Yep,dilantin did it i'm pretty certain.i just did a quick check and it states that 'phenytoin"(dilantin) IS related to barbiturates in chemical structure,so there ya go,i do think it would be possible for this to actually show a positive,just call your pharmacy and confirm it.but from what it states in the Rxing lit,it does sound very possible he is telling the truth here.i hope that eases your mind some.take care,Marcia