yes if your on methadone they tell you not to take ANY benzodiazepines because they can react badly with the methadone and give you a seizure... That may not be true Methadone clinics hate the extra...
Yes, ephedra can show up as an amphetamine...and meth can take 3-5 days to clean out with a lot of water...I would probably pray for 10 days to be clean.