In neonates, the extracellular fluid (ECF) constitutes up to 45% of total body weight, requiring relatively larger doses of certain antibiotics (eg, aminoglycosides) compared with adults. Lower serum albumin concentrations in premature infants Premature Infants An infant born before 37 weeks gestation is considered premature. Prematurity is defined by the gestational age at which infants are born. Previously, any infant weighing < 2.5 kg was termed... read more may reduce antibiotic protein binding. Drugs that displace bilirubin from albumin (eg, sulfonamides, ceftriaxone) increase the risk of kernicterus Kernicterus Kernicterus is brain damage caused by unconjugated bilirubin deposition in basal ganglia and brain stem nuclei. Normally, bilirubin bound to serum albumin stays in the intravascular space. However... read more .
Absence or deficiency of certain enzymes in neonates may prolong the half-life of certain antibiotics (eg, chloramphenicol) and increase the risk of toxicity. Changes in glomerular filtration rate and renal tubular secretion during the first month of life necessitate dosing changes for renally excreted drugs (eg, penicillins, aminoglycosides, vancomycin).
(See also Overview of Neonatal Infections Overview of Neonatal Infections Neonatal infection can be acquired In utero transplacentally or through ruptured membranes In the birth canal during delivery (intrapartum) From external sources after birth (postpartum) Common... read more .)