Polystyrene sulfonate (Kayexalate) is used in renal failure to:
A.
Reduce serum phosphate levels.
B.
Prevent constipation from sorbitol use.
C.
acts by pulling potassium into the bowels and exchanging it for sodium
D.
acts by adding potassium into the bowels and exchanging it for sodium bicarbonate
The correct answer and Explanation is :
The correct answer is C. acts by pulling potassium into the bowels and exchanging it for sodium.
Polystyrene sulfonate, commonly known as Kayexalate, is a cation-exchange resin used primarily to treat hyperkalemia, which is a condition characterized by elevated levels of potassium in the blood. This medication is particularly relevant in patients with renal failure, where the kidneys are unable to effectively excrete potassium, leading to dangerous levels.
Mechanism of Action:
Kayexalate works by exchanging potassium ions for sodium ions in the gastrointestinal tract. When the resin is administered, it binds to potassium in the intestinal lumen. This exchange process effectively removes potassium from the bloodstream and allows it to be excreted through the feces. The sodium ions that replace the potassium ions are absorbed into the body, which can help in maintaining sodium levels but can also lead to an increase in sodium retention, especially in patients with underlying heart conditions or those on sodium-restricted diets.
Clinical Considerations:
While Kayexalate is effective in managing hyperkalemia, its use comes with considerations. The onset of action can take hours to days, making it less suitable for acute hyperkalemic emergencies, where intravenous calcium, insulin, or beta-agonists may be used for rapid potassium reduction. Additionally, the use of Kayexalate can be associated with gastrointestinal side effects, including constipation or diarrhea, and it may also lead to electrolyte imbalances if used excessively.
In summary, Kayexalate is a valuable treatment option in renal failure for managing high potassium levels through its mechanism of exchanging potassium for sodium in the intestines, thus promoting potassium excretion.