What Is the Role of SPS for Hyperkalemia in CKD?

Nancy H. Hope, PharmD

Disclosures

April 12, 2012

Question:

What is the role of sodium polystyrene sulfonate for hyperkalemia secondary to chronic kidney disease?

Response from Nancy H. Hope, PharmD
Assistant Professor of Pharmacy Practice, Presbyterian College School of Pharmacy, Clinton, South Carolina

Hyperkalemia is a common complication in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Management of hyperkalemia is dependent upon the extent of potassium increase and associated patient symptoms.

Sodium polystyrene sulfonate (SPS) (Kayexalate®) is a cation exchange resin that trades sodium ions for potassium ions, mostly in the large intestine, to enhance the fecal elimination of excess potassium. SPS typically is used in combination with a cathartic agent to enhance fecal elimination of potassium as well as to prevent constipation that can be caused by SPS therapy; however, the concomitant use of SPS and sorbitol increases the risk for gastrointestinal injuries.[1] It is estimated that every gram of SPS binds and excretes about 0.66 mEq of potassium; in the absence of diarrhea (ie, use of SPS without cathartic agent), 1 g of SPS binds and excretes about 1 mEq of potassium.[2]

In asymptomatic CKD patients with mild hyperkalemia, chronic administration of SPS could be useful in preventing further serum potassium elevations. SPS has been shown to be ineffective when given as a single dose. Therefore, it is administered once daily to 4 times daily by mouth or per rectum in patients with CKD for about a week for optimal potassium elimination.[3] SPS is not used for acute management of hyperkalemia because it causes slow elimination of total body potassium over hours to days, resulting in a slower onset of action.[2] As patients progress to higher stages of CKD, the only definitive therapy for hyperkalemia is dialysis.[4]

Actual mortality and outcomes data for the use of SPS therapy in patients with CKD and ESRD have not been established. Its use is also limited secondary to the poor tolerability and documented complications of therapy. Postmarketing surveillance has shown SPS use to be associated with ischemic colitis, gastrointestinal tract ulcerations and necrosis, and intestinal perforation. One of the risk factors listed for development of these complications is renal insufficiency and failure.[1]It is necessary to weigh all risks and benefits prior to beginning SPS therapy in CKD patients.

The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI™) guidelines provide a strong recommendation for the use of SPS to prevent or to treat hyperkalemia after initiation or dose increase of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers.[5]This recommendation, along with all previously mentioned statements above regarding SPS use in CKD and ESRD, is for the management of mild to moderate elevations in serum potassium concentrations in asymptomatic patients.[5]

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