Benzocaine-induced methemoglobinemia.

Severe methemoglobinemia developed in a healthy 14-month-old infant following the topical application of a benzocaine-containing gel administered for the relief of the discomfort of teething. Congenital methemoglobinemia and hemoglobin M disease were excluded by appropriate laboratory studies. The patient is considered to have a normal methemoglobin-reducing capacity and her response to the drug is one that presumably could occur in any other child of comparable age on receiving an equivalent dose of benzocaine. Parents should be cautioned against the indiscriminate use of similar medications, particularly since the process for which these medications are administered is both benign and physiologic.