Were you able to see my reply above? I'll post it below.
I am very concerned that he may not make it to an appointment that comes next week. When cats stop eating and getting the appropriate amount of calories each day, they are at risk of hepatic lipidosis and liver failure. This can happen as early as 3 days following the onset of food refusal.
I can give you some steps to try at home, but I would recommend taking him to a vet that can see him sooner or being seen at the ER overnight.
The first step is to administer a dose of regular pepcid (famotidine) every 12-24 hours. You will want to give 0.5mg/pound of body weight (a 10# ***** would receive 5mg, a 5# ***** would receive 2.5mg, etc). For this, you can visit any human pharmacy and buy the OTC brand name Pepcid, or you can use the cheaper, off-brand “famotidine” that’s available. Either will be useful.
2 hours following a dose of famotidine, the time needed for the medication to begin working, you can offer pureed baby food in chicken, turkey and similar flavors. Avoid those that contain onion or garlic in the ingredient panel. If he holds this down, work on switching to canned food. Try to give small amounts frequently and work your way up to him eating more.
I’ll be standing by if you have other questions. Let me know if I can help further.
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