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Hyperkalaemia Pregnancy: Use with caution — sodium load and potential electrolyte disturbances; use only if essential

Sodium Polystyrene Sulfonate

Brand names: Resonium A

Adult dose

Dose: 15 g three to four times daily (oral or via nasogastric tube). Rectal: 30 g as retention enema in 100 mL water.
Route: Oral or rectal
Frequency: Three to four times daily (oral); once daily retention enema (rectal)
Max: 60 g/day
Cation exchange resin — exchanges sodium for potassium in the GI tract. Largely superseded by patiromer (Veltassa) and sodium zirconium cyclosilicate (Lokelma) which have faster onset and better tolerability. Resonium A remains an option where newer agents unavailable.

Paediatric dose

Dose: 1 g/day/kg
Route: Oral or rectal
Frequency: Divided doses
Max: Per body weight
Use with caution in neonates — intestinal necrosis cases reported (especially post-operatively). BNFc guidance recommends caution.

Dose adjustments

Renal

No dose adjustment required — used in CKD and dialysis patients for hyperkalaemia management

Hepatic

No dose adjustment required

Paediatric weight-based calculator

Use with caution in neonates — intestinal necrosis cases reported (especially post-operatively). BNFc guidance recommends caution.

Clinical pearls

  • Resonium A vs newer agents: sodium zirconium cyclosilicate (Lokelma) works within 1 hour and is now NICE-recommended first-line for hyperkalaemia requiring rapid correction. Patiromer works over 4-7 hours — for chronic management. Resonium A has slow onset (hours to days) and poorer tolerability.
  • Intestinal necrosis: rare but potentially fatal — particularly reported with sorbitol-containing formulations and in post-operative/immunocompromised patients. FDA removed sorbitol from US Kayexalate labelling in 2011 for this reason.
  • Sodium load: each 15 g dose of Resonium A releases approximately 1.5 g sodium (65 mmol). In fluid-overloaded or hypertensive CKD/dialysis patients this sodium load can worsen oedema and hypertension — use patiromer or SZC preferentially.
  • Constipation management: prescribe lactulose or Movicol alongside Resonium A — resin causes severe constipation which reduces adherence and efficacy. Do NOT use sorbitol-containing laxatives with Resonium A (intestinal necrosis risk).
  • Emergency hyperkalaemia (K+ >6.5 mmol/L or ECG changes): ion exchange resins are NOT appropriate for emergency management. Use IV calcium gluconate (membrane stabilisation), insulin + dextrose, salbutamol nebulisation, and consider emergency dialysis first.

Contraindications

  • Obstructive bowel disease
  • Post-operative patients (intestinal necrosis risk — especially neonates)
  • Hypokalemia
  • Hypersensitivity to polystyrene

Side effects

  • Constipation (use lactulose/sorbitol alongside, but see note on sorbitol)
  • Nausea/vomiting
  • Intestinal necrosis (rare — case reports, especially rectal route in post-operative patients)
  • Sodium overload (each resin dose releases sodium — caution in heart failure and fluid-overloaded CKD patients)
  • Hypomagnesaemia, hypocalcaemia

Interactions

  • Antacids and laxatives — bind to resin; reduce absorption of other drugs; give medications 3 hours before or after Resonium
  • Digoxin — hypokalaemia potentiates digoxin toxicity; if K+ falls below target, digoxin toxicity risk increases

Monitoring

  • Potassium (daily while K+ elevated; then twice weekly)
  • Sodium (sodium overload)
  • Magnesium and calcium
  • Bowel function
  • ECG if K+ >6.0 mmol/L

Reference: BNFc; BNF 90; BNFc; NICE NG35 (Acute Hyperkalaemia); SPC Resonium A; FDA Advisory (Sorbitol + SPS Intestinal Necrosis). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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