Revised dose schema of sublingual buprenorphine in the treatment of the neonatal opioid abstinence syndrome

Buprenorphine vs. morphine: impact on neonatal opioid withdrawal syndrome (NOWS) outcomes in a single center retrospective study

OBJECTIVES

To compare clinical outcomes for infants with neonatal opioid withdrawal syndrome (NOWS) treated with buprenorphine or morphine.

STUDY DESIGN

Retrospective study of infants born ≥35 weeks' gestation and admitted to the NICU for NOWS treatment between 2011 and 2022. Length of treatment, length of stay in the hospital, and the need for secondary medications were compared between buprenorphine and morphine treated neonates. Multiple regression analysis was performed, adjusting for baseline differences and confounders.

RESULTS

417 neonates were treated with morphine and 232 with buprenorphine. The buprenorphine group had shorter treatment days [-10.8 days; 95% CI: -8.08 to -13.53] and shorter hospital stay [-11.8 days; 95% CI: -8.83 to -14.78]. The buprenorphine group was no more likely to receive phenobarbital or clonidine (26% vs. 29%).

CONCLUSION

In this large single-center study, buprenorphine was associated with shorter lengths of treatment and hospital stay in the treatment of NOWS compared to morphine.

Current management of neonatal abstinence syndrome: a survey of practice in the UK and Ireland

OBJECTIVE

To study the current management practices of neonatal abstinence syndrome (NAS) throughout the UK and Ireland and identify changes in practice from the most recent survey in 2008.

DESIGN

Postal questionnaire to a consultant paediatrician or neonatologist in all 215 neonatal units in the UK and Ireland in January 2020.

RESULTS

Response rate was 62%. An objective scoring tool was used in 97% of units and the Finnegan score was favoured by 70%. Morphine sulfate use as first line for the treatment of opiate withdrawal was almost universal and 70% used a dose of 40 µg/kg every 4 hours (240 µg/kg/day). Phenobarbitone administration as a second-line agent for opiate withdrawal increased to 61% of units with significant reductions in chloral hydrate and chlorpromazine use compared with the previous survey. Morphine sulfate and phenobarbitone remain the preferred first-line and second-line agents, respectively, for polysubstance withdrawal. There was a significant increase in chlorpromazine use as first line for polydrug withdrawal (1.5-14.2%). The practice of units discharging infants' home on medication increased to 46% from 29%. All units now permit breastfeeding in mothers taking methadone, compared with 81% previously.

CONCLUSION AND RELEVANCE

Compared with the previous survey, improvements in evidence-based practices were noted, highlighting the benefits of this type of research. Nonetheless, significant variation still exists in some aspects of the management of NAS. Post-discharge follow-up varies widely, with particular deficits in ophthalmology follow-up.

Buprenorphine reduces somatic withdrawal in a mouse model of early-life morphine exposure

The rising prevalence of early-life opioid exposure has become a pressing public health issue in the U.S. Neonates exposed to opioids in utero are at risk of experiencing a constellation of postpartum withdrawal symptoms commonly referred to as neonatal opioid withdrawal syndrome (NOWS). Buprenorphine (BPN), a partial agonist at the mu-opioid receptor (MOR) and antagonist at the kappa-opioid receptor (KOR), is currently approved to treat opioid use disorder in adult populations. Recent research suggests that BPN may also be effective in reducing withdrawal symptoms in neonates who were exposed to opioids in utero. We sought to determine whether BPN attenuates somatic withdrawal in a mouse model of NOWS. Our findings indicate that the administration of morphine (10mg/kg, s.c.) from postnatal day (PND) 1-14 results in increased somatic symptoms upon naloxone-precipitated (1mg/kg, s.c.) withdrawal. Co-administration of BPN (0.3mg/kg, s.c.) from PND 12-14 attenuated symptoms in morphine-treated mice. On PND 15, 24h following naloxone-precipitated withdrawal, a subset of mice was examined for thermal sensitivity in the hot plate test. BPN treatment significantly increased response latency in morphine-exposed mice. Lastly, neonatal morphine exposure elevated mRNA expression of KOR, and reduced mRNA expression of corticotropin-releasing hormone (CRH) in the periaqueductal gray when measured on PND 14. Altogether, this data provides support for the therapeutic effects of acute low-dose buprenorphine treatment in a mouse model of neonatal opioid exposure and withdrawal.

