If someone is prescribed methadone, will it be possible to tell if they use heroin by doing a drug test? YES! I work at a Pain Care Physician and we drug test our pt that we are prescribing medication to ALL THE TIME! Methadone is a pain medication and is only given to heroine addicts to cover up withdraw symptoms its not actually a form of heroine! Yes, they are two different drugs with different chemical compositions. If you are taking methadone, a drug test will NOT show you're taking heroin. if they run a spec they can differentiate. if they just use an assay (dipstick) then it will just be positive for opiates-doesn't differentiate which type. of course a positive assay test results in a confirmation via mass spectrometer. | 