Neonatal abstinence syndrome

Background

• Polysubstance combining opiates and cocaine must be considered
• Withdrawal within first 24-48 hrs --> fetal alcohol syndrome
• Withdrawal within 48-72 hrs --> heroin
• Withdrawal at 7-14 days --> methadone

Clinical Presentation

• Agitated - high-pitched cry, restlessness, tremors, hypertonia, convulsions
• Vasomotor - sweating, fever
• Respiratory - nasal congestion, persistent sneezing, RR > 60/min, nasal flaring
• Metabolic - poor feeding, vomiting, loose stools

Differential Diagnosis

• Neonatal sepsis
• Hyperthyroidism/hypothyroidism
• Hypocalcemia
• Hypoglycemia
• Vertically transmitted diseases (HepB, HepC, HIV, etc.)
• Other withdrawal (caffeine, cocaine, nicotine, amphetamines, SSRIs)

Diagnosis

• Pharmacologic treatment when 3 consecutive ≥ 8 on NAS(Finnegan scale
• Enzyme immunoassay, urine toxicology, meconium analysis
• Consider cranial US for cocaine-exposed neonates with abnormal neurologic signs

Treatment

• Supportive - swaddling to decrease sensory stimulation, frequent small feedings of 24 cal/oz formula
• Opiates when supportive measures fail
• Morphine is 1st line for infants exposed to both opiates and benzos
  • Neonatal morphine 0.4 mg/ml PO sln
    • Watch for side effect limiting dose (urinary retention)
    • Withdrawal symptoms need to be stabilized for 3-5 days before taper
    • Mother's methadone < 50 mg (or other opiate)
      • Start morphine PO sln 0.1 mg/kg q3hrs with feeds
      • Increase by 0.1 mg/kg hourly if NAS score ≥ 8, max 1 mg/kg
    • Mother's methadone > 50 mg
      • Start 0.2 mg/kg q3hrs
      • Increase by 0.2 mg/kg hourly if NAS score ≥ 8, max 1 mg/kg
  • If NPO, use preservative free morphine at 50 mcg/ml
    • Load 30 mcg/kg over 1hr, then infusion at 2 mcg/kg/hr
    • Increase by 1 mcg/kg/hr hourly until NAS < 8, max 6 mcg/kg/hr
• Benzo withdrawal treatment
  • Midazolam 0.1 mg/kg IV q3hrs or 0.3 mg/kg PO q3hrs
  • OR phenobarbital 3 mg/kg IV or PO q24hrs
• Phenobarbital for seizures OR side effect limiting morphine effects OR max morphine dose reached
  • 16 mg/kg load divided into two consecutive feedings for day 1
  • 24 hrs later, use 2-8 mg/kg/day maintenance dose

See Also

• Opioid withdrawal

Sources

• Hudak et al. Neonatal Drug Withdrawal AAP Policy. PEDIATRICS Vol. 129 No. 2 February 1, 2012, pp. e540 -e560.
• Hamdan et al. Neonatal Abstinence Syndrome. Medscape 2014. http://emedicine.medscape.com/article/978763-overview#showall.
• Klein, J. Identifying Neonatal Abstinence Syndrome (NAS) and Treatment Guidelines. University of Iowa Children's Hospital 2/11/13. http://www.uichildrens.org/uploadedFiles/UIChildrens/Health_Professionals/Iowa_Neonatology_Handbook/Pharmacology/Neonatal%20Abstinence%20Syndrome%20Treatment%20Guidelines%20Feb2013%20revision.pdf
• Perinatal Quality Collaborative of North Carolina. Best Practice Neonatal Abstinence Syndrome. Document online.