Ah, right. Drug interactions, blech. I don't think you're nuts at all -- heck, I kept Murphy through his first few years, when he was an absolute terror with biting and scratching and attacking. Different people are, well, different, when it comes to their cats. And some cats are a bit different. As much as I hate to say this, Murphy is my baby, and while I love Denali, she's much more "just a cat" than he is.