Can painkillers be made to last longer?!

I few months ago i was in a car accident and suffered two herniated disks which I have been on pain medication since then. I was given both oxycodone times release and immediate release but I feel the the time release greatly effects my metal alertness and kind of puts me in a fog for the entire day, which really messes my school work up. However I do need something for the pain and cant bare sitting in lecture hall for hours a day without and relief. So since the immediate release do not have these effects on me I have been taking these instead

So my question is there any way to make the immediate release painkillers last longer other then eating food with them to slow the absorption thanks for any help you can giveHealth Question & Answer

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