Welcome to the FDA Drug Safety Podcast for health care professionals from the Division of Drug Information. This is Lesley Navin Advanced Practice Nurse.
On September 6, 2017 FDA recommended that patients avoid taking the potassium-lowering drug sodium polystyrene sulfonate (brand name Kayexalate) at the same time as any other medicines taken by mouth. A study found that sodium polystyrene sulfonate binds to many commonly prescribed oral medicines, decreasing the absorption and therefore the effectiveness of those oral medicines. To reduce this likelihood, we recommend separating the dosing of sodium polystyrene sulfonate from other orally administered medicines by at least 3 hours. We are updating the sodium polystyrene sulfonate drug labels to include information about this dosing separation.
Sodium polystyrene sulfonate is used to treat hyperkalemia, and works by binding with potassium in the intestines so it can be removed from the body. Too much potassium in the blood can cause heart rhythm problems, which in rare cases can be fatal. Sodium polystyrene sulfonate is available as the brand name Kayexalate, as generic brands, and also as non-branded generics.
Health care professionals should advise patients to separate dosing from other orally administered medicines by at least 3 hours. That time should be increased to 6 hours for patients with gastroparesis or other conditions resulting in delayed emptying of food from the stomach into the small intestine.
An in vitro study was conducted to evaluate the binding potential for six orally administered medicines commonly taken together with sodium polystyrene sulfonate - amlodipine, metoprolol, amoxicillin, furosemide, phenytoin, and warfarin. The study found significant binding to sodium polystyrene sulfonate occurred with all of these medicines.
We conclude that sodium polystyrene sulfonate would also be likely to bind to many other oral medicines, and recommend separating its dosing from other oral medications by 3 hours, or 6 hours if the patient has gastroparesis. We have determined that additional drug interaction studies are no longer needed and will release the manufacturer of Kayexalate, Concordia Pharmaceuticals, Inc., from the requirement to conduct further studies. We are adding this new information to the sodium polystyrene sulfonate drug labels.
Side effects involving sodium polystyrene sulfonate should be reported to FDA’s MedWatch program at www.fda.gov/medwatch.
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- FDA Drug Safety Communication: FDA recommends separating dosing of potassium-lowering drug sodium polystyrene sulfonate (Kayexalate) from all other oral drugs
- FDA Drug Safety Podcast: FDA recommends separating dosing of potassium-lowering drug sodium polystyrene sulfonate (Kayexalate) from all other oral drugs