Phenobarbital and Clonidine as Secondary Medications for Neonatal Opioid Withdrawal Syndrome

Non-pharmacologic and pharmacologic care of the neonate with opioid withdrawal syndrome

There has been a significant paradigm shift in the management of infants with NOWS to emphasizing the role of non-pharmacologic care centered on the mother-infant dyad. By promoting bonding through rooming-in, breast-feeding and skin-to skin contact in a low stimulation environment, short and long-term outcomes have dramatically improved, resulting in reduced length of stay and need for pharmacologic treatment of the newborn. This shift in care also empowers the mother and promotes bonding and attachment, providing a solid foundation for a safe discharge. When non-pharmacological treatments are not sufficient to control the infant's withdrawal symptoms then medications can be used as an adjunct, to the minimum extent necessary and should never be used in isolation of non-pharmacological interventions. Quality improvement efforts should focus on optimizing and standardizing both non-pharmacologic and pharmacologic care to best serve this population.

Clonidine as Monotherapy for Neonatal Opioid Withdrawal Syndrome: A Randomized Trial

OBJECTIVE

We sought to determine whether clonidine, a non-opioid α-2-adrenergic agonist, would effectively treat neonatal opioid withdrawal syndrome (NOWS).

METHODS

This was an intention-to-treat randomized clinical trial. Enrollment criteria included prenatal opioid exposure, age ≤7 days, gestational age ≥35 weeks, no other medical condition, and need for pharmacotherapy. Primary outcomes were length of treatment and neurobehavioral performance.

RESULTS

A total of 1107 patients were screened for enrollment (645 ineligible, 91 parents or staff unavailable, 216 declined, 155 consented). Of 155 infants, 120 required treatment and were randomized to receive oral clonidine (n = 60) at 1 µg/kg/dose or morphine (n = 60), 0.06 mg/kg/dose, every 3 hours. Infants with no improvement had their doses increased by 25% of the initial dose every 12 to 24 hours. Those without improvement by the fourth dose increase, received adjunct therapy. Length of treatment did not differ between morphine and clonidine, with median (95% confidence interval [CI]) days, respectively, of 15 (13-17) and 17 (15-19), P = .48. More clonidine-treated infants (45%) needed adjunct therapy versus 10% in the morphine group, adjusted odds ratio (95% CI) = 8.85 (2.87-27.31). After treatment completion, the NICU Network Neurobehavioral Scales summary scores did not differ between clonidine-treated and morphine-treated infants.

CONCLUSIONS

Length of pharmacologic treatment and final neurobehavioral performance were not significantly different between the clonidine- and morphine-treated groups. Clonidine appears to be an effective non-opioid medication to treat NOWS. Future studies are needed to determine the optimal clonidine dosage for a quicker response and obviation of adjunct therapy.

Illicit Fentanyl in the Prenatal Period: A Significant Emerging Risk for Neonatal Opioid Withdrawal Syndrome

OBJECTIVE

 This study aimed to evaluate the impact of in-utero illicit fentanyl exposure on neonatal outcomes, including neonatal opioid withdrawal syndrome (NOWS), length of stay (LOS), and treatment requirements.

STUDY DESIGN

 This study was conducted from March 2020 to December 2022, and focused on neonates born to mothers with opioid use or opioid use disorder (OUD). Maternal opioid use was identified through self-report or umbilical cord tissue (UCT) testing. Severe NOWS was defined as cases requiring pharmacological treatment. Statistical analyses included univariate comparisons, logistic regression, and generalized linear models to assess the associations between fentanyl exposure and neonatal outcomes.

RESULTS

 Forty-seven percent (75/159) of infants had in-utero fentanyl exposure. Fentanyl-positive mothers were older, 31 ± 5 years, compared to non-fentanyl mothers, 29 ± 5, p = 0.01. They were also less likely to receive prenatal care (p < 0.01) and had a higher number of polysubstance used, 5 ± 1 compared to non-fentanyl mothers, 3 ± 1, p < 0.01. Overall, infants exposed to fentanyl had a higher incidence of severe NOWS (odds ratio = 5.8, 95% confidence interval [CI]: 2.49-12.95, p < 0.01) and required earlier NOWS treatment initiation, 1 ± 1 day compared to non-exposed infants 3 ± 2 days, p < 0.01. In adjusted analysis, fentanyl exposure was associated with a nearly three-fold increased risk of NOWS (Mantel-Haenszel combined relative risk = 2.98, 95% CI: 1.94-4.57). Furthermore, fentanyl exposure led to longer LOS, with a 40% increase for preterm neonates (p < 0.01) and a 63% increase for full-term neonates (p < 0.01). Additionally, there was a significant correlation between log fentanyl concentration in umbilical cord tissue and cumulative morphine dose required for NOWS treatment, p = 0.001.

CONCLUSION

 Prenatal illicit fentanyl exposure is an independent and strong risk factor for severe NOWS presentation in newborns requiring extended hospital stays.

