"after failed back fusion surgery l4 l5 s1 nothing would touch the pain until opana er. i was taking 20 mg three times daily and have cut back to 5 mg 3 times daily with significant pain increase because i thought i was losing my mind. i seem to have built up a tolerance and either need to increase again dramatically or find something else.  have heard that you can easily build tolerance to opana.  i am your proof. "