This is my second month on Opana. I've been on some kind of opiate for 16 years. Chronic Nerve pain, arthritis of spine, herinated disc, etc. Also Fibro, IBS, Cervical and Lumbar radialopathy and others. One day I missed my 2pm pill of Opana and after 12 hours went into the strongest pain flare-up, to the point that I could not handle it. My pain doctor wants me to stop Opana two days befor surgery. Why & how???