Transdermal medicine patches are worn by an increasing number of patients to ensure optimal drug delivery of a variety of medications. Widely known for the delivery of nicotine to aid in the cessation of smoking, drug patches are used for a multitude of indications across a varied slice of the population worldwide.
Uses Of Transdermal Patches
The uses of transdermal patches include (but are not limited to) the following:
- Hormones
- Narcotics
- Nicotine
Many of these patches contain small amounts of metal in the backing. Via the conduction of electricity during an MRI scan, this metal can overheat and cause skin burns to the skin area directly in contact with the patch.
An MRI Scan, unlike a CT scan or an x-ray, does not use radiation to image the body but uses radio waves and a magnet, creating a magnetic field about 10,000 times greater than that of the earth itself. For this reason, any metal present inside or on the patient's body, held by the staff or present in the MRI scanning room can be impacted.
Items not Allowed in an MRI
In addition to the recent warning on transdermal patches, the following items are not allowed or can preclude a patient from participating in an MRI Scan:
- Pacemakers
- Brain aneurysm clips
- Certain artificial heart valves
- Cochlear (inner ear) implants
- Some (recent) artificial joints
- Older Vascular stents
- Sheet metal workers or those in contact with small metal fragments are often referred for a pre MRI skull x-ray to rule out metal in the eye.
Objects not allowed in the MRI room can include the following (these items can either be thrown across the room, suffer damage or distort the MRI image):
- Pens
- Pocket knives
- Silverware
- Eyeglasses
- Jewelry
- Watches
- Credit cards
- Hearing aids
- Pins
- Hairpins
- Metal zippers
- Removable dental work
Transdermal Patches Included In FDA Advisory
As not all of the transdermal patches containing metal have been labeled correctly in the manufacturing process, the FDA has issued a public advisory.
This advisory applies to the following:
- Transdermal patches prescribed by physicians
- Patches obtained by consumers "over the counter" (at the drugstore or supermarket)
- Generic transdermal patches
- Brand name transdermal patches
FDA Recommendations Regarding Transdermal Patches and MRIs for Professionals
The FDA is recommending the following for medical professionals:
- Identify patients that may be wearing a transdermal patch and advise patients about the proper removal and disposal of these patches before an MRI scan (with instructions for replacing with appropriate patch after the scan).
- MRI facilities should take heed and follow published safe practice recommendations concerning patients requiring patch therapy.
FDA Recommendations Regarding Transdermal Patches and MRIs for Patients
Recommendations from the FDA for MRI patients utilizing transdermal patches include:
- Informing the referral physician of patch use and informing him of the indication of use (why the patch is being used; pain, smoking cessation, hormone balance, etc.).
- Asking the physician for instructions on proper removal, disposal and replacement of patches prior to, during and after the MRI.
- Informing the MRI staff of patch usage when booking the MRI appointment, on intake (history) paperwork and prior to the MRI scan.
The FDA is continuing to collect skin burn data from both patients and professionals and urges reports both online at http://www.fda.gov/medwatch/index.html or by phone at 1(800) FDA-1088.
Sources:
U.S. Food And Drug Administration
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