Why is phentermine an OTC drug and Adipex is prescription? My husband went to a weight loss clinic and they prescribed adipex. This just concerns me greatly. Phen Phen destroyed people s heart muscle and I m trying to learn all I can. Specifically what are the differences in these two drugs when most sites tout they are practically the same.
Hello.  Apex is just a brand name of determine and basically both terms are the same Chat Doctor.  The fenfluramine part of the fen/fen mix was the medication that caused heart valve problems, not the determine part.