I don't know how many responses you'll get about this one. I think that the Atkins/Low Carb way of eating is all about getting there without the drugs. It's a way of life that has great results all by itself. Did you read Dr Atkins' New Diet Revolution
? Were you following Induction to the letter
? I only ask this because if you're not really following the diet as described in his book, then you may have been putting things into your plan that may have hindered you. I don't know anything about Phentermine, and when I Googled it, I got some hits (through the spam) about it being addicting and almost like an amphetamine in the way it effects your body... So, I'd be careful about taking it, I guess.
I don't know how much you have to lose, but I'm sure JersyGrl will chime in here. She lost over 100 pounds on Atkins, and I'm fairly sure she just did it by the book--no surgery, no drugs, just good eating and exercise. But I'll let her speak for herself
I'm not sure if you've ever read Jimmy Moore's story (he does a radio show and has a blog called "Livin' La Vida Low Carb"), but he lost 180 pounds on Atkins in a year--without phentermine. Just some food for thought.