I have been using fentanyl
patches for nearly ten years. I prefer fentanyl patches with the gel inside. They seem to work and stick better. Unfortunately, I cannot find them anywhere anymore. Only fentanyl patches with a matrix are available now. Maybe it depends on the different countries and the labs that make them.
My personal preference goes to fentanyl patches that are brand name (Duragesic or Durogesic
, depending on the countries), that is, those that are made by Janssen Pharmaceutica. I always tell the pharmacist I do not want generic fentanyl patches because they make me much, much sicker than the brand name ones. Could it be because they cause withdrawal
by containing up to - 15%/20% fentanyl (they would still be considered bioequivalent).
Exemple: a dosage of 125 mcg fentanyl patches every 72 hours
125 X 15 = 1875 or 125 X 20 = 2500
1875 : 100 = 18.75 or 2500 : 100 = 25
125 - 18.75 = 106.25 or 125 - 25 = 100
If 125 mcg generic fentanyl patches contain 15% less fentanyl, you will get patches with 106.25 mcg (instead of 125 mcg) and if 125 mcg generic fentanyl patches contain 20% less fentanyl, you will get patches with 100 mcg (instead of 125 mcg). To me, it is a big difference. My U.S. pain management confirmed this; he does not want me using generic fentanyl patches: on his prescriptions, he checks "do not substitute".