15 The relation between the serum trough concentration of paracetamol and pain reduction in preterm and term neonates: a retrospective observational study

Measuring concentrations of paracetamol could be a strategy to optimize the treatment of pain. It is not known if the serum trough concentration of paracetamol at steady state conditions could predict a decrease in pain scores in preterm and term neonates. Low trough concentration can result in inadequate pain relief. The aim of this study was to determine the association between the serum trough concentration of paracetamol and pain reduction in preterm and term neonates. In this retrospective observational study a hospital database was used to select neonates who were treated with at least 48 hours of paracetamol intravenously or rectally. Linear regression was performed to determine if serum trough concentration of paracetamol at steady state conditions was a predictor for pain reduction. Pain reduction was defined as the difference between COMFORTneo scores before administration and after the fifth administration of paracetamol. 21 neonates were included for determining the association between serum trough concentration paracetamol and pain reduction. The median (IQR) of serum trough concentration of paracetamol after the fifth dose was 4.5 mg/L (2.7–8.5 mg/L). At steady state conditions the serum trough concentration of paracetamol was not a significant predictor of pain reduction in preterm and term neonates (p = 0.79 for preterm neonates and p = 0.49 for term neonates). No association was found between the serum trough concentration of paracetamol at steady state conditions and pain reduction in preterm and term neonates. The absence of a significant association could be due to inadequate trough concentrations paracetamol. Further research is needed to investigate the association between serum trough concentrations paracetamol of ≥ 10 mg/L and pain reduction.