Can you guess why I'm no longer interested?
What changed is the flavor of the medicine. Before, my Tramadol was blueberry-flavored, which I was a big fan of. However, they then switched to banana-flavored Tramadol for the refill, which I don't really care for at all! (Yes, I know I liked actual bananas. But banana flavoring is not the same!)
You see, there's a difference between mass-produced drugs made by manufacturers, and pharmaceutical compounding, where personalized medicines are prepared for patients using the specific ingredients and dosages needed. One way that compounded medicines can be customized is with flavoring; different animals like different flavors, and if you get it wrong, we won't want to take our medicine.
So if your piggy ever turns their nose up at their medicine, give it a sniff to figure out what flavor it is, and consider asking for another one on your next refill. I'm rather partial to blueberry myself!