Ep 181 – Management of hyperkalaemia in primary care

In this episode, Dr Hannah Rosa and Dr Will Hinchliffe (Consultant in Renal and General Medicine working in the north-east and north Cumbria) discuss the management of hyperkalaemia in primary care. They break the management down into six steps, so that when you are next faced with blood test results that show a raised potassium level, you will know exactly what to do. They first discuss who needs admission into hospital, then how to manage hyperkalaemia in the community and finally the role of potassium binders.

Key take-home points

• Hyperkalaemia is when the level of potassium in the blood is too high, typically 5.5 mmol/L or more.
• High potassium can cause muscle weakness, dangerous cardiac arrhythmias and even cardiac arrest.
• At-risk groups include those with chronic kidney disease (CKD), heart failure or diabetes and those on renin-angiotensin-aldosterone system inhibitors (RAASi), such as ACE inhibitors, angiotensin receptor blockers and potassium-sparing diuretics (such as spironolactone).

Management steps

• Step 1. Review how high the potassium is.
  • Mild hyperkalaemia is 5.5–5.9 mmol/L
  • Moderate is 6.0–6.4 mmol/L
  • Severe is 6.5 mmol/L or greater
  • If potassium is ≥6.5, then in most cases we should advise the patient to urgently go to hospital.
• Step 2. Check for acute kidney injury.
  • Acute kidney injury is diagnosed if there is either:
    • A serum creatinine rise of 26 μmol/L or greater within 48 hours, or
    • A 50% or greater increase within 7 days, compared to a known baseline.
  • If there is a mild or moderate rise in potassium and acute kidney injury, then again we should advise the patient to urgently go to hospital.
• Step 3. Determine if the patient is symptomatic of hyperkalaemia.
  • Symptoms include:
    • Palpitations
    • Syncope
    • Nausea
    • Muscle pain
    • Weakness
    • Dyspnoea
    • Paraesthesia.
  • If the patient is symptomatic, then in most cases, we need to advise them to attend hospital.
• Step 4. Consider the cause and review for risk factors for hyperkalaemia.
  • Risk factors are:
    • CKD
    • Heart failure
    • Diabetes
    • Taking a RAASi.
  • Also review diet and other non-RAASi medications which can cause hyperkalaemia, such as:
    • Trimethoprim
    • Non-selective beta-blockers such as propranolol
    • Laxatives which contain potassium salts, such as Movicol
    • Potassium supplements
    • Digoxin – with toxicity.
• Step 5. Review the RAASi dose and repeat the blood test.
  • If the patient does not have any risk factors for hyperkalaemia:
    • Mild hyperkalaemia – repeat within 5 working days
    • Moderate hyperkalaemia – repeat again within 24 hours.
  • If the patient has strong risk factors for hyperkalaemia: 
    • Mild hyperkalaemia – repeat within the next 14 days
      • RAASi:
        • For hypertension alone, stop the RAASi and use an alternative
        • For CKD with albuminuria or heart failure with reduced ejection fraction, maintain the same dose
      • If the repeat potassium is: 
        • <5.5 mmol/L – continue to optimise the RAASi dose
        • 5.5–5.9 mmol/L – maintain the RAASi dose
        • 6.0–6.4 mmol/L – suspend the RAASi and discuss initiation of a potassium binder with the renal team
        • ≥6.5 mmol/L – refer to hospital
    • Moderate hyperkalaemia – repeat within the next 7 days. 
      • RAASi:
        • For hypertension alone, stop the RAASi and use an alternative
        • For CKD with albuminuria or heart failure with reduced ejection fraction, halve the RAASi dose
      • If the repeat potassium is: 
        • <5.5 mmol/L – continue to optimise the RAASi dose
        • 5.5–5.9 mmol/L – maintain the lower RAASi dose
        • 6.0–6.4 mmol/L – suspend the RAASi and discuss initiation of a potassium binder with the renal team
        • ≥6.5 mmol/L – refer to hospital.
• Step 6. Consider a potassium binder.
  • These drugs can help keep patients with CKD and heart failure on their RAASi drugs for longer, reducing their risk of cardiovascular events.
  • NICE has approved two potassium binders (patiromer and sodium zirconium cyclosilicate) in selected patients with CKD stages 3b to 5 (not on dialysis) or heart failure if they have confirmed persistent hyperkalaemia with a serum potassium of ≥6 mmol/L and are not receiving an optimal dose of a RAASi.

Key references

1. NICE. 2024. https://www.nice.org.uk/guidance/ng148. 
2. British National Formulary. https://bnf.nice.org.uk/treatment-summaries/hyperkalaemia/. 
3. UK Kidney Association. 2023. https://www.ukkidney.org/sites/default/files/FINAL%20VERSION%20-%20UKKA%20CLINICAL%20PRACTICE%20GUIDELINE%20-%20MANAGEMENT%20OF%20HYPERKALAEMIA%20IN%20ADULTS%20-%20191223_0.pdf.
4. Medscape. 2025. https://img.medscapestatic.com/vim/live/professional_assets/medscape/prof_documents/CKDHackInterventionsMay2025v3.pdf.
5. Kidney Disease Improving Global Outcomes. 2024. https://kdigo.org/wp-content/uploads/2024/03/KDIGO-2024-CKD-Guideline.pdf.
6. NICE. 2022. https://www.nice.org.uk/guidance/ta599.
7. NICE. 2020. https://www.nice.org.uk/guidance/TA623.
8. International Society of Nephrology. https://www.theisn.org/initiatives/toolkits/raasi-toolkit/#Challenges.

Resources

1. Kidney Care UK. https://kidneycareuk.org/get-support/healthy-diet-support/patient-info-lowering-your-potassium-levels/.