My son failed a drug test for methamphetamines and amphetamines. Can over the counter drugs cause th

Actually ephedrine and diphenhydramine can sometimes cause an amphetamine test to be positive but either way that's really not good for your son and you should talk to him about it in a casual way/don't force him to stop because as a child that always wanted to make me do it more
Hope this helps

No sir if you are not giving him these medications he is getting them on his own either by friends that have adhd/add or off the street. Some medications that contain this drug are adderall,concerta,ridlan,and vyvanse. Maybe you should talk to some of his friends parents and see if one of his friends takes medication for adhd/add control.