You should not abruptly stop the medication. You would want to give a half dose of DIA-IONX on the canned food twice daily on the breakfast and supper food. But you should give it away from the medication. You will need to monitor the blood glucose levels so you can ask your veterinarian about adjusting the Glipizide dose. Other things that are helpful for the diabetic cat is to avoid any dry food since it puts too much on the stress. It is also helpful to give probiotics and OMEGA 3,6,9 to improve digestion and reduce inflammation. If you have chlorinated water it is important to avoid chlorine and give filtered water instead. Please let us know if you have any other questions.