SPS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SPS (SPS).
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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SPS (SPS).
| Breastfeeding | Excretion into breast milk is unlikely due to non-absorbable nature. M/P ratio not applicable. Considered compatible with breastfeeding, but monitor infant for electrolyte disturbances if maternal use is prolonged. |
| 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. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypokalemia","Obstructive bowel disease","Neonates with reduced gut motility (postoperative or drug-induced)","Concurrent use with sorbitol"]
| 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"] |
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| 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). |