During the treatment with sulfapyridine of pneumonia1 and other conditions in children we have accumulated considerable data concerning the concentration of the drug in the blood. Although we agree with Long and his associates2 that the level in the blood is the most satisfactory guide to dosage for a given patient, we realize that it is necessary to have some program for determining the preliminary dosage for patients of various ages and sizes. Because it is simple, convenient and in accordance with accurate pharmacologic procedure, we have based this dosage on the body weight of the patient. The data presented show the concentrations of the drug in the blood that were obtained with such dosage.
METHODS AND MATERIAL
Six hundred and fourteen determinations of the levels of free sulfapyridine were made on the blood of 126 children, averaging four and eight-tenths determinations per patient. Sixty-seven of these children