Hi. I'm Dr. Gotthelf. I have been a vet for 35 years and I would like to use my experience to help you with your pet's medical problem.
When cats have IBD, their colon protrudes into the stomach and decreases their appetite. So I usually recommend liquifying and warming the food to entice the cat to eat. If she cannot eat, then she may need to be tube fed to provide nutrition. Often I will also use a drug called mirtazapine (3.5mg twice weekly) to stimulate a cat's appetite.
She had been on Mirtazapine once before and it helped a bit. But she had an appetite at that time. I have been feeding her with a syringe as much as 4-5 tablespoons a day. She has not vomited once. I feel that something more is going on with her. I also read that Lukeran can cause gastrointestinal upset. I feel that more should be explored before any vet thinks of putting my cat to sleep. She still goes outside and cleans herself. I can tell she's in a lot of discomfort because last night she came into the air conditioned living room for the first time all day and she was turning from one side to the other. She has been spending most of her time in the bathroom because that is the coolest room in the house.
I have been giving her about 9 tablespoons of food a day and she is not getting better. She is very weak. The meds are not working although she has not been vomiting. She has been prescribed Mirtazapine one quarter tablet every day (3.75 mg). I don't have much hope at this point. Now my vet thinks that maybe she had lymphoma all along and could be in her final stages. It's very sad. I can't think of anything else to do.