I've only had temgesic for hydro withdrawal, and it didn't seem to do much for my pain. I may have been on a tiny amount, though (I was hospitalized at the time, and they refused to give me hydro because they knew that I got my script from an OP and didn't consider it legit).

I would think the strongest thing you're going to find on an IOP is codeine or dihydrocodeine. I haven't researched it lately, so maybe things have changed.