Quantifying antibiotic use in paediatrics: a proposal for neonatal DDDs

The defined daily dose (DDD) as defined by the World Health Organization (WHO) has been the most frequently used unit of measurement to measure antibiotic use. However, measuring antibiotic use in paediatrics is a problem as the WHO DDD methodology is not applicable in children (aged >1 month) due to the large variation in body weight within this population. Based on the narrow range of body weights in the neonatal population, we therefore aimed to develop a set of neonatal DDDs for antibiotics. Eight well-respected (inter)national sources for dosage recommendations of antibiotics in children and neonates were consulted for the assumed maintenance dose of the ten most frequently used antibiotics in neonatal intensive care units in its main indication for neonates. A set of neonatal DDDs for ten commonly used antibiotics in neonates based on an assumed neonatal weight of 2 kg was proposed. Primarily in children DDDs are not applicable to quantify antibiotic use since there is large variation in body weight. In the neonatal population, however, based on its narrow range of body weights and when access to patient level data is not available, neonatal DDDs can be used as a unit of measurement.