He had the surgery Wednesday last week but had to go back again on Saturday as he wee tickle (sorry only way I can politely describe it

) had been so of not going back in if you know what I mean? It was starting to get infected so I had to get another wee stitch into it to keep it in. The vets gave him Tramodol Melt 50mg Zamodol and I have to give him a quarter of the tablet twice daily.
It only occurred to him that is has only been happening since he got home from the vet on Saturday and I tried to think what has happened differently since, other than the homecooked diet his is on, he has been taking the Tramodol so I am wondering if it is a reaction to it.
I have searched on the internet and respiratory depression is a side effect and also I did see coughing on another site I read. So I ran the vet this morning but they are in open surgery now and have to wait to 11am to speak to them. Just hoping this is the case and that when he is off them he will go back to normal with no permanent effects.