KEY POINTS

· Illicit fentanyl is increasingly recognized as a major driver of opioid-related substance use disorders during pregnancy, often occurring alongside polysubstance use.. · Significant prenatal exposure to opioids is a well-established risk factor for neonatal opioid withdrawal syndrome. The recent rise in illicit fentanyl use has heightened these concerns.. · Both preterm and term infants are at risk for severe withdrawal symptoms following prenatal exposure to illicit fentanyl..

Advances in animal models of prenatal opioid exposure

Neonatal opioid withdrawal syndrome (NOWS) is a growing public health concern. The complexity of in utero opioid exposure in clinical studies makes it difficult to investigate underlying mechanisms that could ultimately inform early diagnosis and treatments. Clinical studies are unable to dissociate the influence of maternal polypharmacy or the environment from direct effects of in utero opioid exposure, highlighting the need for effective animal models. Early animal models of prenatal opioid exposure primarily used the prototypical opioid, morphine, and opioid exposure that was often limited to a narrow period during gestation. In recent years, the number of preclinical studies has grown rapidly. Newer models utilize both prescription and nonprescription opioids and vary the onset and duration of opioid exposure. In this review, we summarize novel prenatal opioid exposure models developed in recent years and attempt to reconcile results between studies while critically identifying gaps within the current literature.

Neonatal Abstinence Syndrome: A Review of Treatment in the Neonatal Intensive Care Unit

Background

Neonatal abstinence syndrome (NAS) is a collection of symptoms that neonates may experience following antenatal exposure to substances that induce withdrawal. Optimal management remains unknown, and there is variation in management and outcomes.

Objectives

To describe the management, length of hospitalization, and adverse events in near-term and full-term neonates with NAS for whom treatment (pharmacotherapy and/or supportive care) was initiated in the neonatal intensive care unit (NICU).

Methods

A chart review was conducted of neonates admitted to the NICU of Surrey Memorial Hospital, Surrey, British Columbia, who received treatment for NAS between September 1, 2016, and September 1, 2021.

Results

A total of 48 neonates met the inclusion criteria. Opioids represented the most frequent type of antenatal exposure. Polysubstance exposures occurred in 45 (94%) of the neonates. Morphine was given to 29 (60%) of the neonates, and phenobarbital to 6 (13%); 5 of these neonates received both medications. The average duration of morphine treatment was 14 days, and the average length of hospitalization (all patients) was 16 days. All of the neonates experienced adverse events; in particular, 9 (30%) of the 30 who received pharmacotherapy were too sedated to feed, compared with 0% of the 18 with no pharmacotherapy.

Conclusions

The common finding of polysubstance antenatal exposure, involving predominantly opioids, was associated with scheduled morphine pharmacotherapy for the majority of patients, prolonged hospitalization, and frequent adverse events. Pharmacotherapy for NAS was associated with levels of sedation that interfered with feeding in neonates.

Prenatal methadone exposure selectively alters protein expression in primary motor cortex: Implications for synaptic function

As problematic opioid use has reached epidemic levels over the past 2 decades, the annual prevalence of opioid use disorder (OUD) in pregnant women has also increased 333%. Yet, how opioids affect the developing brain of offspring from mothers experiencing OUD remains understudied and not fully understood. Animal models of prenatal opioid exposure have discovered many deficits in the offspring of prenatal opioid exposed mothers, such as delays in the development of sensorimotor function and long-term locomotive hyperactivity. In attempt to further understand these deficits and link them with protein changes driven by prenatal opioid exposure, we used a mouse model of prenatal methadone exposure (PME) and preformed an unbiased multi-omic analysis across many sensoriomotor brain regions known to interact with opioid exposure. The effects of PME exposure on the primary motor cortex (M1), primary somatosensory cortex (S1), the dorsomedial striatum (DMS), and dorsolateral striatum (DLS) were assessed using quantitative proteomics and phosphoproteomics. PME drove many changes in protein and phosphopeptide abundance across all brain regions sampled. Gene and gene ontology enrichments were used to assess how protein and phosphopeptide changes in each brain region were altered. Our findings showed that M1 was uniquely affected by PME in comparison to other brain regions. PME uniquely drove changes in M1 glutamatergic synapses and synaptic function. Immunohistochemical analysis also identified anatomical differences in M1 for upregulating the density of glutamatergic and downregulating the density of GABAergic synapses due to PME. Lastly, comparisons between M1 and non-M1 multi-omics revealed conserved brain wide changes in phosphopeptides associated with synaptic activity and assembly, but only specific protein changes in synapse activity and assembly were represented in M1. Together, our studies show that lasting changes in synaptic function driven by PME are largely represented by protein and anatomical changes in M1, which may serve as a starting point for future experimental and translational interventions that aim to reverse the adverse effects of PME on offspring.

