Calcium Polystyrene Sulfonate

Usage

• Calcium Polystyrene Sulfonate is prescribed for the treatment of hyperkalemia (high potassium levels in the blood). It’s particularly useful in patients with renal insufficiency or those undergoing dialysis.
• Pharmacological classification: Potassium-removing agent, cation-exchange resin.
• Mechanism of Action: Calcium Polystyrene Sulfonate works by exchanging calcium ions for potassium ions in the digestive tract, primarily the large intestine. The resin binds potassium, which is then eliminated from the body through the stool, thereby lowering serum potassium levels.

Alternate Names

• Polystyrene sulfonate calcium
• Calcium Resonium
• Brand Names: Kchek, Kalimate, Resonium Calcium, K-Bind, Statkal, and various others depending on the region.

How It Works

• Pharmacodynamics: Calcium Polystyrene Sulfonate exchanges calcium for potassium in the intestine, leading to a reduction in serum potassium levels. The efficiency of this exchange can vary. It is not entirely selective for potassium and may also bind other cations like magnesium.
• Pharmacokinetics: The resin itself is not absorbed systemically. It remains within the gastrointestinal tract, where the ion exchange occurs. The bound potassium is then eliminated in the feces. The calcium released from the resin may be partially absorbed.
• Mode of Action: The sulfonate groups on the resin have a negative charge, attracting positively charged cations like potassium. As the resin travels through the digestive tract, potassium ions in the intestinal lumen bind to the resin, replacing the calcium ions initially present on the resin. This exchange facilitates the removal of potassium from the body. There is no receptor binding, enzyme inhibition, or neurotransmitter modulation involved.
• Elimination pathways: The resin itself, along with bound potassium, is eliminated via fecal excretion. There is no renal or hepatic metabolism involved.

Dosage

Standard Dosage

Adults:

• Oral: 15g three or four times a day, mixed with water or syrup (avoid fruit juices). Administer at least 3 hours before or after other oral medications.
• Rectal: 30g in 150 mL of water or 10% dextrose, administered as a retention enema.

Children:

• Oral: 1 g/kg body weight daily, divided into multiple doses. For maintenance therapy, reduce to 0.5 g/kg/day. Administer with a drink or a little jam or honey (not fruit juice).
• Rectal: 0.5-1 g/kg in an appropriate diluent, as a retention enema, followed by colonic irrigation to recover the resin.

Special Cases:

• Elderly Patients: Start with a lower dose and monitor electrolyte levels closely.
• Patients with Renal Impairment: Dosage adjustment based on serum potassium levels and other electrolytes.
• Patients with Hepatic Dysfunction: No specific dosage adjustments are typically required.
• Patients with Comorbid Conditions: Careful monitoring for gastrointestinal complications, especially in patients with bowel disease or compromised motility.

Clinical Use Cases

Dosing recommendations for specific clinical settings generally adhere to the standard dosing guidelines while considering patient factors, such as the severity of hyperkalemia and other electrolyte disturbances. Frequent monitoring of electrolyte levels is crucial in these scenarios.

• Intubation, Surgical Procedures, Mechanical Ventilation, Intensive Care Unit (ICU) Use, Emergency Situations: Dosage adjustments according to the severity of hyperkalemia and the patient’s overall condition. Frequent monitoring of electrolyte levels is crucial.

Dosage Adjustments

• Dose modifications are required based on patient-specific factors, including renal function, presence of other medical conditions, and concurrent medication use. Frequent monitoring of electrolyte levels (potassium, calcium, magnesium) is critical.

Side Effects

Common Side Effects

• Constipation
• Nausea
• Vomiting
• Diarrhea
• Loss of appetite
• Hypomagnesemia
• Hypocalcemia

Rare but Serious Side Effects

• Intestinal necrosis (particularly with sorbitol co-administration)
• Gastrointestinal obstruction
• Colonic perforation
• Fecal impaction

Long-Term Effects

• Chronic hypomagnesemia
• Chronic hypocalcemia

Adverse Drug Reactions (ADR)

• Severe hypokalemia
• Metabolic alkalosis
• Gastrointestinal bleeding

Contraindications

• Hypokalemia
• Hypercalcemia
• Obstructive bowel disease
• Neonates with reduced gut motility (oral administration)
• Hypersensitivity to polystyrene sulfonate resins