Intrauterine and Neonatal Exposure to Opioids: Toxicological, Clinical, and Medico-Legal Issues

Opioids have a rapid transplacental passage (i.e., less than 60 min); furthermore, symptoms characterize the maternal and fetal withdrawal syndrome. Opioid withdrawal significantly impacts the fetus, inducing worse outcomes and a risk of mortality. Moreover, neonatal abstinence syndrome (NAS) follows the delivery, lasts up to 10 weeks, and requires intensive management. Therefore, the prevention and adequate management of NAS are relevant public health issues. This review aims to summarize the most updated evidence in the literature regarding toxicological, clinical, and forensic issues of intrauterine exposure to opioids to provide a multidisciplinary, evidence-based approach for managing such issues. Further research is required to standardize testing and to better understand the distribution of opioid derivatives in each specimen type, as well as the clinically relevant cutoff concentrations in quantitative testing results. A multidisciplinary approach is required, with obstetricians, pediatricians, nurses, forensic doctors and toxicologists, social workers, addiction specialists, and politicians all working together to implement social welfare and social services for the baby when needed. The healthcare system should encourage multidisciplinary activity in this field and direct suspected maternal and neonatal opioid intoxication cases to local referral centers.

Neonatal opioid withdrawal syndrome: a review of the science and a look toward the use of buprenorphine for affected infants

Neonates born to mothers taking opioids during pregnancy are at risk for neonatal opioid withdrawal syndrome (NOWS), for which there is no recognized standard approach to care. Nonpharmacologic treatment is typically used as a first-line approach for management, and pharmacologic treatment is added when clinical signs are not responding to nonpharmacologic measures alone. Although morphine and methadone are the most commonly used pharmacotherapies for NOWS, buprenorphine has emerged as a treatment option based on its pharmacologic profile and results from initial single site clinical trials. The objective of this report is to provide an overview of NOWS including a summary of ongoing work in the field and to review the state of the science, knowledge gaps, and practical considerations specific to the use of buprenorphine for the treatment of NOWS as discussed by a panel of experts during a virtual workshop hosted by the National Institutes of Health.

Opioid treatment for opioid withdrawal in newborn infants

BACKGROUND

Neonatal abstinence syndrome (NAS) due to opioid withdrawal may result in disruption of the mother-infant relationship, sleep-wake abnormalities, feeding difficulties, weight loss, seizures and neurodevelopmental problems.

OBJECTIVES

To assess the effectiveness and safety of using an opioid for treatment of NAS due to withdrawal from opioids in newborn infants.

