SODIUM POLYSTYRENE SULFONATE
Clinical safety rating
cautionComprehensive clinical and safety monograph for SODIUM POLYSTYRENE SULFONATE (SODIUM POLYSTYRENE SULFONATE).
Comprehensive clinical and safety monograph for SODIUM POLYSTYRENE SULFONATE (SODIUM POLYSTYRENE SULFONATE).
Treatment of hyperkalemia
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. |
| Molecular Weight | 1000 |
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 | Sodium polystyrene sulfonate is not absorbed systemically; therefore, no fetal risk is expected. However, use only if clearly needed due to potential maternal electrolyte disturbances (e.g., hypokalemia) that could affect the fetus. |
| 2nd trimester | Same as trimester 1. No known teratogenicity due to lack of absorption. Monitor maternal potassium levels to avoid hypokalemia. |
| 3rd trimester | Same as trimester 1 and 2. Use with caution near delivery due to potential for maternal electrolyte imbalances that could affect neonatal outcomes. |
Clinical note
Comprehensive clinical and safety monograph for SODIUM POLYSTYRENE SULFONATE (SODIUM POLYSTYRENE SULFONATE).
| Placental transfer | No significant placental transfer due to lack of systemic absorption. |
| Breastfeeding | Sodium polystyrene sulfonate is not absorbed from the gastrointestinal tract, so breastfeeding is considered safe. However, monitor maternal electrolytes as hypokalemia could affect milk production and composition. |
| Lactation Rating | L1 - Safe |
| 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. |
| 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. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Obstructive bowel diseaseNeonates with reduced gut motility (risk of impaction)Hypokalemia (serum potassium < 3.5 mEq/L)HypocalcemiaConcurrent use of sorbitol (risk of intestinal necrosis)
| 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 |
| Food/Dietary | Avoid foods high in potassium (e.g., bananas, oranges, potatoes, spinach, avocados) and high-sodium foods to optimize potassium removal and prevent sodium overload. Do not mix SPS with juices containing potassium (e.g., orange juice). Maintain adequate fluid intake unless fluid-restricted. Avoid laxative use. No specific interaction with alcohol, but excess alcohol can affect electrolyte balance. |
| Clinical Pearls | Sodium polystyrene sulfonate (SPS) exchanges sodium for potassium in the colon. Onset of action is 2-12 hours (oral) or 30-60 minutes (rectal). Monitor for hypokalemia, hypomagnesemia, and sodium overload, especially in patients with renal impairment, heart failure, or hypertension. Do not administer orally in patients with impaired bowel motility (e.g., postoperative ileus, constipation) due to risk of colonic necrosis. Concurrent use with sorbitol increases risk of intestinal necrosis; avoid sorbitol-containing formulations. SPS is less effective than newer potassium binders (patiromer, sodium zirconium cyclosilicate). Rectal administration is preferred when rapid effect needed, but ensure enema is retained for at least 30-60 minutes. Each gram of SPS exchanges approximately 1 mEq of potassium but also delivers 1 mEq of sodium, which can worsen fluid overload. |
| Patient Advice | Take this medication exactly as prescribed, usually 1 to 4 times daily. · For oral suspension, mix the powder with water or another liquid (not juice) as directed and drink immediately. Do not mix with orange juice or other potassium-containing liquids. · Do not take this medication within 3 hours of any other oral medication to prevent absorption issues. · This medication may cause constipation or stomach upset. Tell your doctor if you have severe constipation, rectal bleeding, or severe stomach pain. · Avoid using laxatives or stool softeners unless directed by your doctor due to increased risk of bowel problems. · This drug exchanges sodium for potassium, so it may increase your sodium levels. Monitor salt intake if you have high blood pressure or heart failure. · Contact your doctor immediately if you experience muscle weakness, irregular heartbeat, or signs of low potassium (e.g., confusion, leg cramps). · Keep this medication out of reach of children and do not use if the powder has changed color or consistency. |
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