1 The Departments of Pediatrics and Pharmacology, University of Illinois College of Medicine, Chicago.
The susceptibility of apparently healthy children of all age groups to atropine by oral and subcutaneous administration was studied in carefully controlled experiments on 129 children. The minimal effective dose (MED) of atropine was determined by its effect in suppressing sialorrhea elicited either mechanically by chewing gum and/or pharmacologically by subcutaneous injection of methacholine.
Variations in individual susceptibility to atropine are large in all age groups and independent of the route of administration (oral, hypodermic.)
The average MED/kg. body weight following oral administration is somewhat smaller in infants of 1 to 12 months and children from 12 to 36 months (0.16 and 0.14 mg./kg., respectively) than in older children in the age groups of 3 to 6 years and 6 to 12 years (0.22 and 0.20 mg./kg., respectively). Comparable results are obtained by hypodermic administration.
The ratio between the MED by mouth and the MED by hypodermic injection is approximately 3:1 in all age groups.
The determination of the susceptibility of children of various ages of atropine fails to adduce evidence supporting the assumption of an increased resistance to atropine or of a physiologic vagotonia in infants.
The relation of the MED of atropine in apparently healthy children to the doses recommended in pediatric therapy is discussed. The calculation of the dosage of atropine by body weight is recommended.
Submitted on November 12, 1949