March 5, 2009 -- The FDA today advised patients undergoing MRI (magnetic resonance imaging) scans to tell their doctor if they're wearing any medicated skin patches, in order to avoid burns at the patch site.
Some skin patches contain aluminum or other metals in their non-adhesive backing, which is the part of the patch that doesn't touch the skin. That little bit of metal can conduct electricity and cause a skin burn at the patch site during an MRI scan.
The FDA has received "fewer than half a dozen" reports of skin burns in patch wearers undergoing MRI, Sandra Kweder, MD, deputy director of the the FDA's Office of New Drugs, said today at a news conference. Those burns, which were all reported in nicotine patch wearers, weren't serious; they were likened to a severe sunburn at the patch site, Kweder notes.
Kweder estimates that less than a quarter of all medicated skin patches contain metal. The FDA is creating a list of those patches, as well as a note that would go on the patch itself, which might read "Remove before MRI."
In the meantime, Kweder says patients should tell their doctor about their skin patch when referred for an MRI and get advice about removing the patch before MRI and replacing it afterward. Patients should also mention it to the staff at the MRI facility when scheduling their MRI appointment and again when they report for their MRI.
Although some patch products already note MRI warnings, others don't have that label yet, and not all of them will need it. Kweder points out that patients can't tell by looking at a patch whether it has trace amounts of metal -- a clear-looking patch could contain tiny amounts of metal. So when in doubt, take the patch off during the MRI and put it back on afterward; that's "the smart thing to do," Kweder says.