Today I learned Benadryl can throw a false positive for methadone. WTH? I take Benadryl almost every day during allergy season, and even sometimes for sleep.
Rapid urine drug screens: diphenhydramine and methadone cross-reactivity. - PubMed - NCBI
My question is this: what would happen if I had to submit because of a shortage or something, and I tested positive? Should I just tell them beforehand what I take? Would they maybe use a more specific test? I have no idea how this stuff works.