Plasma concentrations of atropine after rectal administration

The rectal administration of the premedication for children is often preferred in order to minimise discomfort. The appropriate dose of atropine when rectally administered is poorly documented. In this study six children weighing between 7.5 and 41 kg were given 0.02 mg atropine sulphate/kg rectally and four children were given the same doses intramuscularly. Plasma concentrations of atropine were analysed at several intervals after administration by a modified mass fragmentographic method accurate to 0.1 ng/ml. Peak plasma concentration of atropine, reached after 15 minutes, was 0.7 ng/ml, compared with 2.40 ng/ml reached after 5 minutes for the intramuscular route. The relation between intramuscular and rectal peak concentration was 3.2:1.