Sodium Polystyrene Sulfonate
Also known as: Kayexalate · Kionex · SPS · Elutit-Natrium · KExit · Kexelate · Resinsodio · Resonium A · natrii polystyrenesulfonas · sodium polystyrene sulphonate
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hyperkalemia | 2 grams of resin/kg divided into 3 daily doses (suspended in 3-4 mL water/gram or commercial suspension). Severe hyperkalemia: 3-4 times the normal amount may be given. | PO/Enema | q8h | As needed | 🌎 NA |
| Mild hyperkalemia (<6 mEq/L) | 2 grams/kg in 3-4 divided doses with 20% sorbitol | PO/Enema | q6-8h | As needed | 🌎 NA |
- Hyperkalemia: If PO, give with a cathartic. If enema, do NOT use a cathartic (must retain in colon for at least 30 mins). Enema prep: add 15g per 100 mL of 1% methylcellulose or 10% dextrose.
- Mild hyperkalemia (<6 mEq/L): May also be given as an enema without sorbitol.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Life-threatening hyperkalemia in neonatal foals | 15 grams of resin in 100 mL of 10% dextrose | Enema | Once/As directed | As needed | 🌎 NA |
- Life-threatening hyperkalemia in neonatal foals: Monitor serum potassium and sodium closely.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Sodium Polystyrene Sulfonate (SPS) is a non-absorbable cation exchange resin used primarily as an adjunctive treatment for hyperkalemia (high blood potassium levels) in veterinary patients.
Clinical Pearl: Because its onset of action is slow (hours to days), SPS should not be used as the sole therapy for acute, life-threatening hyperkalemia. Faster-acting therapies (e.g., IV calcium gluconate, regular insulin with dextrose, or sodium bicarbonate) should be prioritized in emergencies.
Key points:
- It works by exchanging sodium ions for potassium ions in the gastrointestinal tract.
- It is often administered with a cathartic (like sorbitol) when given orally to prevent constipation and expedite the removal of the resin-potassium complex.
- The underlying cause of the hyperkalemia (e.g., acute kidney injury, urinary obstruction, hypoadrenocorticism) must always be identified and treated concurrently.
Mechanism of action
SPS acts as a cation exchange resin in the gastrointestinal tract.
- Mechanism: After oral or rectal administration, the resin exchanges its sodium ions for hydrogen ions in the acidic environment of the stomach. As it travels into the large intestine, where potassium concentration is higher, it exchanges these ions for potassium ions.
- Binding Capacity: While theoretically capable of exchanging up to 3.1 mEq of potassium per gram, in vivo it typically exchanges approximately 1 mEq of potassium per gram of resin.
- Excretion: The resin, now bound to potassium, is excreted unchanged in the feces, thereby physically removing potassium from the body.
- Sodium Load: Because it releases sodium in exchange for potassium, it delivers a significant sodium load to the patient, which can be problematic in sodium-restricted individuals.
Safety & warnings
Contraindications
- Patients on severely restricted sodium diets
- Severe congestive heart failure (CHF)
- Severe hypertension
- Oliguric or anuric acute kidney injury (where sodium load cannot be excreted)
- Conditions predisposing to severe constipation or bowel obstruction
Adverse effects
- Constipation (fecal impaction reported rarely)
- Anorexia
- Vomiting
- Nausea
- Hypokalemia (from overuse)
- Hypocalcemia
- Hypomagnesemia
- Sodium retention / Hypernatremia
Precautions
Because large quantities of sodium may be released and absorbed during the exchange process, use with extreme caution in patients requiring sodium restriction (e.g., severe CHF, hypertension).
Overdosage or prolonged use can lead to severe electrolyte derangements, specifically hypokalemia, hypocalcemia, and hypomagnesemia.
When given orally, it is generally mixed with a cathartic (like 70% sorbitol) to hasten transit time and prevent severe constipation or fecal impaction. However, do not use a cathartic if administering as a retention enema, as the resin must remain in the colon for at least 30 minutes to be effective.
Drug interactions
SPS may bind with magnesium or calcium, preventing bicarbonate ion neutralization and potentially leading to systemic metabolic alkalosis. Concurrent use is not recommended.
Similar to antacids, can lead to metabolic alkalosis and reduced potassium-binding efficacy.
Monitoring
- Serum electrolytes (sodium and potassium at least once daily; calcium, magnesium)
- Acid/base status
- ECG (if warranted to monitor cardiac effects of hyper/hypokalemia)
- Fecal output and consistency (monitor for constipation/impaction)
Pharmacokinetics
Absorption
SPS is not absorbed from the gastrointestinal tract.
Distribution
Remains localized within the lumen of the gastrointestinal tract.
Metabolism
Not metabolized. Acts locally via ion exchange.
Elimination
Excreted unchanged in the feces, carrying bound potassium and other cations with it.
Overdose
Overdosage or overuse may lead to severe electrolyte imbalances, including hypokalemia (low potassium), hypocalcemia (low calcium), and hypomagnesemia (low magnesium), as well as significant sodium retention.
Treatment is symptomatic and supportive. Discontinue the drug immediately and correct electrolyte deficits based on frequent serum chemistry monitoring.
Available products
Formulations
- Powder for suspension
- Oral/Rectal suspension
Human-labeled
- Sodium Polystyrene Sulfonate Powder: approx 100 mg (4.1 mEq) sodium per gram (1 lb jars & 454 g)
- Sodium Polystyrene Sulfonate Suspension: 15 grams/60 mL (sodium 1.5 grams, 65 mEq) in various sizes
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store products in well-closed containers at room temperature; do not heat. Suspensions made from powder should be freshly prepared and used within 24 hours.
Client information
Sodium Polystyrene Sulfonate is used to help lower dangerously high potassium levels in your pet's blood.
- Administration: This medication can be given by mouth or as an enema. If given by mouth, it is often mixed with a sweet liquid (sorbitol) to help it move through the digestive tract and prevent constipation. Shake liquid suspensions very well before each use.
- Side Effects: Watch for signs of constipation, loss of appetite, vomiting, or nausea. Contact your veterinarian if your pet stops having bowel movements.
- Interactions: Do not give your pet over-the-counter antacids or laxatives (especially those containing calcium or magnesium, like Milk of Magnesia) while they are taking this medication, as it can cause dangerous changes in blood chemistry.
- Follow-up: Your pet will need frequent blood tests to ensure their potassium and sodium levels remain in a safe range.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.