You know me, Jean and Charcoal (GA), since I have posted a lot lately about my Ketchie.
Same thing happened with her, and since the Mirtazapine from the vet's did not seem to be helping her appetite they tried the Cyproheptadine, and my poor Ketchie was totally out of it. Even falling over and she fell off of my bathroom counter a week and a half ago. So, I stopped it altogether and went back to the Mirtazapine.
Thing is, if you use Mirtazapine, make sure it is made my Mylan, a round deep yellow pill, 15 mg. and ask your vet about calling in a prescription to your pharmacist. That worked way better than the generic stuff my vet is using. I might try that yet with Ketchie, even though I know she is on her last leg, but she had that dental last week on Friday, and if I could get some of the original Mirtazapine to try, she might eat some, and at least last a little longer.
Oh, by the way, the Mirtazapine pills are 15 mg. and the vet had on the directions for Gracie (Ketchie's mother), to use a quarter of one of those tablets once every 72 hours. Fortunately, I tried only a sliver of the Mylan brand pill with Ketchie, and within an hour she was eating a lot.
Otherwise, I agree with Larry about giving her a smaller dose and see how that works, of the Cyproheptadine.
Take care!
Jean and Charcoal (GA)