Does phentermine show up in a regular drug test?

The short answer is no, it will not show up in a drug test. The longer answer is that its metabolite, norphentermine, may very well be detected in a urine drug test. Phentermine works by stimulating nerve cells in your brain to release more norepinephrine (also known as adrenaline). Normally when you’re hungry, your brain sends out norepinephrine to signal your body to eat. It also suppresses your appetite after you’ve eaten enough food. So when you take phentermine—and especially with an empty stomach—the medication stimulates nerve cells even more than usual and can increase adrenaline levels significantly.Phentermine (Adipex-P) is the most prescribed medication for weight loss in the United States. Taking phentermine may occasionally result in a false positive urine test for amphetamines in that case our weight loss doctor will write a letter to your employer on your behalf.