MRI scanner
The US Food and Drug Administration (FDA) has issued new safety-related requirements pertaining to gadolinium-based contrast agents (GBCAs) used for magnetic resonance imaging (MRI).
The agency’s action is due to the fact that gadolinium can be retained in patients’ brains and other body tissues for months to years after they receive GBCAs.
The only known adverse event related to gadolinium retention is nephrogenic systemic fibrosis, which occurs in a small subgroup of patients with pre-existing kidney failure.
Patients with normal kidney function and gadolinium retention have experienced adverse events involving multiple organ systems. However, the FDA has found no evidence confirming that gadolinium retention is causing these events.
Therefore, the agency concluded that the benefit of all approved GBCAs continues to outweigh any potential risks.
Still, the FDA has issued the following safety requirements related to GBCAs:
- Patients receiving GBCAs must read a new medication guide explaining about gadolinium retention
- Manufacturers of GBCAs must conduct human and animal studies to assess the safety of GBCAs
- Labels of GBCAs must be updated with a “Warning and Precaution” about gadolinium retention
- Labels must be changed to include mention of gadolinium retention in the Adverse Reactions, Pregnancy, Clinical Pharmacology, and Patient Instructions sections.
The FDA is also recommending that healthcare professionals consider the retention characteristics of each agent when choosing a GBCA for patients who may be at higher risk for gadolinium retention. This includes patients requiring multiple lifetime doses, pregnant women, children, and patients with inflammatory conditions.
In its latest safety communication on gadolinium retention, the FDA noted that linear GBCAs result in more and longer retention than macrocyclic GBCAs.
Specifically, gadolinium retention is higher with Omniscan (gadodiamide) or OptiMARK (gadoversetamide) than with Eovist (gadoxetate disodium), Magnevist (gadopentetate dimeglumine), or MultiHance (gadobenate dimeglumine).
Gadolinium retention is lowest with Dotarem (gadoterate meglumine), Gadavist (gadobutrol), and ProHance (gadoteridol), which all have similar levels of gadolinium retention.
Finally, the FDA is recommending that healthcare professionals minimize repeated GBCA imaging studies when possible, particularly closely spaced MRI studies. However, necessary GBCA MRI scans should not be deferred or avoided.
The FDA said it is still assessing the health effects of gadolinium retention and will update the public when new information becomes available. In the meantime, patients and healthcare professionals can report adverse events involving GBCAs to the agency’s MedWatch program.
