Parents and caregivers should know that over-the-counter products containing the active ingredient benzocaine for relief of teething pain in infants and toddlers are not only ineffective but can cause methemoglobinemia, a rare but serious, potentially fatal blood disorder, according to a safety announcement from the U.S. Food and Drug Administration.

These benzocaine-containing products are available as gels, sprays, ointments, lozenges and liquids, and are sold under the brand names Anbesol, Baby Orajel, Cepacol, Chloraseptic, Hurricaine, Orabase, Orajel and Topex, and also as store brands and generics, according to the FDA news release, which warned in May against use of these products in infants and children under two.

The FDA urged parents and caregivers to read the Drug Facts labels when using over-the-counter products to see if benzocaine is an active ingredient, and when uncertain, to ask a pharmacist or health care professional for assistance.

Methemoglobinemia is a condition in which too little oxygen reaches the cells due to abnormally-high levels of methemoglobin, a type of hemoglobin. Hemoglobin is the protein in red blood cells that typically both carries and distributes oxygen throughout the body – however, methemoglobin is a particular type of hemoglobin that can only carry but cannot distribute oxygen.

Initial warning signs of methemoglobinemia include chocolate brown colored blood and cyanosis, in which the skin and especially the lips and fingers take on a bluish tone. The disorder is also known as “Baby Blue Syndrome.” As the condition progresses, more serious symptoms such as shortness of breath, rapid heart rate, nausea, fatigue, confusion, stupor and loss of consciousness can occur.

“Children can obviously suffer horribly from something like this,” Eva Kubiczek-Love, Cleveland Clinic pediatrician, states in a video on the clinic website. “If you have your hand on a bottle of something you’ve never given your child before and you have your phone, there’s no reason why you can’t look at the FDA website or even, if you’re very concerned, call your pediatrician right then and there before you even buy it.”

Methemoglobinemia symptoms can occur within minutes and up to one to two hours after applying benzocaine for the first time or after several uses.

The FDA told manufacturers to stop marketing such products to this young population including placing warning labels on products about the risk of methemoglobinemia. The FDA also wanted warning labels as well as updated product directions that instruct parents not to administer the product to infants and children under two years. The FDA threatened to remove the products from the market should manufacturers fail to comply.

But benzocaine is not the only issue when it comes to teething pain relief products. In January, 2017, the FDA issued a warning about Hyland’s brand homeopathic teething products due to concerns over belladonna, a toxic substance found during laboratory analysis for which there are no known safe levels in children. The manufacturer initially refused to recall the products but four months later in April issued a nationwide recall of its Hyland’s Baby Teething Tablets and Hyland’s Baby Nighttime Teething Tablets.

In 2016, Raritan Pharmaceuticals voluntarily recalled three homeopathic products that contained belladonna, including CVS Homeopathic Infants’ Teething Tablets as well as two children’s liquid ear relief products, including one likewise marketed by CVS.

The FDA further advised that all topical analgesics intended to relieve teething pain, regardless of their active ingredients, are inherently ineffective due to their washing out of a baby or child’s mouth within minutes of application, and recommended globally against their use.

In the event of teething pain, the agency instead suggested that parents rub or massage the child’s gums with one finger and use a firm teething ring, in accordance with American Academy of Pediatrics recommendations.

The FDA advises adults and children over two years of age to use all benzocaine-containing products sparingly, only as needed, and not more than four times a day.