Future Newborns with Opioid-Induced Neonatal Abstinence Syndrome (NAS) Could Be Assessed with the Genetic Addiction Risk Severity (GARS) Test and Potentially Treated Using Precision Amino-Acid Enkephalinase Inhibition Therapy (KB220) as a Frontline Modality Instead of Potent Opioids

In this nonsystematic review and opinion, including articles primarily selected from PubMed, we examine the pharmacological and nonpharmacological treatments of neonatal abstinence syndrome (NAS) in order to craft a reasonable opinion to help forge a paradigm shift in the treatment and prevention of primarily opioid-induced NAS. Newborns of individuals who use illicit and licit substances during pregnancy are at risk for withdrawal, also known as NAS. In the US, the reported prevalence of NAS has increased from 4.0 per 1000 hospital births in 2010 to 7.3 per 1000 hospital births in 2017, which is an 82% increase. The management of NAS is varied and involves a combination of nonpharmacologic and pharmacologic therapy. The preferred first-line pharmacological treatment for NAS is opioid therapy, specifically morphine, and the goal is the short-term improvement in NAS symptomatology. Nonpharmacological therapies are individualized and typically focus on general care measures, the newborn-parent/caregiver relationship, the environment, and feeding. When used appropriately, nonpharmacologic therapies can help newborns with NAS avoid or reduce the amount of pharmacologic therapy required and the length of hospitalization. In addition, genetic polymorphisms of the catechol-o-methyltransferase (COMT) and mu-opioid receptor (OPRM1) genes appear to affect the length of stay and the need for pharmacotherapy in newborns with prenatal opioid exposure. Therefore, based on this extensive literature and additional research, this team of coauthors suggests that, in the future, in addition to the current nonpharmacological therapies, patients with opioid-induced NAS should undergo genetic assessment (i.e., the genetic addiction risk severity (GARS) test), which can subsequently be used to guide DNA-directed precision amino-acid enkephalinase inhibition (KB220) therapy as a frontline modality instead of potent opioids.

Comparison of Two Morphine Dosing Strategies in the Management of Neonatal Abstinence Syndrome

OBJECTIVE

The incidence of neonatal abstinence syndrome (NAS) has increased in recent years. Treatment approaches usually involve opioid replacement; however, the optimal treatment strategy is unknown. This study sought to determine the impact of weight- and symptom-based morphine dosing strategies on LOS and medication exposure in patients with NAS.

METHODS

A retrospective review was conducted from May 2015 to June 2017 at 2 NICUs within a health-system using different dosing approaches for NAS. Data were compared using Fisher exact tests for categorical data and t tests and Wilcoxon ranked sums for continuous data.

RESULTS

Baseline demographics were well-matched except for postmenstrual age at morphine initiation (p = 0.04). The weight-based group had a larger initial morphine dose (p &lt; 0.001) and fewer number of steps to maximum morphine dose (p = 0.009). There were no differences between groups in LOS, number of dose adjustments, doses administered, weaning steps, maximum dose, or need to re-escalate dosing. There was also no difference between the first 3 modified Finnegan scores (MFS) after transferring patients to a neonatology service. Neonates with symptom-based dosing had a higher maximum MFS (p = 0.024). Neonates in the symptom-based group required adjunct therapy more often (p &lt; 0.0001).

CONCLUSIONS

Data indicate the dosing strategy impacts number of steps to reach maximum dose and need for adjunctive therapy. Weight-based dosing may decrease the number of steps required to reach the morphine maximum dose and the need for adjunctive therapy by controlling NAS symptoms earlier.

Use of Phenobarbital to Treat Neonatal Abstinence Syndrome From Exposure to Single vs. Multiple Substances

Drug use in pregnancy is a major public health issue. Intrauterine exposure to opioids alone or in addition to other substances may lead to neonatal abstinence syndrome (NAS). Little consensus exists on optimal therapy, especially for those exposed to multiple drugs. We aim to determine whether the use of opioids alone vs. in combination with phenobarbital will affect short-term neonatal outcomes. This retrospective review of infants admitted to the neonatal intensive care unit (NICU) included newborns ≥35 weeks of gestation exposed to opioids, or multiple substances including opioids, in utero. Treatment with opioids alone, and addition of phenobarbital as initial therapy vs. rescue, was evaluated. Out of 182 newborns, 54 (30%) were exposed to methadone alone vs. 128 (70%) to multiple drugs. Length of stay (LOS) in the hospital was not significantly affected (p = 0.684) by single vs. multiple drug exposure in utero. Treatment of NAS with opioid alone resulted in significantly shorter LOS (27 days), as compared to those treated with opioid and phenobarbital (45 days, p < 0.001). LOS was further prolonged in those treated with phenobarbital as a "rescue" medication in addition to an opioid (49 days, p < 0.0001). There was a significant increase in LOS and duration of opioid treatment for all infants treated with phenobarbital, both in those exposed to opioids alone, and to multiple substances in utero.