Hi Sherry,
My doctor told me to increase the fentanyl patches as needed to handle the pain most of the time and to use another drug (Roxicet - a mix of acetomenophen and oxycodeine) for breakthrough pain. She said it was important not to rely on the breakthrough pain drug too much but rather to add another 25 mg. patch anytime the pain was breaking through too frequently.
As Gary said, you can keep adding patches and get up to 300 mg. of fentanyl. and that most of us ended up in the 100-150 range. I would say not to worry about adding sufficient medication to handle the pain. You should pay attention to the constipating aspects of the narcotics, though, and start using Boost (or whatever) with fiber. You can also buy water soluble fiber and add it to his diet. I'd suggest starting to increase the fiber before the constipating effects really kick in.
Also, when treatments are over and the pain begins to diminish (usually a couple of weeks after treatment ends), you should carefully and slowly taper off the patches so that ending the narcotics will not create too much of a withdrawal effect. You can even go from a 25 mg. patch to smaller dosages by placing some clear plastic tape under part of the patch to prevent its absorption into the body.
Good luck with the treatments and remember that despite the pain and suffering of the radiation, it will pass with time and there will be better days ahead. Best, Sheldon