I was prescribed Opana after I told my doctor I no longer wish to take Vicodin. Initially the 5mg dosage put me to sleep after relaxing the nerve pain in my back and legs. (I only take it at bedtime) After the first month I discovered that I was waking up after a couple hours of sleep with neck and head aches. Since I have had these aches before if I do not sleep properly (too many pillows etc.) I didn't think much about it. After a bout with a bad cold and awful headaches that woke me up after only 2 to 4 hours of sleep, I discovered it was only when I would take the Opana. I would have to get up, take a 600mg Motrin to dull the headache and go back to bed in about two hours. The dull headache doesn't really go away, just gets less noticable. I will be advising my doctor on my next visit I will no longer take the medication due to the headache side effect which is more painful than the pain I was taking the drug for.