Administration of neonatal drugs – use of naloxone in infants:
Naloxone (Narcan) is an opioid antagonist which may be able to reverse the effects of Pethidine or Morphine given during labour. This is not a drug for resuscitation. For the clinical situation of a newborn with respiratory depression after maternal opiate exposure, the focus need to remain on effective ventilation and airway support for the persistently apnoeic newborn. It should only be given if, after resuscitation, the baby is pink and with a good heart rate >100 but there is poor or no respiratory effort due to opiates given to the mother prior to the birth of the baby.
The dose of Narcan is 200micrograms or if weight is available 100 micrograms/kg, given intramuscularly. Use the adult Narcan preparation of 400 micrograms /ml.
Opiates accumulate progressively in the unborn baby after administration to the mother. Naloxone 200micrograms IM given to the baby will usually reverse any opiate effect and the effect of this dose lasts up to 24 hours. However, in the neonate, the opiates require a longer time for elimination from the body (up to 48hours) and may outlast the effect of naloxone. Therefore, babies who respond to the single dose of Naloxone need observation in hospital for at least 48 hours to ensure that they do not succumb to further respiratory depression, once the effect of Naloxone wears off. Careful observations of the respiratory rate need to be made and if the baby has been delivered outside an obstetric unit, transfer to a hospital for continuing observation of the neonate should be arranged.