (severe)
act by band
| ≥ 5.5or ECG changes |
stabilize + shift
|
| > 6.0severe · mmol/L | all of the above + start potassium binder · escalate early |
potassium binders
| drug | onset | use |
|---|---|---|
| Lokelma | ~ 1 h | acute/subacute · preferred on-call option |
| Veltassa | 4–7 h | chronic · not for emergencies |
- cardiac monitoring
- repeat K after treatment
- stop offending drugs
available potassium (MOH)
| route | drug | content |
|---|---|---|
| IV | KCl 15% | 10 mL = 20 mmol K |
| IV | potassium phosphate | 15 mL ≈ 66 mEq K |
| oral | Slow-K | 600 mg ≈ 8–9 mmol K |
| oral | KCl syrup 6.6% | ~ 1.3 mmol per 1.5 mL |
| oral | potassium citrate syrup | ~ 6.6 mEq per 5 mL |
| binder | Calcium Resonium | oral or rectal |
| binder | Resonium A | oral or rectal |
| binder | Lokelma | oral |
| binder | Veltassa | oral |
| adjunct | lactulose | oral or rectal |
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Last reviewed · May 2026