"no side effects.  in the beginning, they didn&#039;t help much at all and my pain management specialist (neurologist) had to increase my dosage quite a few times until we found a level sustainable.  i am now not as confined to my couch or bed like before.  original dosage began: 12.5mcg 72 hours but no impact in controlling my pain level.  my current dose is 75mcg/48hrs.  i am opiate tolerant and will probably be increased to 100mcg.  in addition to fentanyl, i also take norco 10-325mg 6xday, carisoprodol 350mg 4xday, xanax 1mg at least 1xday and will start taking chantix to stop smoking next week (nov. 30, 2009).  i haven&#039;t had any bad side effects from fentanyl. i like the mylan brand better as it doesn&#039;t irritate my skin."