Neonatal Abstenence Syndrome

Neonatal abstinence syndrome usually presents as central nervous system, autonomic nervous system and gastrointestinal disturbances. The earliest manifestations are irritability, tremors, a high-pitched cry, difficulty feeding and diarrhea. These symptoms can be evaluated objectively and semi-quantitatively by using one of the available assessment scales, such as the Finnegan Scoring System. 16 Other, shorter scoring systems include the Lipsitz 24 and the Ostrea 25 methods. The first signs of NAS usually begin when the infant?s serum methadone level declines to about 0.06ug /ml or less. 23. The metabolism of methadone varies among neonates, but the half-life averages approximately 24 hours in the term neonate, counting back from the last maternal dose. Therefore, the longer the interval between the last maternal dose and delivery of the infant, the earlier one would anticipate signs of withdrawal to appear in the infant. 23

Therapy for the Methadone-dependent Infant

Approach to therapy for the methadone-dependent infant is twofold. Supportive measures such as a low light, low noise environment, secure swaddling, gentle handling and holding, and frequent, small feedings are helpful. Hyperphagia, or increased feeding, is common in these infants, due to their increased metabolic rate. 26 Rocking beds may cause over-stimulation of these infants, and are not usually recommended. Further research is needed in this area. 27 Pharmacotherapy in the past has included opiates, barbiturates, 28 tranquilizers, clonidine, 29 morphine sulfate or methadone itself. The American Academy of Pediatrics recommends that the same class of drug be used for withdrawal therapy as that which is causing the withdrawal. 17 Thus, for methadone withdrawal, an opiate should be used, with the dosage carefully calculated according to the infant's weight. The only FDA approved drug for opiate withdrawal is methadone. 17

Clinical Observations

In the nursery at The University Hospital of Cincinnati, previously developed morphine and methadone treatment protocols have been implemented (Tables 1 and 2). Six infants withdrawing from intrauterine exposure to methadone during pregnancy were alternately treated with either oral morphine or methadone. The goal of therapy was to keep the infants relatively comfortable, with average daily abstinence scores below 8 points.

Morphine sulfate was given to three babies on the first day of life. The initial doses were 0.08 mg/Kg/dose, given orally every 4 hours. These were increased to 0.1mg/Kg/dose to control symptoms, then tapered gradually according to protocol as tolerated by the infant. The lengths of stay for the morphine-treated babies were 21, 31and 17 days, re one withdrawal spectively. These infants were moderately symptomatic, with average daily abstinence scores ranging from 5.0 to 9.5 throughout their hospitalizations.

The other three infants were treated with methadone, 0.1 mg/Kg/dose, given orally when the abstinence scores exceeded 8 points on days 3-4 of life. The doses were decreased gradually and the intervals between doses were lengthened according to protocol as tolerated by the infants. Those who were treated with methadone had average daily abstinence scores ranging from 3 to 8 during their hospitalizations, and their lengths of stay were 14, 20 and 10 days, respectively. The infant who stayed only 10 days was fed pumped breast milk, at the mother's request, in addition to formula, beginning on day 3 of life. After starting the methadone taper, average daily abstinence scores ranged from 3.0 to 7.7. From these six babies, it appeared that the methadone-treated babies were more comfortable and could be discharged from the hospital sooner than those treated with morphine. It also seemed possible that breast milk might help alleviate symptoms and might further decrease the length of their hospital stay.