1 The Departments of Pediatrics and Medicine, University of Washington School of Medicine, Seattle, Washington and the Hektoen Research Institute of the Cook County Hospital, Chicago, Illinois
Serum levels of methicillin and ampicillin are reported in 82 term and premature infants in groups of increasing postnatal age. During the first day of life, term infants showed high and sustained serum levels following a single injection of either agent. When methicillin was given to groups of term infants beyond the first day of life, rapid changes in excretion rate occurred with increasing postnatal age. Premature infants showed similar changes in excretion rate with age, with higher levels at any given age than the term infants. These findings are discussed in relation to neonatal renal and hepatic function and suggestions are made regarding clinical use of these drugs. A brief description is given of a highly accurate bio-assay method for the penicillins which can be adapted for most antibiotics and is suitable for investigational and clinical use in small infants.
Submitted on May 20, 1966