Hyperphosphatemia is a condition in which the level of phosphorus in the blood is elevated that is very common with chronic kidney disease in cats.  High levels of phosphorus cause calcium loss from the bones, which in turn, causes the bones to become soft and weak, known as a condition called “rubber jaw”. In addition, a high phosphorus level causes further kidney damage due to calcification of the kidneys.  Diagnosing hyperphosphatemia requires a blood draw to measure the phosphorus level. Treating hyperphosphatemia involves correcting the phosphorus level through diet and/or medication.  Feeding a low phosphorus diet can lower the phosphorus that your cat obtains from food. Dr. Lisa Pierson has generated a list (see the link below) of the phosphorus content in canned foods. Traditional prescription kidney diets contain less phosphorus, but are controversial due to their lack of protein. 

Medications that can help lower the phosphorus level are Epakitin and Aluminum hydroxide.  Both of these medications are used to bind the phosphorus that is in the gastrointestinal tract.  The daily dosage must be divided and given each time the cat is fed to be effective.  It is important not to overdose these medications.

Phosphorus binders can be ordered through us at:



List of phosphorus levels of various diets: