Damned If You Do, Damned If You Don't

Abstract

Sodium polystyrene sulfonate (SPS) potassium binding resins increase colonic potassium excretion and are approved by the U.S. Food and Drug Administration (FDA) for the treatment of hyperkalemia. In 2009, the FDA recommended that sorbitol, a cathartic often given with SPS to prevent obstipation, not be added to SPS powder because of associated colonic necrosis. A premixed oral suspension of SPS in 33% sorbitol was not included in this warning. SPS resins increase stool potassium excretion in normokalemic subjects, but proportionately more potassium is excreted due to cathartics when the two are combined. In hyperkalemic patients, oral SPS mixed in water significantly decreases serum potassium within 24 hours. SPS/sorbitol-associated colonic necrosis is most commonly seen in patients who have received enemas in the setting of recent abdominal surgery, bowel injury, or intestinal dysfunction. It is a rare event, on the order of 0.2 to 0.3%, almost exclusively present in patients at risk. The agent most likely associated with colonic necrosis is 70% sorbitol, and animal data support that etiology. There is very little data to suggest that oral SPS given with 33% sorbitol (in the premixed form) or SPS powder in water orally or as an enema causes colonic necrosis. SPS ion-exchange resins are the only agents, other than dialysis and diuretics, available to increase potassium excretion in hyperkalemia, and when used appropriately, they appear to be clinically effective and reasonably safe.

Association between Serum Potassium and Outcomes in Patients with Reduced Kidney Function

“…For example, diuretics are effective (16) but may be inappropriate for all patients because of volume control: in the present study, ,25% of patients with hyperkalemia at baseline were treated with loop or thiazide diuretics, suggesting that contraindications may exist for many patients. Likewise, sodium polystyrene sulfonate was a mainstay of management (17); however, its efficacy is questionable given the emerging safety concerns with its persistent use (18). Furthermore, our study results indicate that one frequent response to hyperkalemia was discontinuation of RAAS blockers.…”

Effectiveness of Sodium Polystyrene Sulfonate for Short-Term Treatment of Hyperkalemia

“…6,8 A study published in 2009 reported 11 cases of colonic necrosis associated with the use of sorbitol-SPS over the course of 9 years, 4 of which were fatal. 25 In the same year, the FDA posted warnings about the association between sorbitol-containing SPS and potentially fatal intestinal necrosis (bleeding, ischemic colitis, perforation).…”

“…7 SPS is predominantly used for mild hyperkalemia (defined as serum potassium between 5 and 6 mmol/L), where the risk of complications is low. 8 SPS was approved in 1958 by the US Food and Drug Administration (FDA), before drug manufacturers were required to prove that their products were efficacious. 7,9 SPS was approved in Canada 3 years later, in 1961.…”

“…[6][7][8] A systematic review evaluated adverse reactions reported between 1948 and July 2011 using the World Health Organization causality assessment criteria and concluded that gastrointestinal adverse effects may be linked to SPS both with and without sorbitol. 16 Given the lack of strong clinical evidence of effectiveness and the potential for adverse effects, the current study was performed to evaluate the effectiveness of SPS in reducing serum potassium.…”

Potassium Binders in Hemodialysis Patients: A Friend or Foe?

“…Sodium polystyrene sulfonate (Kayexalate) was approved in 1958 by the US FDA, as a potassium-binding resin in the colon, for the management of hyperkalemia. 1 Similarly, calcium resonium or calcium polystyrene sulfonate has been approved for use in Europe. The use of potassiumbinding resins has proven to be of value in the pre-dialysis chronic kidney disease (CKD) setting and in the management of emergency hyperkalemia; however, there is insufficient evidence regarding its efficacy and utility in patients with end-stage renal disease on dialysis.…”