The Food and Drug Administration (FDA) has updated a safety communication regarding the risk of thyroid dysfunction in infants following the use of contrast media containing iodine for X-rays and other medical imaging procedures.

The update was based on the Agency’s recent review of 6 new published studies evaluating this risk, along with 5 earlier studies published in the medical literature that assessed thyroid function in a range of 10 to 2320 children from birth through 3 years of age who were exposed to iodine contrast media (ICM) injections. The reported rate of underactive thyroid cases ranged from 1% to 15%. Neonates, particularly those who were preterm, were at higher risk and patients with cardiac conditions were at greatest risk. Most reported cases were temporary and did not require treatment.

The Agency concluded that “there is compelling evidence of a significant risk of underactive thyroid or a temporary decrease in thyroid hormone levels in newborns and children through 3 years after exposure to ICM.” While the risk of underactive thyroid or a temporary decrease in thyroid hormone levels is uncommon, the Agency recommends identifying the conditions and treating them early if needed to prevent future complications.

In light of the review, a new warning has been approved to the prescribing information for the entire class of ICM injections describing the risk of underactive thyroid or a temporary decrease in thyroid hormone levels. Moreover, the prescribing information will include monitoring recommendations for children 3 years of age or younger. 

The Agency is recommending that health care professionals perform appropriate monitoring of patients from birth through 3 years for the possibility of hypothyroidism or a temporary decrease in thyroid hormone levels following exposure to ICM. Health care professionals should consider evaluating thyroid function within 3 weeks, especially in term and preterm neonates and children with cardiac or other conditions. If thyroid dysfunction is detected, treat and monitor thyroid function as clinically needed.

Adverse events related to ICM or other medicines should be reported to the FDA’s MedWatch Online Voluntary Reporting Form.

References

  1. FDA recommends thyroid monitoring in babies and young children who receive injections of iodine-containing contrast media for medical imaging. News release. US Food and Drug Administration. Accessed March 30, 2022. https://www.fda.gov/drugs/drug-safety-and-availability/fda-recommends-thyroid-monitoring-babies-and-young-children-who-receive-injections-iodine-containing?utm_medium=email&utm_source=govdelivery
  2. FDA Drug Safety Communication: FDA advises of rare cases of underactive thyroid in infants given iodine-containing contrast agents for medical imaging. News release. US Food and Drug Administration. November 17, 2015. Accessed March 30, 2022. https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-fda-advises-rare-cases-underactive-thyroid-infants-given-iodine