sodium polystyrene sulfonate 250 MG/ML Oral Suspension [Kionex]

INDICATIONS AND USAGE Sodium Polystyrene Sulfonate Powder, for Suspension is indicated for the treatment of hyperkalemia. Limitation of Use: Sodium Polystyrene Sulfonate Powder, for Suspension should not be used as an emergency treatment for life-threatening hyperkalemia because of its delayed onset of action [see Clinical Pharmacology (12.2)] . Sodium Polystyrene Sulfonate Powder, for Suspension is indicated for the treatment of hyperkalemia (1) . Limitation of Use: Sodium Polystyrene Sulfonate Powder, for Suspension should not be used as an emergency treatment for life-threatening hyperkalemia because of its delayed onset of action (1) .

DOSAGE AND ADMINISTRATION Suspension of this drug should be freshly prepared and not stored beyond 24 hours. The average daily adult dose of the resin is 15 g to 60 g. This is best provided by administering 15 g (approximately 4 level teaspoons) of sodium polystyrene sulfonate one to four times daily. One gram of sodium polystyrene sulfonate contains 4.1 mEq of sodium; one level teaspoon contains approximately 3.5 g of sodium polystyrene sulfonate and 15 mEq of sodium. (A heaping teaspoon may contain as much as 10 g to 12 g of sodium polystyrene sulfonate.) Since the in vivo efficiency of sodium-potassium exchange resins is approximately 33 percent, about one third of the resin's actual sodium content is being delivered to the body. In smaller children and infants, lower doses should be employed by using as a guide a rate of 1 mEq of potassium per gram of resin as the basis for calculation. Each dose should be given as a suspension in a small quantity of water or, for greater palatability, in syrup. The amount of fluid usually ranges from 20 mL to 100 mL, depending on the dose, or may be simply determined by allowing 3 mL to 4 mL per gram of resin. Healthcare professionals should follow full aspiration precautions when administering this product, such as placing and maintaining the patient in an upright position while the resin is being administered. The resin may be introduced into the stomach through a plastic tube and, if desired, mixed with a diet appropriate for a patient in renal failure. The resin may also be given, although with less effective results, in an enema consisting (for adults) of 30 g to 50 g every six hours. Each dose is administered as a warm emulsion (at body temperature) in 100 mL of aqueous vehicle. The emulsion should be agitated gently during administration. The enema should be retained as long as possible and followed by a cleansing enema. After an initial cleansing enema, a soft, large size (French 28) rubber tube is inserted into the rectum for a distance of about 20 cm, with the tip well into the sigmoid colon, and taped in place. The resin is then suspended in the appropriate amount of aqueous vehicle at body temperature and introduced by gravity, while the particles are kept in suspension by stirring. The suspension is flushed with 50 mL or 100 mL of fluid, following which the tube is clamped and left in place. If back leakage occurs, the hips are elevated on pillows or a knee-chest position is taken temporarily. A somewhat thicker suspension may be used, but care should be taken that no paste is formed, because the latter has a greatly reduced exchange surface and will be particularly ineffective if deposited in the rectal ampulla. The suspension is kept in the sigmoid colon for several hours, if possible. Then, the colon is irrigated with nonsodium containing solution at body temperature in order to remove the resin. Two quarts of flushing solution may be necessary. The returns are drained constantly through a Y tube connection. While the use of sorbitol is not recommended, particular attention should be paid to this cleansing enema if sorbitol has been used. The intensity and duration of therapy depend upon the severity and resistance of hyperkalemia. Sodium polystyrene sulfonate should not be heated for to do so may alter the exchange properties of the resin.

