Have you ever tried anything that is slow or time released? I'm on Kadian, which is morphine but released slow. I'm sure there is something equivalent to Oxycodone that is time released. I also agree that eating something helps. Best of luck, and hope you find something that works.
I have to add here that since it seems to be happening with all meds your taking or have taken for pain even the tramadol that you might consider a drug reaction. YOu didnt state what else you were taking but if you rlike most of us the first thing you get into you in the morning is your pain meds and then you work on whatever else you have to take and it may even be something you take later in the day that can affect it.
So many meds out there can cause a reaction to occur when they come together and even may effect some an dnot others or at differing levels of severity.
To name a few that can and do interfere pay particular attention to the ones to treat GERD,acid reflux,IBS, and even some of the Vits and minerals used for replacement therapy. Also meds use to slow down or speed up absorptions times in the digestive tract as well as the urinary tracts such as those used for bladder incontinence or spastic bladders can cause side effects with opiates.
A OTC med used for UTI's sold as "uristat" and store brand names can wreck havoc with opiate treatment as it has a tendancy to decrease the levels of opiates in your blood stream at any given time making your pain med all but useless.
There are some wonderful sites via the net that deal with drug interactions and a google search can bring some of those up for. They are going to ask you to put in all of the meds you take and be sure to put even supplements such as ensure,boost,any of those along with iron or other minerals and vits you take occasionally or on a daily basis. OTC meds need to be added as well especially those like immodium,pepto,tums,some of those things you dont consider meds as they also can have interactions with opiate uses.
I want to point out here also that alot of fruit juices and especially the citric ones can and do effect absorptions rates of opiates so you also might want to google these and if you come up with anything during your search that looks suspicious print it out and take it to your Doc,it may be switching times of meds or simply types can make a difference for you.
Good luck to you and please let us know what pops for you in the search.