Objective To examine the effect of a multifaceted educational intervention on the incidence of medication preparation and administration errors in a neonatal intensive care unit (NICU).

Design Prospective study with a preintervention and postintervention measurement using direct observation.

Setting NICU in a tertiary hospital in the Netherlands.

Intervention A multifaceted educational intervention including teaching and self-study.

Main outcome measures The incidence of medication preparation and administration errors. Clinical importance was assessed by three experts.

Results The incidence of errors decreased from 49% (43–54%) (151 medications with one or more errors of 311 observations) to 31% (87 of 284) (25–36%). Preintervention, 0.3% (0–2%) medications contained severe errors, 26% (21–31%) moderate and 23% (18–28%) minor errors; postintervention, none 0% (0–2%) was severe, 23% (18–28%) moderate and 8% (5–12%) minor. A generalised estimating equations analysis provided an OR of 0.49 (0.29–0.84) for period (p=0.032), (route of administration (p=0.001), observer within period (p=0.036)).

Conclusions The multifaceted educational intervention seemed to have contributed to a significant reduction of the preparation and administration error rate, but other measures are needed to improve medication safety further.