Fentanyl is an extremely powerful narcotic analgesic....a STRONG painkiller. It is used primarily in hospitals in IV's for post operative pain, and also as a medication for people on ventilators to keep them comfortable. Where morphine is generally administered in 'milligrams', like 2-4 mgs per dose, fentanyl is administered in 'MICROgrams'...usually 50 to 100 per hour. So you can see, it is CONSIDERABLY stronger than morphine. Fentanyl is also delivered by a patch...usually for chronic pain, like back problems, cancer, etc. This medicine, btw, is HIGHLY addictive. It's used for "severe" pain.
Percoset and Percodan are pills that contain the narcotic painkiller "oxycodone", which is also very addictive. It's the medicine that is in the more popular "Oxycontin", AKA "hillbilly heroin". Percoset also contains acetominophen (tylenol) while Percodan contains ASA (aspirin). They have relatively low amounts of oxycondone, but they are still both very addicting. Used for moderate pain, they will do pretty much exactly the same thing. Percosets are generally prescribed more often because they don't have "aspirin" in them.

