UMEM Educational Pearls

Category: Toxicology

Title: Toxicity of Patches

Keywords: transdermal, fentanyl, clonidine (PubMed Search)

Posted: 6/12/2008 by Fermin Barrueto, MD (Updated: 7/4/2022)
Click here to contact Fermin Barrueto, MD

Trandermal Delivery Systems

  • Uses a gradient (high concentration drug in patch) and a matrix to facilitate transdermal absorption
  • Patch often contains up to 100x the amount of drug that is on the label (ex: fentanyl 100mcg/hr actually = 10 MILLIGRAMS of fentanyl in patch)
  • When prescribing the following will increase absorption: sweating, heat, swallowing the patch, trying to eat the gel in the patch
  • Fentanyl and clonidine are the two most lethal patches on the market in regards to toxicity.
  • Rarely needed in the ED, shouldn't be prescribed except in rare instances