The U.S. Food and Drug Administration (FDA) is advising that rare cases of underactive thyroid have been reported in infants following the use of contrast media containing iodine, also called “contrast dye,” for X-rays and other medical imaging procedures. In all of the reported cases, the infants were either premature or had other serious underlying medical conditions. Available evidence leads us to believe that this rare occurrence is usually temporary and resolves without treatment or any lasting effects.

We have approved changes to the labels of all iodinated contrast media (ICM) products to include information about these cases. We do not recommend changes to current prescribing, administration, or monitoring practices. We will continue to evaluate this issue and will update the public when we have additional information. Manufacturers of ICM products have been required to conduct a study to investigate this safety issue further.

Parents and caregivers should contact their baby’s health care professional for additional information or if they have questions or concerns about their baby receiving an ICM product. Infants typically do not show any visible signs of underactive thyroid. The thyroid is a gland in the neck that releases hormones. Health care professionals should continue to follow the label recommendations for ICM products. They should continue to use their clinical judgment to determine if testing for underactive thyroid is necessary.

ICM are drugs containing iodine that are given to patients to enhance the ability to see blood vessels and organs on medical images such as X-rays or computed tomography (CT) scans (see Table 1 below for a list of products). These images provide greater detail when necessary to help health care professionals diagnose potential problems.

A search of the FDA Adverse Event Reporting System (FAERS) database identified 10 cases of underactive thyroid reported between 1969 and early 2012 in infants younger than 4 months who received ICM. FAERS includes only reports submitted to FDA, so there may be additional cases about which we are unaware. In addition to ICM, several of these infants also received a topical iodine product that is no longer recommended for young infants, and that may have contributed to their underactive thyroids. All of the infants were diagnosed with underactive thyroid within a month of receiving ICM. Some infants were treated and improved while others improved without treatment.

We will continue to evaluate this safety issue and will update the public when additional information is available. The goals of the study that we are requiring the manufacturers to conduct are to determine how often underactive thyroid occurs with ICM use, how long this temporary condition lasts, and if treatment is needed.


Posted on the FDA website on 17 November 2015