I know so many people that take cymbalta and lyrica at the same time inculding myself a few years back and I had no problems. The combination of Cymbata and lyrica/neurontin is a great combo for rsd.
I take cymbalta an tramadol, and the pharmisist tells me that and i say i have been taken them for months with no problems. I wouldnt be afraid to take them. You will never know until you take them and the doctor wouldnt give them if he didnt feel that it was safe!
I am no doctor, I just speak from experience from myself and others that are on those same meds with no problems!