Even the WeightWatchers community chat website had more than 80 message-board entries in which users talked about using phentermine - also commonly sold online under the brand names Duromine, Ionamine, side effects from the drug Adipex and Fastin. side effects from the drug Adipex diet drug with Phentermine HCl, should not be mistaken as a substitute for food. Use this weight loss medication under proper medical supervision, as it is habit-forming drug and can make you physically and psychologically reliant.