After a nearly 2-year study, the US Food and Drug Administration (FDA) has not found any evidence of adverse events from the brain's retention of gadolinium after MRI that uses gadolinium-based contrast agents (GBCAs), the agency announced today.
Accordingly, the FDA will not restrict the use of GBCAs, but it will continue to study their safety, the agency said in a news release. In the meantime, clinicians should continue to use GBCAs sparingly, as the FDA recommended in July 2015. At that time, the agency said clinicians should limit their use to cases in which additional information yielded by the contrast agent is necessary and reassess the need for repetitive MRIs with GBCAs.
GBCAs come in two different chemical structures, linear and macrocylic. The agency's caution about these contrast agents was prompted by reports of gadolinium retention in the brains of patients undergoing four or more contrast MRI scans during the management of conditions such as multiple sclerosis or cancer, even when those patients had normal kidney function. GBCAs are mostly eliminated through the kidneys.
The FDA's review of scientific literature and adverse events reported to the agency showed that linear GBCAs result in more gadolinium retention in the brain than macrocylic GBCAS, according to today's announcement. "However, our review did not identify adverse health events related to this brain retention."
Gadolinium, a heavy metal, can be retained not only in the brain but also in bone and skin. The FDA's ongoing review of GBCAs will look at a rare skin condition called nephrogenic systemic fibrosis (NSF), which is the only known adverse event related to gadolinium retention. Characterized by thickening and hardening of the skin, NSF can involve the joints and significantly limit motion. The disorder occurs in a small group of patients with preexisting kidney failure, although the FDA has come across recent reports of patients with normal kidneys who developed NSF after receiving GBCAs for an MRI. Some of these patients had retained gadolinium in their brains as well. The FDA said it will try to determine whether these fibrotic reactions indeed are linked to retained gadolinium.
More information on today's announcement is available on the FDA's website.
To report any problems with GBCAs, contact MedWatch, the FDA's safety information and adverse event reporting program, by telephone at 1-800-FDA-1088; by fax at 1-800-FDA-0178; online at https://www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htm; with postage-paid FDA form 3500, available at https://www.fda.gov/MedWatch/getforms.htm; or by mail to MedWatch, 5600 Fishers Lane, Rockville, Maryland 20852-9787.
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Cite this: No Harm Seen in MRI Gadolinium Retention in Brain, FDA Says - Medscape - May 22, 2017.