The short answer is no, it will not show up in a drug test. Therefore, phentermine can (although not always) show up on standard drug tests of all types as amphetamines. Therefore even if you have taken phentermine recently there may still be no trace of it left in your system by the time you take the test depending on how quickly your body metabolizes it. If you take a blood test, it may be detectable for up to 24 hours. If you have insurance that covers Adipex, for example, it may be cheaper to simply use your insurance rather than paying out of pocket with a GoodRx coupon. One of the most common symptoms of Adipex withdrawal is fatigue and lethargy. Adipex Rx should not be taken by individuals who are allergic to Phentermine or any of its ingredients. A rare, frequently fatal disease of the lungs-has been reported to occur in patients receiving a combination of phentermine with fenfluramine or dexfenfluramine. Drink plenty of water each day to prevent dehydration or kidney stones while you are taking phentermine and topiramate. As phentermine causes your brain to release large amounts of dopamine and serotonin, it's possible to become addicted to this pleasurable sensation. What are the risks of phentermine?