Drug Interactions

• Sorbitol: Increases risk of intestinal necrosis. Avoid concomitant use.
• Cation-donating agents (e.g., antacids containing magnesium or aluminum): May reduce the effectiveness of Calcium Polystyrene Sulfonate and may increase the risk of metabolic alkalosis.
• Digitalis glycosides: Toxicity of digitalis may be exacerbated by hypokalemia induced by Calcium Polystyrene Sulfonate.
• Lithium, levothyroxine: Reduced absorption of these drugs may occur when administered concurrently with Calcium Polystyrene Sulfonate.
• Orally administered medications: Calcium Polystyrene Sulfonate can bind to other oral drugs, potentially reducing their absorption and effectiveness. Administer other oral medications at least 3 hours before or after Calcium Polystyrene Sulfonate.

Pregnancy and Breastfeeding

• Pregnancy Safety Category: Limited data available. Not recommended during pregnancy unless the potential benefits outweigh the risks.
• It is unknown whether Calcium Polystyrene Sulfonate metabolites are excreted in human milk. Caution advised during breastfeeding.

Drug Profile Summary

• Mechanism of Action: Exchanges calcium for potassium in the intestine, reducing serum potassium levels.
• Side Effects: Constipation, nausea, vomiting, diarrhea, electrolyte imbalances (hypokalemia, hypomagnesemia, hypocalcemia).
• Contraindications: Hypokalemia, hypercalcemia, obstructive bowel disease, neonates with reduced gut motility (oral use).
• Drug Interactions: Sorbitol, cation-donating agents, digitalis, lithium, levothyroxine.
• Pregnancy & Breastfeeding: Not recommended unless benefits outweigh risks.
• Dosage: See detailed dosage guidelines above.
• Monitoring Parameters: Serum potassium, calcium, magnesium levels; bowel function.

Popular Combinations

Generally not used in combination therapies. Its primary use is as a single agent for managing hyperkalemia.

Precautions

• Monitor electrolyte levels closely throughout treatment.
• Avoid concomitant use of sorbitol.
• Use cautiously in patients with any history of bowel disease or altered motility.
• Do not administer orally to neonates.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Calcium Polystyrene Sulfonate?

A: See detailed dosage guidelines above for adults, children, and special populations.

Q2: How does Calcium Polystyrene Sulfonate work?

A: It exchanges calcium ions for potassium ions in the intestine, primarily in the colon, facilitating potassium excretion and lowering serum potassium levels.

Q3: What are the most common side effects?

A: The most common side effects are constipation, nausea, vomiting, diarrhea, loss of appetite, and electrolyte imbalances (hypomagnesemia, hypocalcemia).

Q4: What are the serious side effects of Calcium Polystyrene Sulfonate?

A: Severe hypokalemia, intestinal necrosis (especially with concomitant sorbitol administration), gastrointestinal obstruction, colonic perforation, and fecal impaction are rare but serious potential side effects.

Q5: Who should not take Calcium Polystyrene Sulfonate?

A: Patients with hypokalemia, hypercalcemia, obstructive bowel disease, and neonates with reduced gut motility (oral administration) should not take this medication.

Q6: Can pregnant or breastfeeding women take Calcium Polystyrene Sulfonate?

A: It is generally not recommended during pregnancy or breastfeeding unless the potential benefits outweigh the risks. Limited data is available regarding its safety in these populations.

Q7: What medications interact with Calcium Polystyrene Sulfonate?

A: Sorbitol, cation-donating agents, digitalis glycosides, lithium, levothyroxine, and other orally administered medications can interact with Calcium Polystyrene Sulfonate.

Q8: How should Calcium Polystyrene Sulfonate be administered?

A: It can be administered orally as a suspension or rectally as a retention enema.

Q9: What should be monitored during Calcium Polystyrene Sulfonate therapy?

A: Serum potassium, calcium, and magnesium levels should be monitored regularly, as well as bowel function.

Q10: What is the onset of action of Calcium Polystyrene Sulfonate?

A: The onset of action can vary but may take several hours to days to achieve a significant reduction in serum potassium levels. It’s essential to monitor serum potassium regularly.