SODIUM POLYSTYRENE SULFONATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SODIUM POLYSTYRENE SULFONATE (SODIUM POLYSTYRENE SULFONATE).
Sodium polystyrene sulfonate is a cation-exchange resin that exchanges sodium ions for potassium ions in the gastrointestinal tract, primarily in the large intestine, thereby reducing serum potassium levels.
| Metabolism | Sodium polystyrene sulfonate is not absorbed systemically; it acts locally in the gastrointestinal tract. |
| Excretion | Primarily fecal (via gut) as the resin is not absorbed. Only a small fraction (approximately 0.5-1% of the administered dose) is absorbed, and the absorbed portion is eliminated renally as the sulfonate moiety. Renal elimination contributes minimally to total clearance (<1%). |
| Half-life | The terminal elimination half-life of the absorbed fraction is not well-defined due to minimal systemic absorption; hence, half-life is not clinically relevant. The resin itself is not eliminated from the body via metabolism or excretion but is passed in feces. |
| Protein binding | Negligible (<1%). The resin is not absorbed; therefore, protein binding of the intact resin is not applicable. The absorbed sulfonate moiety has negligible protein binding. |
| Volume of Distribution | Not applicable (Vd essentially 0 for the resin as it remains in the GI tract). For the absorbed fraction, Vd is minimal (<0.1 L/kg) due to rapid renal excretion. |
| Bioavailability | Oral: Essentially 0% absorbed (non-absorbable resin). Rectal: Similarly, systemic absorption is negligible (<0.5%). |
| Onset of Action | Oral: 2-12 hours. Rectal (enema): 2-4 hours. The onset varies based on gut motility and stool transit time. |
| Duration of Action | Oral: Effect lasts up to 4-6 hours after a single dose; repeated doses are needed for sustained potassium lowering. Rectal: Duration is shorter, typically 2-4 hours. Note: The drug exchanges sodium for potassium in the gut lumen, and clinical effect lasts as long as the resin is in contact with gastrointestinal contents. |
Adults: 15 g orally once daily to four times daily, as a single dose or suspension in water or syrup (3-4 mL per gram of resin). May also be administered rectally as a retention enema: 30-50 g every 6-8 hours, retained for at least 30-60 minutes.
| Dosage form | SUSPENSION |
| Renal impairment | No specific dose adjustment is recommended based on GFR; however, use with caution in patients with renal impairment due to risk of electrolyte abnormalities and colonic necrosis. Alternative potassium-lowering agents are preferred in severe renal disease. |
| Liver impairment | No specific Child-Pugh-based dose modifications are established. Use with caution in patients with hepatic impairment due to potential for fluid and electrolyte disturbances. |
| Pediatric use | Children: 1 g/kg orally per dose, given 1-4 times daily, or rectally as a retention enema: 1 g/kg per dose every 6-8 hours. Adjust based on serum potassium levels and body weight. |
| Geriatric use | Elderly patients may be more susceptible to electrolyte imbalances and dehydration. Use the lowest effective dose and monitor serum potassium and sodium closely. Consider alternative therapy if risk of bowel ischemia or constipation is high. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SODIUM POLYSTYRENE SULFONATE (SODIUM POLYSTYRENE SULFONATE).
| Breastfeeding | Not absorbed systemically; excretion into breast milk is unlikely. However, consider potential effects on infant electrolyte balance if maternal electrolyte disturbances occur. No M/P ratio available; use with caution in breastfeeding women. |
| Teratogenic Risk | No adequate studies in pregnant women. Animal reproduction studies not conducted. Sodium polystyrene sulfonate is not absorbed systemically, so fetal exposure is minimal. However, potential maternal electrolyte disturbances (e.g., hypokalemia) may indirectly affect the fetus. Risk cannot be ruled out; use only if clearly needed. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to sodium polystyrene sulfonate or any component","Obstructive bowel disease","Neonates with reduced gut motility (especially when given with sorbitol)","Severe hypokalemia"]
| Precautions | ["Risk of intestinal necrosis, particularly with concomitant use of sorbitol","Electrolyte disturbances (hypokalemia, hypocalcemia, hypomagnesemia)","Sodium overload in patients with heart failure or hypertension","Use with caution in patients with severe constipation or impaction","Potential for aspiration if given orally to patients with impaired gag reflex"] |
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| Fetal Monitoring | Monitor serum potassium, calcium, and magnesium levels regularly during therapy. Assess for signs of electrolyte imbalance (e.g., cardiac arrhythmias, muscle weakness). Fetal monitoring not specifically required but maternal stability important. |
| Fertility Effects | No known effects on fertility. No human or animal data available. |