Hypokalemia & Hyperkalemia

at the bedside

check vitals → 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

escalate now if

hypokalemia

hyperkalemia

repeat K⁺ with Mg⁺⁺ and full RFT
number looks wrong, or patient unwell → VBG or i-STAT Chem 8 now to confirm: the formal lab takes hours
ECG now → don’t wait for the repeat (patterns: at the bedside)

hypokalemia, by level

K⁺ 3.0–3.5 → Slow-K 1–2 tabs PO TDS, RFT next day; NGT → KCl syrup 6.6% 10–20 mL TDS (≈ 9–18 mmol)
K⁺ 2.5–3.0 → KCl 20 mmol in 200 mL NaCl 0.9% IV over 2 h, repeat by level
K⁺ < 2.5 or arrhythmia → KCl 40 mmol in 400 mL NaCl 0.9% IV over 4 h, monitored
these mixes are 100 mmol/L at 10 mmol/h: large vein + monitor, or central line; unmonitored peripheral → ≤ 40 mmol/L (20 mmol in 500 mL) and ≤ 10 mmol/h
- route, line and monitoring for 100 mmol/L → confirm your hospital’s IV potassium policy before giving it peripherally (premixed bag and KCl added on the ward are not the same)
MgSO₄ 2 g in 100 mL NaCl 0.9% IV over 1 h alongside: low Mg keeps K⁺ falling
recheck K⁺ after each bag; stop at K⁺ > 4.5; oral once tolerated

hyperkalemia, by band · UKKA 2023

K⁺ 5.5–5.9, no ECG changes: treat the cause, not the number

stop or hold K⁺-raising drugs: ACEi / ARB / MRA, K⁺ supplements, trimethoprim, NSAIDs
treat the driver → AKI, acidosis, constipation, tissue breakdown, poor glycemic control
repeat K⁺ on a non-hemolyzed sample; 12-lead ECG + monitoring if unwell or rising fast
no calcium, insulin-glucose or binder at this band unless ECG changes

K⁺ ≥ 6.0 or ECG changes: treatment pathway

protect the heart (ECG changes, at any K⁺)
- calcium gluconate 10% 30 mL IV over 10 min (6.8 mmol Ca; large vein, cardiac monitoring); arrest or peri-arrest: calcium chloride 10% 10 mL over 5 min instead
- repeat ECG at 5–10 min; repeat the dose if changes persist (onset ~3 min, lasts ~30–60 min)
shift K⁺ into cells (K⁺ ≥ 6.0, or ECG changes at any K⁺)
- Actrapid 10 units IV in glucose 25 g (D50% 50 mL, or D20% 125 mL) over 15–30 min, not bolus
- salbutamol 10–20 mg nebulized as an adjunct, never alone (caution: tachycardia)
- sodium bicarbonate → not routine
remove K⁺ (K⁺ ≥ 6.5: give · 6.0–6.4: consider · any ongoing source)
- Lokelma 10 g PO TDS for up to 72 h (onset ~1 h)
- no Lokelma → Veltassa 8.4 g PO once daily (onset 4–7 h)
- neither replaces steps 1–2 · escalate early

glucose every 30 min for 2 h then hourly to 6 h; the D50% 50 mL with the insulin is the treatment dose, not cover; pre-treatment glucose < 7 → D10% 250 mL IV at 50 mL/h after the insulin
K⁺ at 1, 2, 4, 6 and 24 h (rebound as insulin wears off); monitor while K⁺ ≥ 6.5 or ECG changes; stop offending drugs
refractory, anuric, or dialysis patient with K⁺ ≥ 6.5 → nephrology for dialysis; no renal service on site → ICU
hand over → last K⁺ + time, next check due, escalation trigger

potassium replacement

product	potassium content	usual adult dose	bedside note
IV KCl 15%	2 mmol/mL: 10 mL ampoule = 20 mmol K⁺	by band (treat table): 20–40 mmol in 200–400 mL NaCl 0.9% over 2–4 h, i.e. 10 mmol/h	never undiluted or bolus; dilute at least 50× (SmPC); max 20 mmol/h, monitored; peripheral ≤ 40 mmol/L unless monitored (box above)
IV potassium phosphate	15 mL = 45 mmol PO₄ + 66 mEq K⁺ (4.4 mEq K⁺ per mL)	dosed by phosphate, not potassium: see phosphate	use only when phosphate is also low; counts toward the potassium total
oral Slow-K 600 mg	8 mmol K⁺ per tablet (SmPC)	1–2 tabs TDS (treat table); SmPC maintenance 2–3 tabs/day	swallow whole with food and water, never crush; NGT → KCl syrup
oral KCl syrup 6.6%	~1.3 mmol per 1.5 mL (≈ 0.9 mmol/mL)	dose by mmol required, divided, with fluids	use for NGT or when tablets not tolerated; local formulation strength verification needed
oral potassium citrate syrup	~6.6 mEq per 5 mL	dose by mEq required, divided	alkalinizing salt: hypokalemia with metabolic acidosis; local formulation verification needed

potassium-lowering agents

product	usual adult dose	onset	bedside note
Calcium Resonium	15 g PO 3–4 times daily in water or syrup (not fruit juice); or 30 g rectal retention enema daily (SmPC)	hours to days	UKKA 2023: no longer routinely recommended for acute hyperkalemia; separate other oral drugs by ≥ 3 h; constipation
Resonium A	15 g PO 3–4 times daily; or 30 g rectal daily (SmPC)	hours to days	sodium load; stop when K⁺ falls to 5 mmol/L
Lokelma (sodium zirconium cyclosilicate)	10 g PO TDS up to 72 h, then 5–10 g once daily	~ 1 h	preferred on-call binder (UKKA 2023, K⁺ ≥ 6.0); delayed-onset: not a substitute for emergency therapy
Veltassa (patiromer)	8.4 g PO once daily; titrate by 8.4 g at ≥ 1-week intervals; max 25.2 g/day (SmPC)	4–7 h	UKKA 2023: an option at K⁺ ≥ 6.0 when Lokelma is unavailable, otherwise chronic use; delayed-onset: never in place of calcium / insulin-glucose; separate other oral drugs by 3 h

Lokelma and Veltassa are delayed-onset agents and are not substitutes for emergency therapy (calcium, insulin-glucose, salbutamol, dialysis) in life-threatening hyperkalemia

source	type
UK Kidney Association (UKKA) hyperkalemia guideline, 2023	international guideline

Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.

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reviewed Aug 2026updated Oct 2026file lab/rft-potassium