Mothly drops

hey, i have a quick question recently i was busted smokin and now i have to take a monthly drop, can i still smoke and have it out of my system in this time. Also i heard niacin clears ou tyour system, and i found out it is in propel fitness water, if i were to drink alot of it would that work? Also since i was a heavy smoker will it take a long time to clear out. Im around 140 pounds and like 5,9 if that helps. sugestions please.

^ do u workout regurly? hows ur diet? metabolism? theres a lot to put into consideration. b/c im 5 11 200lbs bodybuilder that eats every 2 houres and takes shit loads of supps. and i can get it out og my system in about 3-4 days.