What Is Sodium Polystyrene Sulfonate?
Sodium polystyrene sulfonate is a cation-exchange resin used primarily to treat hyperkalemia by exchanging sodium ions for potassium ions in the body. This yellowish-brown powder is odorless and tasteless, and it is virtually insoluble in water, ethanol, acetone, and diethyl ether.
Uses of Sodium Polystyrene Sulfonate
This resin is indicated for hyperkalemia associated with acute and chronic renal failure. It can be administered orally or rectally, not intravenously as previously mentioned. The oral dose is typically 15 to 30 g, mixed with 20 to 100 mL of water or syrup (without sorbitol), administered one to four times a day. The rectal administration involves a similar dose suspended in a small volume of water or 2% methylcellulose solution, used particularly when oral administration is not feasible.
Properties of Sodium Polystyrene Sulfonate
As a cation-exchange resin, sodium polystyrene sulfonate operates by binding potassium ions in the colon, facilitating their removal from the body through feces. This action helps reduce high potassium levels in the blood. However, it’s associated with potential side effects such as heart failure (due to increased serum sodium), gastrointestinal complications like perforation, ulcers, and necrosis (particularly with sorbitol use), and more common side effects including edema, hypocalcemia, and gastrointestinal discomfort.
Other Information on Sodium Polystyrene Sulfonate
1. Precautions for Concomitant Use
Caution is advised when used with digitalis preparations due to the risk of digitalis toxicity from lowered serum potassium levels. Antacids or laxatives containing aluminum, magnesium, or calcium, and thyroid hormones can interfere with the action of sodium polystyrene sulfonate, reducing its effectiveness or affecting thyroid hormone absorption, respectively.
2. Precautions for Use
Monitoring of serum potassium and sodium levels is essential during treatment. The risk of gastrointestinal complications underscores the importance of avoiding sorbitol-containing solutions and addressing constipation proactively. Special consideration is required when administering to pregnant or nursing women, and elderly patients may need dose adjustments due to potential physiological function impairment.
3. Difference From Calcium Polystyrene Sulfonate
While both sodium and calcium polystyrene sulfonates treat hyperkalemia, sodium variants offer a higher potassium exchange capacity, making them more effective in reducing serum potassium levels. However, calcium polystyrene sulfonate may be preferred in patients with sodium retention issues, despite its potential side effects like constipation and the risk of hypercalcemia-related complications.