A schematic illustration of the mechanism of opioid withdrawal in neonates. Lack of opiates in a chronically stimulated state leads to the upregulation of cyclic adenosine monophosphate, which leads to increased production and release of various neurotransmitters through complex mechanisms. Withdrawal is the result of increased production of noradrenaline, acetyl choline, corticotrophin, and other substances, as well as the decreased production of serotonin and dopamine. These mechanisms may be able to explain most of the signs that are characteristically seen in neonates with abstinence syndrome.
A management plan for NAS in neonates. Medications are to be initiated, increased, decreased, or discontinued depending on the Finnegan score. Morphine can be initiated at a higher dose if scores are high; for example, if the scores are 17 to 20, morphine can be started at 0.12 mg per dose, and if the scores are ≥25, morphine can be initiated at 0.20 mg per dose.49 Morphine dose can also be escalated by >10% for higher scores.21 Methadone can be substituted for morphine for opioid withdrawal. Cardiopulmonary monitoring of the infant is preferred during the acute stage.