"i was put on duragesic (fentanyl) for severe back and migraine pain. oxycontin and percocet didn&#039;t touch it. i am allergic to codeine and hydrocodone. at first the patches were a god send- the first 24 hours were hell (vomiting, dizziness, heart racing) but it got better when my body got used to medicine. unfortunately about 6 months later i would lose track of hours of time. people said that i would &quot;zone out&quot; during conversations and just stare at the wall. next came spasms. i would have horrible cramps in my legs. my toes would curl up, my legs would start to shake. i had to step down off the patch 25mgs at a time. once out of my system the spasms stopped. "