How do fentanyl patches work?

Blocks pain : Fentanyl is an opioid analgesic. Fentanyl interacts predominately with the opioid mu-receptor. These mu-binding sites are distributed in the human brain, spinal cord, and other tissues.Fentanyl exerts its principal pharmacologic effects on the central nervous system. In addition to analgesia, causes alterations in mood, euphoria, dysphoria, and drowsiness.

Provide pain relief: Fentanyl patches are small patches like a band-aid. The medicine is mixed into the bandage material. Once it is applied to the skin, the fentanyl, an opiate medication, slowly dissolves through the patient's skin and is ultimately absorbed into the blood so that it circulates throughout the body providing pain relief. The patches come in different doses affecting length of time they work.