Hmmm.... now that seems to be an awfully heavy dose of Panacur to me, particularly for a leo? Did a vet prescribe this to you? I usually dose with it once and repeat 10 to 14 days later. Anywho, the good thing about Panacur is that you can't really overdose with that medication, so you should be ok.
I find that Panacur is an appetite suppressant, so your leo may not feel like eating for a day or two, but his appetite should come back shortly. Again with 3 straight doses of Panacur like you've done, it doesn't surprise me that he won't eat.
As for positive results, you won't see them until the final doses are given in 3 weeks. He should eat in the meantime, but expect him to be off his again after the final meds are given.
Hope this helps.
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