Annabel,
Fentanyl patches were an excellent tool for managing pain during my treatment. I started with a 25 mg patch and ended up at 175 mg. for the 2 weeks following the end of treatment. Those were the worst weeks of the whole process. I also used oxycodeine in liguid form for breakthrough pain, putting it through my PEG to get quick relief.

As Gary mentions, it is very important to have someone managing your Mom's pain and I think, equally important, managing the tapering off process when reducing the amont of pain killers. The patches can come in 25 or 50 mg increments, as I recall, and you want your Mom to taper off gradually. I did it in 25 mg. doses. If that becomes too uncomfortable, you can cut a patch in half and come down more slowly in 12.5 mg doses.

Best, Sheldon