EpiPen Jr versus EpiPen in young children weighing 15 to 30 kg at risk for anaphylaxis.

BACKGROUND

The EpiPen Jr (0.15 mg) and EpiPen (0.3 mg) auto-injectors, widely prescribed for the out-of-hospital treatment of anaphylaxis, have not been compared prospectively in young children.

OBJECTIVE

The purpose of this investigation was to study the rate and extent of epinephrine absorption after use of the EpiPen Jr and the EpiPen in children weighing 15 to 30 kg.

METHODS

In a randomized, double-blinded, parallel-group pilot study, children at risk for anaphylaxis self-injected epinephrine using either an EpiPen Jr or an EpiPen with the aid of a physician. Plasma epinephrine concentrations, blood glucose, blood pressure, heart rate, and adverse effects were monitored before and for 180 minutes after the injection.

RESULTS

Children (age [mean +/- SEM], 5.4 +/- 0.4 years; weight [mean +/- SEM], 18.0 +/- 0.6 kg) who injected epinephrine with an EpiPen Jr achieved a maximum plasma concentration (mean +/- SEM) of 2037 +/- 541 pg/mL at 16 +/- 3 minutes. Children (6.6 +/- 0.5 years; 25.4 +/- 1.5 kg) who injected epinephrine with an EpiPen achieved a maximum plasma concentration of 2289 +/- 405 pg/mL at 15 +/- 3 minutes. Mean systolic blood pressure 30 minutes after epinephrine injection was significantly higher with the EpiPen than with the EpiPen Jr. After injection with the EpiPen Jr, every child experienced transient pallor; some also experienced tremor and anxiety. After injection with the EpiPen, every child developed transient pallor, tremor, anxiety, and palpitations or other cardiovascular effects; some also developed headache and nausea.

CONCLUSIONS

Epinephrine injection with the EpiPen rather than the EpiPen Jr raised the systolic blood pressure significantly but also caused more adverse effects. The beneficial pharmacologic effects and the adverse pharmacologic effects of epinephrine cannot be dissociated. For the out-of-hospital treatment of anaphylaxis, additional premeasured, fixed doses of epinephrine would facilitate more precise dosing in young children.