Taking amphetamine (i.e. Adderall, Dexedrine, Vyvanse), bupropion (WellButrin
), dexfenfluramine, fenfluramine, furazolidone, guanadrel, guanethidine, or have taken a monoamine oxidase inhibitor (MAOI) (e.g., phenelzine) in the last 14 days"
This quote is from - http://en.wikipedia.org/wiki/Phentermine
You probably should read the link. I kind of get the feeling that the two meds should not be combined. Hope this helps.