WARNINGS Intestinal Necrosis Cases of intestinal necrosis, which may be fatal, and other serious gastrointestinal adverse events (bleeding, ischemic colitis, perforation) have been reported in association with sodium polystyrene sulfonate use. The majority of these cases reported the concomitant use of sorbitol. Risk factors for gastrointestinal adverse events were present in many of the cases including prematurity, history of intestinal disease or surgery, hypovolemia, and renal insufficiency and failure. Concomitant administration of additional sorbitol is not recommended (see PRECAUTIONS, Drug Interactions ). • Use only in patients who have normal bowel function. Avoid use in patients who have not had a bowel movement post-surgery. • Avoid use in patients who are at risk for developing constipation or impaction (including those with history of impaction, chronic constipation, inflammatory bowel disease, ischemic colitis, vascular intestinal atherosclerosis, previous bowel resection, or bowel obstruction). • Discontinue use in patients who develop constipation. Alternative Therapy in Severe Hyperkalemia Since the effective lowering of serum potassium with sodium polystyrene sulfonate may take hours to days, treatment with this drug alone may be insufficient to rapidly correct severe hyperkalemia associated with states of rapid tissue breakdown (e.g., burns and renal failure) or hyperkalemia so marked as to constitute a medical emergency. Therefore, other definitive measures, including dialysis, should always be considered and may be imperative. Hypokalemia Serious potassium deficiency can occur from sodium polystyrene sulfonate therapy. The effect must be carefully controlled by frequent serum potassium determinations within each 24 hour period. Since intracellular potassium deficiency is not always reflected by serum potassium levels, the level at which treatment with sodium polystyrene sulfonate should be discontinued must be determined individually for each patient. Important aids in making this determination are the patient's clinical condition and electrocardiogram. Early clinical signs of severe hypokalemia include a pattern of irritable confusion and delayed thought processes. Electrocardiographically, severe hypokalemia is often associated with a lengthened Q-T interval, widening, flattening, or inversion of the T wave, and prominent U waves. Also, cardiac arrhythmias may occur, such as premature atrial, nodal, and ventricular contractions, and supraventricular and ventricular tachycardias. The toxic effects of digitalis are likely to be exaggerated. Marked hypokalemia can also be manifested by severe muscle weakness, at times extending into frank paralysis. Electrolyte Disturbances Like all cation-exchange resins, sodium polystyrene sulfonate is not totally selective (for potassium) in its actions, and small amounts of other cations such as magnesium and calcium can also be lost during treatment. Accordingly, patients receiving sodium polystyrene sulfonate should be monitored for all applicable electrolyte disturbances. Systemic Alkalosis Systemic alkalosis has been reported after cation-exchange resins were administered orally in combination with nonabsorbable cation-donating antacids and laxatives such as magnesium hydroxide and aluminum carbonate. Magnesium hydroxide should not be administered with sodium polystyrene sulfonate. One case of grand mal seizure has been reported in a patient with chronic hypocalcemia of renal failure who was given sodium polystyrene sulfonate with magnesium hydroxide as a laxative (See PRECAUTIONS, Drug Interactions ). Risk of Aspiration Cases of acute bronchitis or bronchopneumonia caused by inhalation of sodium polystyrene sulfonate particles has been reported. Patients with impaired gag reflex, altered level of consciousness, or patients prone to regurgitation may be at increased risk. Administer sodium polystyrene sulfonate suspension with the patient in an upright position. Binding to Other Orally Administered Medications Sodium polystyrene sulfonate suspension may bind orally administered medications, which could decrease their gastrointestinal absorption and lead to reduced efficacy. Administer other oral medications at least 3 hours before or 3 hours after sodium polystyrene sulfonate suspension. Patients with gastroparesis may require a 6 hour separation (see DOSAGE AND ADMINISTRATION and PRECAUTIONS, Drug Interactions ).

CONTRAINDICATIONS Sodium Polystyrene Sulfonate Powder, for Suspension is contraindicated in patients with the following conditions: • Hypersensitivity to polystyrene sulfonate resins • Obstructive bowel disease • Neonates with reduced gut motility • Hypersensitivity to polystyrene sulfonate resins (4) • Obstructive bowel disease (4) • Neonates with reduced gut motility (4)

CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Sodium polystyrene sulfonate is a non-absorbed, cation exchange polymer that contains a sodium counterion. Sodium polystyrene sulfonate increases fecal potassium excretion through binding of potassium in the lumen of the gastrointestinal tract. Binding of potassium reduces the concentration of free potassium in the gastrointestinal lumen, resulting in a reduction of serum potassium levels. The practical exchange ratio is 1 mEq K per 1 gram of resin. As the resin passes along the intestine or is retained in the colon after administration by enema, the sodium ions are partially released and are replaced by potassium ions. This action occurs primarily in the large intestine, which excretes potassium ions to a greater degree than does the small intestine. The efficiency of this process is limited and unpredictably variable. 12.2 Pharmacodynamics The effective lowering of serum potassium with sodium polystyrene sulfonate may take hours to days. 12.3 Pharmacokinetics The in vivo efficiency of sodium-potassium exchange resins is approximately 33 percent; hence, about one third of the resin's actual sodium content is delivered to the body. Sodium polystyrene sulfonate is not absorbed systemically. Drug Interactions In vitro binding studies showed that sodium polystyrene sulfonate bound significantly to the following tested drugs – warfarin, metoprolol, phenytoin, furosemide, amlodipine and amoxicillin.