For a while I was on hydrocodone-apap 10/325 and switched to oxycodone-apap 10/325 a few months ago. Both last about 3 hours for me. I can't take an extended release medication because it causes hyperalgesia. So it kind of sucks because I take my medication every 4-6hrs and my ability to use other pain modalities is limited due to other medical conditions, although I use them when possible. I have an incredibly fast metabolism; the doctor and I believe that's what's contributing to the short-life of the medication. How long do your IR (instant release) medications work for you?