I’m having the same problem — it began Oct 5.
Phentermine is listed in my Moderation list, and just to be sure, I entered it in all caps (as this spammer does). I made certain it’s spelled the same way, too).
I’ve got the most recent versions of Askimet and I’ve got SK2, and all of a sudden I keep getting hit with with spam with the word PHENTERMINE in the URL.
It’s as if the moderation thingy doesn’t work anymore. These spams are also getting past SK2 and Askimet, so there’s something different about them. I upped my SK2 settings so everything is Kinda Mean, but that didn’t help, either. I finally turned off the comments for the one post that kept getting hit.
But I’m wondering how “Phentermine” is getting past the WordPress moderation list in the first place. It used to catch stuff like this.