Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health

Introduction: Topical benzocaine is a local anesthetic commonly used to relieve pain caused byteething, periodontal irritation, burns, wounds, and insect bites. Oral preparations may containbenzocaine concentrations ranging from 7.5% to 20%. Pediatric exposure to such large concentrationsmay result in methemoglobinemia and secondarily cause anemia, cyanosis, and hypoxia.

Methods: This is a retrospective study of exposures reported to a statewide poison controlsystem. The electronic health records were queried for pediatric exposures to topical benzocainetreated at a healthcare facility from 2004 to 2014. Cases of benzocaine exposure were reviewedfor demographic and clinical information, and descriptive statistical analysis was performed.

Results: The query resulted in 157 cases; 58 were excluded due to co-ingestants, or miscodingof non-benzocaine exposures. Children four years of age and younger represented the majorityof cases (93%) with a median age of 1 year. There were 88 cases of accidental/ exploratoryexposure, while 6 cases resulted from therapeutic application or error, 4 cases from adversereactions, and 1 case from an unknown cause. Asymptomatic children accounted for 75.5%of cases, but major clinical effects were observed in 5 patients. Those with serious effectswere exposed to a range of benzocaine concentrations (7.5-20%), with 4 cases reportingmethemoglobin levels between 20.2%-55%. Methylene blue was administered in 4 of the casesexhibiting major effects.

Conclusion: The majority of exposures were accidental ingestions by young children. Most exposuresresulted in minor to no effects. However, some patients required treatment with methylene blue andadmission to a critical care unit. Therapeutic application by parents or caregivers may lead to adverseeffects from these commonly available products. [West J Emerg Med.2017;18(5)923–927.]