Hi Kate, as I understand it, the thyroid food has to be the sole food for it to work effectively, and I don't know if it can be used as well as thyroid medication, you'd have to check with your vet. There are plenty of renal foods, I would buy them online, as despite being prescription food, you don't need a prescription. Sometimes just changing the dry food and leaving the wet normal can be enough to bring renal values down, but don't be surprised if they go up as her thyroid is stabilised, the extra blood pressure from hyper-t can mask kidney issues.