Right now, I am being prescribed 2, 15mg opana er pills a day. The problem though, is that even though I know the pills are supposed to last for 12 hours, they are not. They usually last for about 7-8 hours, then the pain starts coming back and is even stronger. I was wondering if I could be prescribed 3, Opana ER's a day, instead of 2, to keep the pain from coming back?