Fentanyl (note the correct spelling) is a synthetic painkiller marketed under the name Duragesic. It is far more potent than morphine, and many here have found it very, very helpful. The patch, which comes in various strengths, allows the drug to be absorbed through the skin.
Note that the instructions for using the patch must be followed to the letter.
If you do a search of these message boards for fentanyl or Duragesic, you will get a lot of information. The search link is in small type in the center at the top of every message-board page, under the New Topic and Post Reply buttons. Be sure to "Search All Open Forums" to get the most results.
-- Leslie