Here is an interesting article on the problem of opiates and Fibromyalgia: Are Opiates Really That Bad for Fibromyalgia?
Studies have shown that daily opiate treatment is not effective. I should put on a side note that they also say exercise is the best treatment... but how to do That without some sort of pain control I have no clue. Exercise is painful even insanely slow exercise.
However the author rightly points out that this is Based on small studies of less than a hundred people. Making statements based on small studies always annoys me. Those small studies are sometimes fascinating and I always think, yes, more research is needed. But conclusive? Not by far.
She also points out that the studies are based on daily long term opiate use. As we all know this creates tolerance to the medication over time and more of the medication is needed. There is even the issue, in some cases, where doing so increases pain sensitivity over time. However, as she states, no one looks at taking pain meds as needed for flares. Which is a very logical choice really.
In her practice she is looking at less than ten days on of the month taking an opiate.
Now, I assume this depends on level of pain experienced by the person with fibromyalgia and any comorbid conditions.