"i am currently on opana er, and tried the nucynta er to see if it would have any less side effects than those i had on the opana (sweating was the absolute worst, and severe exhaustion, among others). i tried nucynta er for 4 days, and felt the best i have felt in years. while my dose needs to be increased a little, it made me feel so much better. i didn&#039;t have any of the negative side effects that i have on the opana. on the opana, i needed to nap throughout most of the afternoon because i was just that tired. on the nucynta, i had energy throughout the entire day and just felt wonderful. i am excited to get on it permanently, and think it may be an awesome medication for me."