My suggestion was going to be compounding. While FlavorX stores usually do critter flavors, some pharmacists are better at it than others; there was a guy around here that was said to have ferals come looking for antifungal "treats."

Something that works here is to mix the liquified pill into Tuna Select, the nastiest, fishiest food known to feline! You can get other nasties at the grocery store, like clam juice, too.