Clinical pharmacokinetics of penicillins in the neonate: a review of the literature

Background

Sepsis is common in neonates and a major cause of morbidity and mortality. Sixty percent of preterm neonates receive at least one antibiotic during the first week of life, with penicillins being the most frequently administered antibiotics. The clearance (Cl), serum half-life (t_½) and volume of distribution (Vd) of penicillins are different in the neonate than in the adult. As such, the pharmacokinetics of penicillins need be studied in neonates in order to optimise therapy in this age class with these drugs.

Objectives

The aim of this study was to review the published data on the pharmacokinetics of penicillins in the neonate in order to provide a critical analysis of the literature and, consequently, a useful tool in the hands of the physician.

Methods

The bibliographic search was performed electronically using the PubMed and EMBASE databases as search engines. An initial search was performed with the keywords “pharmacokinetics”, “penicillins” and “neonates”. Secondly, other searches were performed using the keywords “pharmacokinetics” and “neonates”, followed by the name of a single antibiotic. The search included articles up to 2007.

Results

There have been few pharmacokinetic studies on the use of penicillins in neonates. The results from those few studies that have been carried out suggest that the Cl is reduced and t_½ prolonged in the neonate as compared with the more mature infant. There is little variation in Vd during the first week of life. In the premature neonate, Cl is reduced compared to the full-term infant. As postnatal age proceeds, the Cl of penicillins increases.

Conclusions

More pharmacokinetic studies are required to provide a sound scientific basis for planning a dosage regimen with penicillins in the neonate.