The Food and Drug Administration (FDA) announced that it will require the manufacturer of Kayexalate (sodium polystyrene sulfonate; Concordia Pharmaceuticals) to conduct studies on drug-drug interactions that may reduce the efficacy of co-administered medications when taken with Kayexalate.
The approved labeling for Kayexalate includes its potential to decrease absorption of lithium and thyroxine but extensive drug-drug interaction studies have not been conducted. The FDA is requiring Concordia Pharmaceuticals to conduct studies on drug-drug interactions after another drug with the same indication (Veltassa) bound to half of the medications tested and decreased the efficacy of these medications. The recently approved Veltassa contains a Boxed Warning recommending that other oral medications should be administered at least 6 hours before or after taking Veltassa.
If these studies confirm significant drug-drug interactions, the FDA will require all manufacturers of sodium polystyrene sulfonate products to update the drug labels to include information about these interactions.
To reduce this potential risk, prescribers and patients should consider separating Kayexalate dosing from other medications taken by mouth by at least 6 hours. This includes both prescription medications, such as antibiotics, antihypertensive agents and blood thinners, and those purchased over-the-counter without a prescription, such as antacids and laxatives. Healthcare professionals should monitor blood levels or clinical response to the other medications when appropriate.
Kayexalate and its generic versions are indicated for the treatment of hyperkalemia.
For more information call (888) 463-6332 or visit FDA.gov.