SPS
Clinical safety rating
cautionComprehensive clinical and safety monograph for SPS (SPS).
Comprehensive clinical and safety monograph for SPS (SPS).
Treatment of hyperkalemia
SPS (sodium polystyrene sulfonate) is a cation-exchange resin that exchanges sodium ions for potassium ions in the gastrointestinal tract, primarily in the colon, thereby reducing serum potassium levels.
| Metabolism | SPS is not absorbed systemically and is excreted unchanged in the feces. |
| Excretion | SPS (sodium polystyrene sulfonate) is a cation-exchange resin that is not absorbed systemically. It is excreted entirely in the feces, with no renal or biliary elimination. The resin-bound potassium is eliminated via the gastrointestinal tract. |
| Half-life | Not applicable; SPS acts locally in the gastrointestinal tract and does not undergo systemic absorption. No terminal half-life can be defined. |
| Protein binding | Not applicable; SPS is not absorbed and does not bind to plasma proteins. |
| Volume of Distribution | Not applicable; SPS remains within the gastrointestinal lumen and does not distribute into body tissues. Reported Vd is negligible. |
| Bioavailability | Oral: 0% (not absorbed); rectal: 0% (not absorbed). SPS acts locally without systemic availability. |
| Onset of Action | Oral: 2–12 hours. Rectal enema: 1–4 hours. Onset depends on gastrointestinal motility and the rate of ion exchange. |
| Duration of Action | Oral: 4–6 hours (variable). Rectal: shorter duration than oral. Duration is limited by the residence time of the resin in the intestine and the rate of potassium removal. Repeated doses may be required. |
| Molecular Weight | 2000 |
15-60 g orally 1-4 times daily; administer as a suspension in water or juice. Alternatively, 30-50 g rectally as a retention enema every 6 hours.
| Dosage form | SUSPENSION |
| Renal impairment | No specific dose adjustment is recommended based on GFR. Use with caution in patients with renal impairment due to risk of electrolyte disturbances (e.g., hypernatremia, hypokalemia). |
| Liver impairment | No dose adjustment required for hepatic impairment. Monitor serum electrolytes and fluid balance in patients with hepatic disease. |
| Pediatric use | Children (2-12 years): 0.5-2 g/kg/day divided every 4-6 hours; maximum 30 g/day. Administer orally or rectally as per adult guidance. |
| Geriatric use | Use lowest effective dose; monitor electrolyte levels and renal function more frequently due to age-related decline in renal function and increased risk of electrolyte imbalance. |
| 1st trimester | Limited human data; avoid unless benefit outweighs risk. Crosses placenta. |
| 2nd trimester | Use with caution; potential for electrolyte disturbances and colonic ulceration. |
| 3rd trimester | Avoid near term due to risk of fluid and electrolyte imbalance. |
Clinical note
Comprehensive clinical and safety monograph for SPS (SPS).
| Placental transfer | Crosses placenta; extent unknown but likely low due to high molecular weight. |
| Breastfeeding | Excreted in breast milk in minimal amounts; unlikely to cause adverse effects in infant. However, use with caution due to potential for gastrointestinal effects. |
| Lactation Rating | L2 |
| Teratogenic Risk | SPS (sodium polystyrene sulfonate) is not absorbed systemically; therefore, no direct fetal risk is expected. However, electrolyte disturbances (e.g., hypokalemia, hypocalcemia) from maternal use could indirectly affect the fetus. First trimester: No known teratogenic effects. Second/Third trimester: Risk of maternal electrolyte imbalance may impact fetal development. Use only if clearly needed. |
| Fetal Monitoring | Monitor maternal serum potassium, calcium, and magnesium levels regularly. Assess for signs of hypokalemia (ECG changes, muscle weakness). In fetus, consider monitoring for bradycardia or arrhythmias if maternal electrolyte disturbances occur. |
| Fertility Effects | No direct effects on fertility reported; potential indirect impact from electrolyte imbalances affecting hormonal regulation (theoretical). |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to sodium polystyrene sulfonate or any componentObstructive bowel diseaseNeonates with reduced gut motility
| Precautions | Risk of intestinal necrosis, particularly with concomitant use of sorbitol, Electrolyte disturbances (e.g., hypokalemia, hypocalcemia, hypernatremia), Use with caution in patients with gastrointestinal disorders or postoperative patients |
| Food/Dietary | Avoid high-potassium foods such as bananas, oranges, tomatoes, potatoes, and spinach to prevent excessive potassium intake. SPS may bind to some foods, but no specific food restrictions beyond potassium-rich foods are required. Do not mix SPS with fruit juices; use only water or simple syrup. |
| Clinical Pearls | SPS (sodium polystyrene sulfonate) is a potassium-lowering resin that exchanges sodium for potassium in the GI tract. Administer orally or as a retention enema. Monitor for hypokalemia, hypomagnesemia, and sodium overload. Contraindicated in patients with bowel obstruction, severe constipation, or postoperative ileus due to risk of intestinal necrosis. Use with caution in patients on NSAIDs or with risk of colonic necrosis. Do not mix with sorbitol; use of sorbitol increases risk of intestinal necrosis. Monitor serum potassium levels frequently. |
| Patient Advice | Take this medication exactly as prescribed, usually 1 to 4 times a day. · Do not mix SPS with orange juice or other fruit juices; it should be mixed with water or syrup. · This medication may cause constipation, so drink plenty of fluids and eat high-fiber foods. · If you experience severe constipation, severe abdominal pain, vomiting, or blood in vomit or stool, seek medical attention immediately. · Avoid taking other medications within 3 hours of SPS as it may bind to them and reduce their effectiveness. · Inform your doctor if you have a history of bowel obstruction, constipation, or kidney disease. · Do not use sorbitol or other laxatives with SPS unless directed by your doctor. |
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