The FDA recommends that patients avoid taking sodium polystyrene sulfonate (Kayexalate and generics) at the same time as other oral medications, the agency announced on Sept. 6.
The potassium-lowering drug works by binding with potassium in the intestines so that it can be removed from the body. The FDA's recommendation follows a study finding that sodium polystyrene sulfonate also binds to many common oral medications, which decreases their absorption and effectiveness, according to the news release.
To reduce the likelihood of this occurrence, patients should take oral medicines at least three hours before or three hours after taking sodium polystyrene sulfonate, according to the FDA. Doses should be separated by six hours for patients with gastroparesis or other conditions that result in delayed gastric emptying. The agency will update the drug's labels to include information about dosing separation.