BACKGROUND: Epinephrine is life-saving in the treatment of anaphylaxis. A limited number of fixed-dose epinephrine formulations are available for out-of-hospital treatment of this disorder. OBJECTIVE: To examine dispensing patterns for epinephrine formulations over 4 consecutive years in a population of 279,638 infants, children, and adolescents (from birth up to but not including the 17th birthday). METHODS: We used the Drug Programs Information Network, an administrative claims database for prescriptions dispensed in ambulatory care settings, developed from real-time computer links with retail pharmacies in the province of Manitoba, Canada. We studied the specific epinephrine formulation dispensed and the precise age of the infant or child at the time it was dispensed. RESULTS: Epinephrine formulations were dispensed for 1.2% of the pediatric population (3,340 children). Boys comprised 59.5% of the recipients. Of all epinephrine formulations, 38.6% were dispensed as EpiPen Jr (0.15 mg), and 57.4% were dispensed as EpiPen (0.3 mg). EpiPen Jr was dispensed for patients ranging in age from 2 months to 16 years, 10 months, inclusive. EpiPen was dispensed for patients ranging in age from 1 year, 8 months to 16 years, 11 months, inclusive. During the 4 years studied, a subgroup of children transitioned from EpiPen Jr to EpiPen auto-injectors at a mean age of 6 years, 6 months +/- 2 years, 8 months (range 1 year, 10 months to 16 years, 11 months). CONCLUSIONS: Both EpiPen Jr and EpiPen auto-injectors were dispensed over almost the entire age range of the pediatric population. Physicians should consider a child's age more carefully when prescribing these auto-injectors. Additional concentrations of epinephrine are needed in these fixed-dose formulations.