First off, it takes a lot of oxy to od, at least a lot more than 15mg lol. Since you're taking them for actual pain what I would ask you doctor to do is raise it to a 7.5mg or 10mg percocet pills with 325mg of tylenol. Take 3 a day as needed for pain. Trust me man, there's no risk of oding or hurting your liver with the mg you're taking. Also, I wouldn't recommend taking tramadol with oxycodone. The best bet for making your pain pills work again is just upping the dose a few mg. If the pain persist, after you up the dose you should talk to you're doctor and switch to a stronger opiate, though oxy is generally accepted as the strongest, hydromorphone and fentanyl are much more potent and provide quick relief. With all that being said, I have to ask is your pain chronic or acute, meaning is it pain that will last a long time or will the pain go away in a period shorter than 2 months? If you're planning on being on a long term pain treatment you're best option might be Oxycontin or fentanyl. Oh yeah, Max recommended amount of tylenol a day is 4000mg, though I have taken near 7000mg without any problems. I'm not recommending you do that, but just know it takes massive amounts of tylenol to cause medical problems. The maximum dose of oxy you can take without oding varies. I have taken near 150mg at once, over 200mg in a day. At you're tolerance level I'd say you would risk oding if you took anywhere over 70mg or so. Though that is just an educated guess given your current prescription.