Welcome to the FDA Drug Safety Podcast for health care professionals from the Division of Drug Information. Based on our recent review of published studies, on March 30, 2022, the FDA recommended that newborns and children through 3 years old have follow-up thyroid monitoring within 3 weeks after receiving injections of contrast media containing iodine, also called “contrast dye,” for X-rays and other medical imaging procedures. Our review showed that underactive thyroid or a temporary decrease in thyroid hormone levels were uncommon. However, the conditions should be identified and treated early when needed to prevent potential future complications. Newborns, particularly those born premature, and children in their first 3 years with underlying conditions such as heart issues may be at higher risk for problems of the thyroid.
We have approved a new warning to the prescribing information for the entire class of iodinated contrast media (or ICM) injections and monitoring recommendations for children 3 years or younger. The warning describes the risk of underactive thyroid or a temporary decrease in thyroid hormone levels. These risks and recommendations pertain to ICM given as an injection through an artery or vein.
Health care professionals should 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. Consider evaluating thyroid function within 3 weeks, especially in term and preterm neonates and children with some underlying conditions. If thyroid dysfunction is detected, treat and monitor thyroid function as clinically needed to avoid future cognitive and other developmental disabilities.
Certain pediatric patients are at an increased risk, including those who are newborns or have very low birth weight, prematurity, or the presence of cardiac or other conditions such as those requiring care in neonatal or pediatric intensive care units. Patients with cardiac conditions may be at greatest risk since they often require high doses of contrast during invasive cardiac procedures.
Since 2015 when FDA first alerted the public about cases of underactive thyroid in infants receiving ICM, six new research studies evaluating this risk have been published. We reviewed these six studies and the five earlier ones published in the medical literature that assessed thyroid function in a range of 10 to 2,320 children from birth through 3 years who were exposed to ICM. Most cases of decreased thyroid hormone levels were temporary and did not require treatment. The reported rate ranged from 1 percent to 15 percent and tended to be higher in newborns, particularly those who were preterm. Patients with cardiac conditions were at greatest risk since they often require high doses of contrast during invasive cardiac procedures such as catheterization and computed tomography. The time from ICM exposure to diagnosis ranged between 8.5 and 138 days, with most occurring within 3 weeks in some of the publications.
In 2015, we required the manufacturers of ICM products to conduct a study to investigate this safety issue further. However, we have concluded based on our review of the published studies that there is compelling evidence of a significant risk for underactive thyroid or a temporary decrease in thyroid hormone levels in newborns and children through 3 years after exposure to ICM; therefore, the study by the manufacturers is no longer needed.
Side effects involving ICM and other medicines should be reported to FDA’s MedWatch reporting program at www.fda.gov/medwatch.
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