Metabolism of Fentanyl

Fentanyl is a powerful opioid pain reliever that the FDA classifies as a Schedule II drug. It acts on your central nervous system in a way that increases the risk of drug abuse.

Pharmacology

• Fentanyl interacts with the opioid mu-receptors in your brain, spinal cord and other parts of the central nervous system to relieve severe pain.

Dosage Forms

• Fentanyl is available as a transdermal (across the skin) patch, a buccal (oral dissolving tablet) form and a transmucosal (across the mucous membranes) patch that's placed in the mouth.

Absorption

• Fentanyl is absorbed at a constant rate from transdermal and transmucosal patches, builds up in the tissue below the patch, is absorbed into the bloodstream and travels to the mu-receptors. The buccal tablets dissolve slowly in your mouth before being absorbed into the bloodstream.

Peak Effect

• After you apply a fentanyl transdermal patch, the level of fentanyl in your body will rise to a peak between 12 and 24 hours later. A buccal tablet will peak at three to four hours and a transmucosal patch in the first hour.

Duration

• The transdermal patch provides a steady level of fentanyl for up to 72 hours. The buccal tablet's effect levels off around 12 hours after you take it. The effect of the transmucosal patch drops significantly after four hours.