My cat won't eat urinary S/O after puking. Can I mix old food?

If he was prescribed SO food due to urinary crystals or stones that needs to be the only thing he eats. Any other food can predispose him to another bout of urinary inflammation or crystals. Feeding other food defeats the purpose of the Rx diet. The vomit may be from stress, different food, eating something he shouldn't have or some other underlying disease. If he continues to vomit I would make a veterinary appointment to get him checked out. Make sure that he is still urinating normally, that it's not urinary issues flaring up.

When was Marshmallow put on Urinary SO? If he was just put on the food and he wasn't gradually transitioned to it they can get an upset stomach from it. If this is the case I would call your veterinarian for a bland diet and potentially an antacid to help settle his stomach then do a gradual transition to the new food. If Marshmallow has been on the food for some time, it is less likely the food and more likely something else is going on with Marshmallow. If this is the case I would recommend a visit with your veterinarian and potentially some X-rays making sure there is not foreign body obstruction and some blood work looking for pancreatitis. Your veterinarian can also give him medication to help stop the vomiting and settle his stomach. If you are uncomfortable with the food that they put him on there are other prescription diets for cats you can always ask your veterinarian which other ones they recommend. Thank you for using Petco Pet Education Center, formerly Petcoach.

Hill's non-prescription food is safe, and it's a highly recommend food by vets. There is absolutely no scientific research saying it isn't safe, everything you are reading is anecdotal with no evidence to back it up. It's important that your cat stays on a urinary diet to keep him from getting stones again, so I'd recommend giving him Royal Canin cat urinary SO. It's a high quality food, and he may like eating it. I would have him checked out by a vet about this weight loss, however. In old cats, the weight loss could be due to a medical illness, such as hyperthyroidism, kidney disease, diabetes, or even cancer. He could also have teeth problems making it painful for him to eat. He could not be feeling well from those, causing him to not eat, so it may not be the food, it could be an illness. I recommend having a physical exam, geriatric blood panel, and urinalysis to check his teeth and to see how his organs are functioning to determine if there is a medical cause behind this weight loss and anorexia. Should one be found, the vet can treat him for it. I would have him seen by a vet today or tomorrow.

You may want to try mixing a little bit of his old food in with the new food to gradually transition him to the new food. If he still doesn’t want to eat it you could ask your vet if there are any other foods to try for his condition.

The Royal Canin SO food should not cause lethargy and should be safe to feed to a healthy cat. Lethargy is a somewhat vague sign - it’s possible that this is simply behavioral and not emergent but Otis could also have a fever, he may have ingested something, or it could be any number of other problems. Ultimately you know him best and you should go with your gut - if you’re worried his lethargy seems extreme or if he begins to show other signs like trouble breathing or vomiting I’d recommend making the drive to the vet.

You can try warming it up or mixing in a tiny bit of plain baby food. Since Gabby does have a history of urinary obstructions, discuss surgical options with your veterinarian. A perineal urethrostomy (PU) can be performed to widen the opening through which he urinates to prevent blocking.

I would not recommend doing this. My concern is that if you substitute food then the urinary food isn't doing anything since he is also getting something else and he may become blocked again. I would monitor his weight and how much food you are feeding him instead. Thank you for using Petco Pet Education Center, formerly Petcoach.