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, USP 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 sorbitol is not recommended (see , ). Intestinal Necrosis:PRECAUTIONSDrug 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 effective lowering of serum potassium with Sodium Polystyrene Sulfonate, USP 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 therapy with Sodium Polystyrene Sulfonate, USP. 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, USP 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, USP 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, USP 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, USP. One case of grand mal seizure has been reported in a patient with chronic hypocalcemia of renal failure who was given Sodium Polystyrene Sulfonate, USP with magnesium hydroxide as laxative. (See , .) PRECAUTIONSDrug Interactions