Overdoses of pethidine given to two preterm neonates.

This paper reports two mechanically ventilated preterm babies who received overdoses of pethidine in the neonatal period. One of the neonates (gestational age 26 weeks, birthweight 1040 g) received repeated appropriate doses, which resulted in central nervous system irritability and convulsion due to accumulation of the drug and its metabolite, norpethidine. The other neonate (gestational age 27 weeks, birthweight 980 g) received a major (10-fold) overdose with little clinical effect. These two cases indicate notable individual variability in the responses of babies to pethidine. This is typical of other opioids, too. Therefore, the dosing of opioids to neonates should be titrated individually, and the patients should be observed carefully.