What would cause a negative drug screen while I was taking Adipex? I had been taking Adipex for a month like my doctor had prescribed. When I went into my appointment I had a drug screen and it came back NEGATIVE, I don't understand how this is possible since I was taking the medication? Needless to say, my doctor stopped my prescription for Adipex. Because she said it was not in my urine. I am so frusterated & upset because I was taking the medication like I was told & I was getting great results of weight loss. Please help me understand why I would get a negative urinalysis drug screen if I was taking Adipex?