How to choose PHOSPHATE binder for CKD patients

As a clinical pharmacist, you should know how to choose a phosphate binder for patients with chronic kidney disease. These have similar efficacy for lowering phosphate levels, but vary in adverse effects, cost, and pill burden. Aluminum hydroxide isn't used chronically anymore. Aluminum accumulates and leads to bone disease, dementia, and death.

Recommend starting with a calcium-containing product if the patient can tolerate it. Calcium carbonate (Clacimate, etc) is inexpensive, but usually requires a lot of tablets and can cause hypercalcemia. Calcium acetate (Marcal, etc) is slightly more expensive and causes less hypercalcemia, but the number of pills required is large and some patients don't tolerate the GI upset. If the patient can't take a calcium product, recommend Fosrenol or Renagel, these don't cause hypercalcemia, but they cost more. Fosrenol (lanthanum carbonate - NOT available in Egypt) can cause GI upset, plus some patients don't like the chewable tablets. Renagel (sevelamer HCl) can cause constipation. Advise patients to use laxatives or stool softeners to avoid impaction.

Renvela (sevelamer carbonate - NOT available in Egypt) is a new formulation of Renagel. The carbonate salt is an acid buffer, the hydrochloride is not. Therefore Renvela might help reduce the risk of acidosis, but explain that precautions are still needed to prevent constipation. Both work equally well to bind phosphate in the gut, and will cost about the same. Watch for potential mix-ups with Renagel and Renvela, the names are very similar and the dosing is the same. Tell patients to take phosphate binders with their first bites of a meal or snack, they don't work as well if taken after food. Get our note, "Be familiar with how to use phosphate binders", for more information.

REFERENCES

• Delmez J, Block G, Robertson J, Chasan-Taber S, Blair A, Dillon M, Bleyer AJ. A randomized, double-blind, crossover design study of sevelamer hydrochloride and sevelamer carbonate in patients on hemodialysis. Clin Nephrol. 2007 Dec;68(6):386-91. Available at: https://www.dustri.com/article_response_page.html?artId=1050&doi=10.5414/CNP68386&L=0

  Stormont R, McCoy B, Bashir K (2016). New Pharmacotherapy Options for Hyperphosphatemia.US Pharm. 2016;41(3):HS18-HS. Available at: https://www.uspharmacist.com/article/new-pharmacotherapy-options-for-hyperphosphatemia

  Magee J, Robles M, Dunaway P. Sevelamer-Induced Gastrointestinal Injury Presenting as Gastroenteritis. Case Rep Gastroenterol. 2018 Feb 1;12(1):41-45. Available at: https://karger.com/crg/article/12/1/41/87527/Sevelamer-Induced-Gastrointestinal-Injury

  Goyal R, Jialal I. Hyperphosphatemia. [Updated 2022 Jun 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551586