Benzocaine is a local anesthetic found in many over-the-counter topical pain relief products, such as gels, sprays, or liquids. These products were historically used to temporarily numb minor oral pain, including discomfort from teething. However, major health organizations, including the U.S. Food and Drug Administration, have issued strong warnings against using benzocaine products in infants and young children. This medication carries a rare but serious health risk that can quickly become life-threatening, providing little benefit compared to the potential harm.
The Specific Risk: Methemoglobinemia
The primary danger of benzocaine use in infants is the induction of a serious blood disorder known as methemoglobinemia. This condition directly interferes with the blood’s ability to transport oxygen throughout the body. Hemoglobin, the protein in red blood cells, normally carries oxygen via iron molecules.
When benzocaine is absorbed, it chemically alters the iron within the hemoglobin molecule, changing its state. This altered form, called methemoglobin, is incapable of effectively picking up or releasing oxygen to the body’s tissues. If too much methemoglobin builds up, the body becomes starved of oxygen. This lack of oxygen delivery can lead to serious consequences, including permanent brain and nerve damage, and can result in death if not immediately treated.
Why Infants Are Uniquely Vulnerable
Infants under two years old are at the highest risk for developing benzocaine-induced methemoglobinemia compared to older children or adults. Their smaller body mass means that even a small dose can result in a higher concentration relative to their size. Furthermore, the thin mucous membranes in an infant’s mouth allow for faster absorption of the drug into the bloodstream.
The immaturity of the infant’s enzyme systems is the most significant physiological factor. The body naturally produces small amounts of methemoglobin, and a specific enzyme, NADH-cytochrome b5 reductase, works to continuously convert it back to normal hemoglobin. Infants have lower levels of this enzyme, making them less capable of reversing the toxic effects of benzocaine. Consequently, methemoglobin levels can rise quickly and reach dangerous concentrations before their body can restore balance.
Recognizing Symptoms and Immediate Action
Parents should be aware of the signs of methemoglobinemia, which can appear within minutes to hours after benzocaine exposure. A noticeable symptom is the skin, lips, or nail beds turning pale, gray, or a bluish color, reflecting the lack of oxygenated blood. The infant may also exhibit shortness of breath or difficulty breathing.
Other symptoms include unusual fatigue, lethargy, or a lack of responsiveness. A rapid heart rate may also be present as the body attempts to compensate for poor oxygen transport. If any of these signs appear after using a benzocaine product, parents must immediately stop use and seek emergency medical help. Calling emergency services or going to the nearest hospital emergency room is the required course of action, as this condition requires prompt medical intervention.
Official Warnings and Safe Alternatives
The U.S. Food and Drug Administration (FDA) has warned against using over-the-counter benzocaine products for treating pain in children under the age of two. The agency states these products offer little benefit for conditions like teething pain, as they often wash away quickly with saliva, and the serious risk outweighs the temporary relief. This warning applies even if a product does not explicitly carry a contraindication on the label. Instead of topical anesthetics, parents should use safer, non-drug methods to soothe discomfort.
Non-Drug Alternatives
Gently massaging the baby’s gums with a clean finger can provide relief. Another effective alternative is to allow the child to chew on a firm rubber teething ring that has been chilled in the refrigerator. Teething rings should never be frozen, as extremely hard objects can harm the gums. For more significant discomfort, parents should consult a pediatrician about the appropriate use and dosage of non-topical pain relievers, such as infant acetaminophen or ibuprofen.