Hyperkalemia Treatment May Require New Dosing Instructions

The FDA is requiring Concordia Pharmaceuticals to conduct studies on its hyperkalemia treatment, sodium polystyrene sulfonate (Kayexalate), to see if it binds to other medications administered by mouth, which would decrease potency.

Kayexalate treats hyperkalemia by binding potassium in the large intestine so it can be removed from the body, the FDA noted.

This new look into Kayexalate was spurred by an FDA review of another potassium-lowering drug called Veltassa.

“We found that Veltassa bound to about half of the medications tested, some of which are commonly used in patients who require potassium-lowering drugs,” the FDA wrote in a press release. “Such binding could decrease the effects of these medications.”

Veltassa’s label states that patients should not take other oral medications within 6 hours of taking Veltassa.

Meanwhile, drug-drug interactions studies of Kayexalate have not been performed, which is why the FDA wants Concordia to investigate whether the drug has similar, significant interactions with other medications.

If they do exist, the “FDA will require all manufacturers of sodium polystyrene sulfonate products to update the drug labels to include information about these drug interactions.”

In the meantime, the FDA stated that prescribers and patients should consider separating Kayexalate’s dosing from other medication taken by mouth by at least 6 hours. This would include prescription drugs, such as antibiotics, blood thinners, blood-pressure-lowering agents, and OTC products such as antacids and laxatives.

The FDA also recommended health care professionals monitor blood levels or clinical response to other medications.

The drug’s adverse effects include vomiting, diarrhea, nausea, and upset stomach.