Drug administration to neonates is frequently and inversely correlated to gestational age and birth weight. Neonates are exposed to different therapeutic classes, reflecting scientific advances in neonatology. In Brazil, the percentage of drugs with neonate-specific labelling information is low. Consequently, there is an evident need for efforts to guarantee effective and safe pharmacotherapy for neonates.

This study was designed to investigate the use of off-label and unlicensed drugs in a Neonatal Care Unit (NCU) and to compare the frequency of use of off-label drugs according to the drug regulatory agencies in Brazil (Agência Nacional de Vigilância Sanitária-ANVISA) and the United States Food and Drug Administration (FDA). A prospective observational study was carried out in the NCU. Prescriptions were classified as off-label and unlicensed using both ANVISA and FDA criteria. A total of 157 newborns and 1187 prescriptions were analyzed. The most prescribed drug was fentanyl (9.3%), followed by multivitamin (8.4%) and gentamicin (7.9%). According to ANVISA criteria, there were 665 (56.0%) offlabel prescriptions and 86 (7.2%) unlicensed prescriptions and 95.5% of newborns received at least one drug off-label. By contrast, according to FDA criteria, there were 592 (49.9%) off-label prescriptions and 84 (7.1%) unlicensed prescriptions, and 72.0% of newborns received at least one drug off-label. The offlabel use of drugs registered by ANVISA differed significantly from that of drugs registered by the FDA. There was a high frequency of off-label and unlicensed drug use in the investigated NCU, and there was an inverse relationship between off-label and unlicensed usage and the gestational age of the newborns.