title: Damned if you do, damned if you don't: potassium binding resins in hyperkalemia.
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.
authors.forename: Maura
authors.initials: M
authors.lastname: Watson
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Abbott
authors.forename: Christina M
authors.initials: CM
authors.lastname: Yuan
mesh_terms: D000818:Animals; D002400:Cathartics / Q000009:adverse effects / Q000627:therapeutic use*; D002411:Cation Exchange Resins / Q000009:adverse effects / Q000627:therapeutic use*; D003106:Colon / Q000187:drug effects / Q000473:pathology; D004338:Drug Combinations; D004357:Drug Synergism; D019317:Evidence-Based Medicine; D005243:Feces / Q000737:chemistry; D006801:Humans; D006947:Hyperkalemia / Q000097:blood / Q000188:drug therapy*; D009336:Necrosis; D011137:Polystyrenes / Q000009:adverse effects / Q000627:therapeutic use*; D011188:Potassium / Q000097:blood*; D017410:Practice Guidelines as Topic; D018570:Risk Assessment; D013012:Sorbitol / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome; D014481:United States; D014486:United States Food and Drug Administration
chemical_list: D002400:Cathartics; D002411:Cation Exchange Resins; D004338:Drug Combinations; D011137:Polystyrenes; D013012:Sorbitol; C003321:polystyrene sulfonic acid; D011188:Potassium