Background: Doxylamine is a first-generation antihistamine similar in structure to diphenhydramine. Unlike diphenhydramine, however, there is a paucity of data regarding the risk of toxicity following unintentional exposures in pediatric patients.
Methods: We performed an observational case series with data collected retrospectively from a poison system database for all single-substance pediatric (5 years-old and younger) doxylamine ingestions for the period of 1997-2012. Data collected included age, gender, weight, reason for exposure, exact or estimated maximum dose, clinical effects and medical interventions.
Results: A total of 140 cases were identified; 74 (53%) involved males. Ages ranged 6 months to 5 years. In 30 cases (21%), the exact amount ingested was documented and ranged from 6.25-50 mg with a maximum weight-based dose of 6.2 mg/kg. In 76 cases, the estimated maximum dose ranged from 12.5 to 375 mg with a maximum weight-based dose of 37 mg/kg. All symptoms were mild and self-limiting. The only documented intervention was the administration of activated charcoal in 13 cases.
Conclusion: Unintentional isolated pediatric doxylamine ingestions did not result in significant toxicity in our 140 cases. Reported doses of up to 6.2 mg/kg resulted in only transient drowsiness and tachycardia.
Keywords: Antihistamine; Doxylamine; Pediatric; Poisoning.