SEARCH METHODS

We ran an updated search on 17 September 2020 in CENTRAL via Cochrane Register of Studies Web and MEDLINE via Ovid. We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for eligible trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), quasi- and cluster-RCTs which enrolled infants born to mothers with opioid dependence and who were experiencing NAS requiring treatment with an opioid.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trial eligibility and risk of bias, and independently extracted data. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included 16 trials (1110 infants) with NAS secondary to maternal opioid use in pregnancy. Seven studies at low risk of bias were included in sensitivity analysis. Opioid versus no treatment / usual care: a single trial (80 infants) of morphine and supportive care versus supportive care alone reported no difference in treatment failure (risk ratio (RR) 1.29, 95% confidence interval (CI) 0.41 to 4.07; very low certainty evidence). No infant had a seizure. The trial did not report mortality, neurodevelopmental disability and adverse events. Morphine increased days hospitalisation (mean difference (MD) 15.00, 95% CI 8.86 to 21.14; very low certainty evidence) and treatment (MD 12.50, 95% CI 7.52 to 17.48; very low certainty evidence), but decreased days to regain birthweight (MD -2.80, 95% CI -5.33 to -0.27) and duration (minutes) of supportive care each day (MD -197.20, 95% CI -274.15 to -120.25). Morphine versus methadone: there was no difference in treatment failure (RR 1.59, 95% CI 0.95 to 2.67; 2 studies, 147 infants; low certainty evidence). Seizures, neonatal or infant mortality and neurodevelopmental disability were not reported. A single study reported no difference in days hospitalisation (MD 1.40, 95% CI -3.08 to 5.88; 116 infants; low certainty evidence), whereas data from two studies found an increase in days treatment (MD 2.71, 95% CI 0.22 to 5.21; 147 infants; low certainty) for infants treated with morphine. A single study reported no difference in breastfeeding, adverse events, or out of home placement. Morphine versus sublingual buprenorphine: there was no difference in treatment failure (RR 0.79, 95% CI 0.36 to 1.74; 3 studies, 113 infants; very low certainty evidence). Neonatal or infant mortality and neurodevelopmental disability were not reported. There was moderate certainty evidence of an increase in days hospitalisation (MD 11.45, 95% CI 5.89 to 17.01; 3 studies, 113 infants), and days treatment (MD 12.79, 95% CI 7.57 to 18.00; 3 studies, 112 infants) for infants treated with morphine. A single adverse event (seizure) was reported in infants exposed to buprenorphine. Morphine versus diluted tincture of opium (DTO): a single study (33 infants) reported no difference in days hospitalisation, days treatment or weight gain (low certainty evidence). Opioid versus clonidine: a single study (31 infants) reported no infant with treatment failure in either group. This study did not report seizures, neonatal or infant mortality and neurodevelopmental disability. There was low certainty evidence for no difference in days hospitalisation or days treatment. This study did not report adverse events. Opioid versus diazepam: there was a reduction in treatment failure from use of an opioid (RR 0.43, 95% CI 0.23 to 0.80; 2 studies, 86 infants; low certainty evidence). Seizures, neonatal or infant mortality and neurodevelopmental disability were not reported. A single study of 34 infants comparing methadone versus diazepam reported no difference in days hospitalisation or days treatment (very low certainty evidence). Adverse events were not reported. Opioid versus phenobarbital: there was a reduction in treatment failure from use of an opioid (RR 0.51, 95% CI 0.35 to 0.74; 6 studies, 458 infants; moderate certainty evidence). Subgroup analysis found a reduction in treatment failure in trials titrating morphine to ≧ 0.5 mg/kg/day (RR 0.21, 95% CI 0.10 to 0.45; 3 studies, 230 infants), whereas a single study using morphine < 0.5 mg/kg/day reported no difference compared to use of phenobarbital (subgroup difference P = 0.05). Neonatal or infant mortality and neurodevelopmental disability were not reported. A single study (111 infants) of paregoric versus phenobarbital reported seven infants with seizures in the phenobarbital group, whereas no seizures were reported in two studies (170 infants) comparing morphine to phenobarbital. There was no difference in days hospitalisation or days treatment. A single study (96 infants) reported no adverse events in either group. Opioid versus chlorpromazine: there was a reduction in treatment failure from use of morphine versus chlorpromazine (RR 0.08, 95% CI 0.01 to 0.62; 1 study, 90 infants; moderate certainty evidence). No seizures were reported in either group. There was low certainty evidence for no difference in days treatment. This trial reported no adverse events in either group. None of the included studies reported time to control of NAS. Data for duration and severity of NAS were limited, and we were unable to use these data in quantitative synthesis.

AUTHORS' CONCLUSIONS

Compared to supportive care alone, the addition of an opioid may increase duration of hospitalisation and treatment, but may reduce days to regain birthweight and the duration of supportive care each day. Use of an opioid may reduce treatment failure compared to phenobarbital, diazepam or chlorpromazine. Use of an opioid may have little or no effect on duration of hospitalisation or treatment compared to use of phenobarbital, diazepam or chlorpromazine. The type of opioid used may have little or no effect on the treatment failure rate. Use of buprenorphine probably reduces duration of hospitalisation and treatment compared to morphine, but there are no data for time to control NAS with buprenorphine, and insufficient evidence to determine safety. There is insufficient evidence to determine the effectiveness and safety of clonidine.

