I agree w/ everyone else, the solution is simple, just tapper down to as low of a dose as you can or wish to. Then stay at that new lowered daily dose for at least 7-10 days and you will have successfully lowered your tolerance. ThE catch of course, is that during the tapering period, you won't be getting "high", your goal during this time is ONLY to lower your daily dosage without getting sick. Essentially its a trade off, you will be giving up that high in return for a lower tolerance. I do have some suggestions though:
1) Opiates work best when taken in a single, large, "bulbous" dose. So IMO, you should first try dosing the same amount, but instead of your say 8 daily doses, make it 3-6 daily doses. You will likely find that by doing this you won't need to take as much drug b/c you will be using it more efficiently, and like magic---instant lowered tolerance.
2) Also, eat some, but preferably all of your pills instead of snorting them. This is another more efficient way to use, resulting in a "lower tolerance" (tolerance not really lowered but the result is the same--less drug w/ same effects)
3) If you do tapper, then definately eat your pills as this will be more efficient and each dose will last longer making the taper easier