I had a similar issue with cosentyx. While it was effective for the disease. It was destroying me. I was so lethargic, I'd literally pass out at 3pm until the next day. I literally felt like I was being poisoned at best I felt like I had just woken up from general anesthesia. I lost 30 pounds in loading stage alone. I couldn't take the side effects. I still encourage people to try it, since everyone is different. But hopefully you don't feel as bad knowing others have had difficulties with Cosentyx. Since this med is knew I don't think docs are really so aware of the side effects yet. Like I said don't let your situation discourage others from trying it though. I know a lot of people on the psoriasis forums that are doing amazing on it.

diagnosed at 32.
HLA B27 Positive
Currently on Simponi, Tramadol, and celebrex