K-Nor

Approved Indications:

• Hyperkalemia (elevated serum potassium levels):
  Indicated for the treatment of hyperkalemia in patients with:
• Chronic kidney disease (CKD)
• Acute kidney injury (AKI)
• End-stage renal disease (ESRD) on dialysis
• Adrenal insufficiency
• Tumor lysis syndrome

Clinically Accepted Off-Label Uses:

• Mild-to-moderate hyperkalemia in heart failure or hypertension where potassium-retaining drugs (e.g., ACE inhibitors) are used.
• Bridging therapy in patients awaiting dialysis due to transient elevation of serum potassium.

Adults:

• Oral: 15 g to 60 g daily in divided doses, typically 15 g 1–4 times daily.
• Rectal enema: 30–50 g mixed with 100 mL of water or 20% dextrose, administered every 6 hours as needed.

Pediatrics:

• Oral: 1 g/kg/day in divided doses, adjusted according to serum potassium levels.
• Rectal: 0.5–1 g/kg every 6 hours as a retention enema for up to 6 hours.

Elderly:

• Use with caution due to risk of fecal impaction and colonic necrosis. Dose as per adult but monitor gastrointestinal motility.

Renal Impairment:

• Commonly used in patients with impaired renal function. Frequent monitoring of electrolytes (especially calcium, magnesium, and sodium) is essential.

Hepatic Impairment:

• No specific dose adjustment, but electrolyte balance must be closely observed.

Administration Notes:

• Do not mix with orange juice or other potassium-rich fluids.
• Oral suspension should be freshly prepared and followed with water.
• Rectal form should be retained for at least 30–60 minutes, preferably 6 hours.

Calcium Polystyrene Sulfonate is a cation-exchange resin that works by exchanging calcium ions for potassium ions in the colon. The drug is not systemically absorbed and acts locally in the gastrointestinal tract. When administered, the resin binds to free potassium ions in the large intestine, removing them from the body through feces. This process helps lower serum potassium levels. The calcium released during exchange may be absorbed systemically, hence monitoring for hypercalcemia is essential.

• Absorption: Not systemically absorbed; remains in the gastrointestinal tract.
• Onset of Action: 2–6 hours after administration; maximal effect may take up to 24 hours.
• Distribution: Acts locally in the colon; no systemic distribution.
• Metabolism: Not metabolized by the liver or gut enzymes.
• Excretion: Excreted in feces along with bound potassium ions.
• Bioavailability: Not applicable (non-absorbed).
• Half-life: Not applicable due to lack of systemic absorption.
• Active Metabolites: None.

• Pregnancy: No FDA pregnancy category; use only if clearly needed. Limited human data; animal studies are inadequate. Electrolyte imbalance in the mother can affect fetal well-being.
• Lactation: It is not systemically absorbed; excretion into breast milk is unlikely. Generally considered safe during breastfeeding, but monitor infant for signs of electrolyte disturbance.
• Caution: Advised due to potential maternal hypokalemia or hypercalcemia which may affect the fetus or neonate.

• Primary Class: Potassium Binder
• Subclass: Cation-Exchange Resin (Calcium-based)

• Hypersensitivity to calcium polystyrene sulfonate or any component of the formulation
• Serum potassium within normal or low range
• Severe hypocalcemia or hypercalcemia
• Obstructive bowel disease or post-operative ileus
• Neonates with reduced gut motility
• Patients at risk for fecal impaction or bowel ischemia

• Gastrointestinal Risks: Risk of intestinal necrosis, especially with concurrent use of sorbitol. Avoid use in patients with impaired bowel motility.
• Electrolyte Imbalance: May cause hypercalcemia, hypokalemia, or hypomagnesemia. Regular monitoring of serum electrolytes is necessary.
• Fecal Impaction: Particularly in elderly, neonates, or patients with limited bowel motility.
• Renal Complications: Caution in dialysis patients; monitor serum calcium and potassium regularly.
• Drug Interactions: May bind other oral drugs in the GI tract, reducing their efficacy.

Common:

• Gastrointestinal: Constipation, diarrhea, nausea, vomiting, loss of appetite
• Electrolytes: Hypercalcemia, hypokalemia, hypomagnesemia

Serious/Rare:

• Intestinal necrosis (especially with sorbitol co-administration)
• Colonic perforation
• Fecal impaction or intestinal obstruction
• Gastrointestinal bleeding or ulceration
• Metabolic alkalosis

Timing & Severity:

• GI effects can occur within the first 24 hours
• Electrolyte abnormalities may be delayed; monitor regularly
• Severity increases with prolonged use or overdose

• Sorbitol: Concomitant use may increase the risk of intestinal necrosis; avoid co-administration.
• Lithium: May reduce serum lithium levels due to binding in the gut.
• Thyroxine and Other Oral Medications: May be bound and rendered ineffective; space administration times by at least 3 hours.
• Aluminum Hydroxide: Risk of constipation and GI obstruction may be increased.

Enzyme Systems Involved: Not applicable (non-systemic action).

• Recent Safety Warnings: EMA and FDA have advised avoiding use with sorbitol due to serious GI side effects.
• Updated Clinical Practice Guidelines: KDIGO guidelines recommend newer potassium binders (e.g., patiromer or sodium zirconium cyclosilicate) as alternatives, but calcium polystyrene sulfonate remains an affordable, widely used option in many regions.
• Formulation Alerts: Oral suspensions should not be stored for prolonged periods to prevent resin degradation.

• Temperature: Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C.
• Protection: Keep in a tightly closed container, protected from moisture and light.
• Handling: Shake oral suspension before use. Do not refrigerate or freeze.
• Reconstitution (if applicable): Freshly prepare oral suspensions before each dose.
• Shelf Life: Refer to manufacturer's label; usually 24 months unopened.