Try asking for Ethex "brand" OC's. Purdue (the company who makes OP's and made OC's) supposedly is having Ethex sell the originals for them, Walgreens may have it.
If not try seeing if your doc will switch you to Roxicodone, which is instant release oxycodone. It's good stuff, but do NOT get the Mallincrockt (sp?) brand, they are worthless.