Drug distribution, metabolism and elimination may be altered in neonates; this varies over time and is of most concern during the first month of life
Increased volume of distribution will reduce serum concentrations of water soluble antimicrobials, often necessitating higher doses
Decreased metabolism and elimination will prolong the half life of many drugs, potentially required prolonged dosing intervals; toxicity risks may be increased
In the first days of life, oral absorption may be markedly increased; drugs that are normally poorly absorbed maybe well absorbed, potentially causing toxicity (e.g. neomycin)
Nursing limits the ability to give medications on an empty stomach and creates the potential for binding of drugs to milk components