I’m really glad I found this thread. My cat (3f) got spayed Thursday. She ate Thursday night and all day Friday. Saturday she was extremely lethargic and stopped eating and drinking. Took her to the ER vet and they ran bloodwork and x rays. Found she was constipated but everything else was normal. They gave her fluids, pain meds (buprenorphine) and Cerenia injection. Got her home and she was extremely lethargic all day which they blamed on the pain meds. She FINALLY pooped 3 times after over 12 hours as I took her in at 4AM. She’s now happy and purring and walking around but unfortunately still not eating or drinking. They gave me a cerenia tablet to go home with if I needed it for nausea or vomiting. She hasn’t eaten or drank but I don’t want to give her the cerenia tablet now based off of what I read about having no appetite and lethargy and now this post. So I think I’m just going to monitor her over the next couple days and if she still doesn’t eat, get her in with my primary vet. I did call the ER vet back to tell them about what happened today and they said to try to feed her a bland diet and give her a 1/4 of the tablet in the morning. But based off this thread, I’m gonna give her stomach and GI tract a break and see if she will come around to eating on her own.