How long does tha prescription medicne, Dilaudid take to get out of ur system?

Question:

Gotta take a drug test tomorrow & i took some yesterday. I just took some Niacin cause i've heard that it'll help in cleaning ur system out from anything that'll show up on a drug test.

Answers:
the niacin thing is not always true. Dilaudid is 3-4 weeks. by the way, that is some hardcore stuff, becareful. dilaudid is chemically similar to heroin