Hi I Just Had A Complete Knee Replacement Jan 17th.

Hi I just had a complete knee replacement Jan 17th. They prescribed oxycodone + Tylenol. I have cut it down to 1 pill + 1 Tylenol every 4-5 hours, from 2 pills every 4 hours, but I can't seem to get to 6 hours. What is a ball park time that ppl stay on these drugs. I hate it because of itchiness and constipation. Don't laugh but I swear I just saw something run across the floor.