What is the role of drug treatment for neonatal abstinence syndrome (NAS)?

Updated: Dec 20, 2017
  • Author: Ashraf H Hamdan, MD, MBBCh, MSc, MRCP, FAAP; Chief Editor: Santina A Zanelli, MD  more...
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Pharmacotherapy for infants with more severe expression of neonatal abstinence syndrome is necessary to allow them to feed, sleep, gain weight, and interact with caregivers. Approximately 30-91% of infants who exhibit signs of NAS receive pharmacological treatment. The limited available evidence from controlled trials of neonatal opioid withdrawal supports the use of oral morphine solution and methadone when pharmacologic treatment is indicated. Growing evidence suggests that oral clonidine is also effective either as a primary or adjunctive therapy, but further prospective trials are warranted. [40]

There is evidence that, compared with oral methodone treatment, oral morphine sulfate therapy for NAS reduces the length of stay in the hospital and neonatal intensive care unit (NICU), treatment duration, maximum opioid requirements, and total cost. [69]  Another study published in the same year showed that methadone had a shorter length of neonatal withdrawal treatment compared to that of morphine. [70]

Treatment with sublingual buprenorphine for NAS appears to be associated with a shorter duration of opioid therapy and hospitalization compared with oral methadone therapy. [71, 72, 73]  Studies comparing buprenorphine to morphine have shown shorter duration of treatment and shorter hospital stay in infants treated with buprenorphine. Both groups had similar rates of side efects. However, these studies were single institution including small sample size. [74]  More recent larger studies have demonstrated comparable findings. [73]   

There is significant variability in the severity of NAS due to in utero opioid exposure. Studies have shown that single nucleotide polymorphisms (SNPs) in opioid receptors and the prepronociceptin (PNOC) genes are associated with NAS severity. [75] Another study showed that among infants with NAS, variants in the μ-opioid receptor (OPRM1) and catechol-o-methyltransferase (COMT) genes were associated with a shorter length of hospital stay and less need for treatment. [76] However, the investigators suggested that further studies are needed in a larger sample.

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