Long-term users of other opiates be warned:
The 12-24 hour guideline to avoid precipitated withdrawal is not for everyone. Heavier users need to wait the full 24 hours or longer before starting Subutex.
I found that out this morning. I tapered down to my last doses of oxycodone- 75 then 30mg 2 hours later (from a lot more, for a LONG time), expecting to be able to take sub in the morning to feel better. 15.5 hours after my last dose, a 6mg Subutex IV put me into pretty severe precipitated withdrawal (I tested a ~.75mg dose before doing the larger dose, it had no discernible effect either way), despite the time and my COWS score. Had to call and beg my mom for money and it took 240mg IV oxycodone to break through the bupe. Not a fun time.