"i have been on the fentanyl patch for 8 years and decided that i was so tired of the brain fog that i had from this drug that i asked the doctor to put me on kadian and i don&#039;t have the brain fog anymore and kadian keeps my pain level down enough for me to function in everyday life, i have crps and spondylosis in my neck with two bulging disc so no surgery for me. my only complaint is constipation."