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Hyperkalaemia

Lab results

Guidance changed 1 Jul 2026. UK Kidney Association update: IV calcium evidence downgraded to a suggestion; calcium resonium no longer used.

Severity (UKKA): mild 5.5–5.9, moderate 6.0–6.4, severe ≥6.5 mmol/L.

Exclude a spurious result (haemolysis, delay, drip arm) — but never delay treatment if ECG changes or K⁺ ≥6.5.

Act now

  1. 1

    Step 1 — protect the heart if ECG changes: IV calcium.

  2. 2

    Step 2 — shift K⁺ into cells: insulin-glucose (recommended for severe, suggested for moderate) plus nebulised salbutamol as an adjunct.

  3. 3

    Step 3 — remove K⁺: sodium zirconium cyclosilicate (SZC) for severe; consider for moderate.

  4. 4

    Stop K⁺-containing fluids and culprit drugs.

Assess

  • ABCDE. 12-lead ECG urgently for K⁺ ≥6.0 (peaked T, flat P, broad QRS, sine wave, brady/arrhythmia).
  • Continuous cardiac monitoring for K⁺ ≥6.5, any ECG changes, or K⁺ 6.0–6.4 in an unwell patient.
  • Causes: AKI/CKD, drugs (ACEi/ARB, spironolactone, NSAIDs, trimethoprim, K⁺ supplements, heparin), acidosis, tissue breakdown.

Investigations

  • Repeat K⁺ at 1, 2, 4, 6 and 24 hours after treating moderate or severe hyperkalaemia (watch for rebound).
  • Capillary glucose after insulin-glucose: 0, 30, 60, 90, 120, 180, 240, 300 and 360 minutes.
  • U&E, venous gas (pH, bicarbonate), CK if rhabdomyolysis possible.

Manage

  • Treat the cause; review RAAS inhibitors once stable rather than stopping long term without a plan.
  • IV sodium bicarbonate is not routinely suggested; calcium resonium no longer recommended in the acute setting.

Escalate when

  • Severe hyperkalaemia: urgent renal or critical care opinion (critical care first if no on-site renal service).
  • Haemodialysis patients with severe hyperkalaemia need urgent dialysis.
  • ABC or consciousness problems: critical care.

Doses and prescribing

IV calcium (6.8 mmol): 30 mL 10% calcium gluconate over 10 minutes, or 10 mL 10% calcium chloride over 5 minutes (chloride preferred in cardiac arrest/peri-arrest). Repeat if ECG changes persist. Caution with digoxin.

Insulin-glucose: 10 units soluble insulin with 25 g glucose IV over 15 minutes (e.g. 50 mL 50% or 125 mL 20% — use local preparation).

If pre-treatment glucose <7.0 mmol/L: follow with 10% glucose at 50 mL/h for 5 hours (25 g).

Salbutamol

10–20 mg nebulised — adjunct only, never monotherapy for severe hyperkalaemia.

SZC

10 g three times daily for up to 72 hours. Patiromer 8.4 g is an alternative for K⁺ ≥6.0 (not available in Scotland per UKKA).

Check the BNF and your local formulary before prescribing.

Written to current guidance · sources checked 14 Nov 2026. We watch NICE for updates weekly.

Sources (2)

Reviewed by Aboodee Alhasso, MPharm MRCPharm IP on 14 Nov 2026

For healthcare professionals, as an aid to clinical judgement — not a substitute for it. Follow your local policy and ask a senior when in doubt.