The FDA has issued a warning that in rare cases, use of the pain-and-itch benzocaine sprays, gels and liquids can cause methemoglobinemia, a sometimes-fatal blood disorder. With summer on the way, along with sunburn, insect bites and rashes, it’s important to remember that most substances that go on the skin travel into the bloodstream, and that even without methemoglobinemia, overuse of benzocaine can be fatal.
Benzocaine numbs skin pain by blocking nerve impulses, and is found in dozens of products, including medications for sore throat, itching, sunburn, insect bites, rashes caused by poison ivy or poison oak, gum and tooth pain (from teething to denture pain), cold sores, shingles, hemorrhoids, acne, earache and vaginal pain. Benzocaine is found in many throat lozenges and sprays. If there’s a skin pain, there’s likely a benzocaine medication to treat it.
Benzocaine may also be used to block pain any time a doctor is going to insert something into an orifice, including the nose, mouth, throat, urinary tract, vagina or rectum.
Benzocaine overdoses have been caused by applying a spray or gel to large amounts of skin, such as during hair removal, and covering the area with a bandage.
Symptoms of severe benzocaine overdose include irregular heartbeat, seizure, coma, slowed breathing or respiratory failure (breathing stops), but it’s not uncommon to experience an irregular heartbeat, shortness of breath and headache when using benzocaine—it’s just that most people aren’t aware that the benzocaine is causing those symptoms.
Women who are pregnant or nursing should not use benzocaine, and the FDA advises that it shouldn’t be used on children under two years of age, even though it’s found in many over-the-counter teething medications.
The symptoms of methemoglobinemia include bluish coloring of the skin, headache, fatigue, shortness of breath and weakness or lack of energy.
Benzocaine can be a useful medication when used carefully, but it’s important to be aware that it can have side effects that range from mild to fatal.
Aloe gel is a good alternative to benzocaine sprays for sunburn such as Solarcaine.
For details on how creams, lotions, gels and sprays can enter the bloodstream, read Health Risks Can be Skin Deep.