I have used Cymbalta in the passed, its the only med that lower my feet pain caused by neuropathy, but that's not my story. I went in for back surgery, they started to put me out , before first cut, I had cardiac arrest, 3 session of cpr to get heart going again.I feel what happened to me was they had mixture of fentanyl in anesthesia which caused serotonin syndrome. Dr's would not confirm this.after release from hospital check on drugs.com is there any interaction between Cymbalta & fentanyl the answer was a big yes, it can cause cardiac arrest. I have been put out since several time,I always tell my story first with the interaction of the 2 drugs so they always make sure i have no fentanyl in there mixture. Needless to say I no longer take Cymbalta even tho it helped with pain.Its a different story how to wein yourself off of Cymbalta, Good luck on future surgery