Thank you for your recent inquiry.
The fact of the matter is that the proper dose of epinephrine in either a child or an adult is totally unknown. The 0.01 mg per kg dosage is purely empirical. There are no pharmacokinetic, pharmacodynamic, or outcome studies of the dose response curve to epinephrine either in children or adults. Adverse events due to epinephrine overdoses have been recorded periodically in the literature, but they are more commonly reported in adults than children, and are due to errors of administration using a syringe and a multidose vial rather than an overdose to automatic injectors. In actuality children usually tolerate epinephrine quite well. It is better in most instances to prescribe an auto-injector than a syringe with a multidose vial in the instance you describe.
For more reading on this issue, I refer you to a recent editorial in the "Annals of Allergy, Asthma, and Immunology" (1).
Thank you again for your inquiry and we hope this response is helpful to you.
1. Lieberman P. The 10 second rule and other myths about epinephrine and autoinjectors. Annals of Allergy, Asthma, and Immunology 2011 (September); 107(3):189-190.
Phil Lieberman, M.D.