The U.S. Food and Drug Administration (FDA) is now requiring a black box warning on viscous lidocaine, emphasizing that it should not be used on infants who are teething. Medpage Today reports that a new boxed warning will be added to labels for 2% oral viscous lidocaine products, which are available by prescription, indicating that such use “can cause serious harm, including death.”

According to Medscape Medical News, the FDA reviewed 22 case reports of serious reactions, including deaths, in infants and young children who were given the lidocaine solution to treat mouth pain or who accidentally ingested it. In particular, where a child was given or accidentally swallowed an excessive amount, there were cases of seizures, severe brain injury, and heart problems.

The journal American Family Physician explains that a black box warning, also known as a boxed warning, is a warning issued by the FDA and featured in the labels of drugs associated with serious adverse events. These safety concerns are typically identified through the FDA Adverse Event Reporting System and the FDA’s Office of Surveillance and Epidemiology, which evaluates postmarket safety findings. The most common type of warning is issued when there is a potentially serious adverse effect that must be carefully weighed against the potential benefit of the drug.

WebMD offers help for parents that have children who are currently teething. Teething normally begins around 6 months of age and all 20 primary teeth should be in by the time the child is three. Teething can cause pain and irritation for the child, causing them to be fussier, drool, and even experience rashes and other symptoms. Pharmaceutical remedies should not be used, and WebMD suggests offering the child safe and clean objects, such as teething rings, to chew on.