this is day 6 or 7 on the sub, 16mg also, and i have pounding killer headaches, but take heed and listen to these fine people here as they have suggested that 16 mg is way toooooooooo much sub to be taken, i've cut back to 6mg at 10pm & another 4 or 6mg at 10-11am, still have the headaches and the nausia, but i'm gonna cut back more of the sub, i'm just getting over a hydro addiction, and now i certainly dont need a subox addiction !!!