Initially, my dr. just prescribed the Opana ER. When I saw him last time I told him that it wasn't lasting the full 12 hrs, that I was only getting about 9-10 worth, and that is when he ordered the Opana IR. I'm suppose to take it at hour 10 on the ER dose. So that means that I take the ER at 7.30 am and pm,and then I take the IR at 5.30 am/pm. Of course, I'm not getting up at 5.30 to take meds, so sometimes, if I need it, I take the IR at about 6.30 and then the ER about 7.30. I figure the norm is about 1 hr either side of the time works for me. I'm also taking it during a flair whenever I need it. (but not more than about 5-6 hrs between). So far it is working ok. I wish their was a cure for the nightmares. It's good to know that it's not just me.

Mary