Pharmacometric dose optimization of buprenorphine in neonatal opioid withdrawal syndrome

Results from Blinded Buprenorphine OR Neonatal morphine solution (BBORN), a previous phase III trial in infants with neonatal opioid withdrawal syndrome (NOWS), demonstrated that sublingual buprenorphine resulted in a shorter duration of treatment and shorter length of hospital stay than the comparator, oral morphine. Objectives of Buprenorphine Pharmacometric Open Label Research study of Drug Exposure (BPHORE), a new trial with buprenorphine in a similar population, were to (1) optimize initial dose, up-titration to achieve symptom control and weaning steps of pharmacologic treatment and (2) investigate safety of the revised regimen. A pharmacodynamic model linked buprenorphine exposure to NOWS symptom scores. Adaptive dose regimens were simulated using BBORN results to compare dosing regimens for times to stabilization, weaning, and cessation. A clinical trial using model informed doses (BPHORE), was conducted. Simulations indicated benefits in time to stabilization and weaning when up-titration rates increased to 30%. Stabilization time was not greatly impacted by the starting dose. Time to wean and time to cessation were dose dependent. A weaning rate of 25% shortened time to cessation. Ten infants were enrolled in BPHORE using buprenorphine starting dose of 24 µg/kg/day, 33% titration, and 15% wean rate. Five subjects required adjuvant therapy. Half-maximal effective concentration (EC₅₀ ) values indicated maximum buprenorphine doses did not generate maximal effect size, suggesting potential efficacy of a further increased dose if a goal was to reduce the use of adjunct agents. Simulations indicated that further benefits can be gained by increasing starting doses of buprenorphine and increasing wean rates. Use of a model-based analysis to provide focused guidelines for care can be used with goals of reducing treatment time and hospital stays in infants with NOWS.

Using buprenorphine to treat neonatal abstinence syndrome: a quality improvement study

OBJECTIVE

To assess if treating neonatal abstinence syndrome (NAS) with sublingual buprenorphine (SLB) would decrease the mean duration of therapy (DOT) and length of birth hospital stay (LOS).

STUDY DESIGN

Conducted at a tertiary hospital with >6000 annual deliveries and a 2% incidence of NAS, a quality improvement study using plan-do-study-act (PDSA) cycles were utilized. Outcomes were measured using statistical process control (SPC) charts.

RESULTS

All NAS patients were treated with SLB, no adverse reactions were reported and the need for an adjunctive agent was static. SPC charts demonstrated decreased variability and special cause variation indicating a reduction in both DOT (from 14.5 to 8.5 days) and LOS (from 18.5 to 13 days).

Stability-indicating LC-MS Method for Determination of Stability of Extemporaneously Compounded Buprenorphine Oral Syringes for Neonatal Abstinence Syndrome

OBJECTIVE

In the hospital settings, buprenorphine is used for the treatment of patients with neonatal abstinence syndrome. It is extemporaneously compounded and stored in oral plastic syringes. However, limited information exists about the stability of buprenorphine and its compounded formulations when stored under specific conditions. Hence, we developed a stability-indicating high-performance liquid chromatography-mass spectrometry (LC-MS) method to analyze the stability of buprenorphine over time.

METHODS

A stability-indicating LC-MS method was developed to map the potential degradation peaks of buprenorphine when exposed to acidic, basic, and oxidative conditions. This method was used to study the stability of compounded buprenorphine oral syringes stored under refrigeration (2°C-8°C) and room temperature (25°C ± 2°C with 60% relative humidity). Syringes from each storage condition were assessed for stability using pH meter and stability-indicating LC-MS assay for 30 days.

RESULTS

Buprenorphine gets completely degraded in the presence of acid at the end of 1 hour of exposure. Various degradation peaks were identified using LC-MS assay for buprenorphine under acidic, basic, and peroxide conditions. Stability study of oral buprenorphine syringes showed no precipitation, cloudiness, or color change during this study at all storage conditions. The LC-MS assay revealed that buprenorphine oral syringes retained greater than 90% of the initial concentrations for 30 days.

CONCLUSIONS

Highly sensitive stability-indicating LC-MS method was developed for studying the stability of extemporaneously compounded buprenorphine oral syringes. This study demonstrates that buprenorphine extemporaneous formulation prepared according to the manufacturers' recommendations is stable under refrigerated or room temperature conditions for 30 days in oral plastic syringes.

Clinical pharmacology and dosing regimen optimization of neonatal opioid withdrawal syndrome treatments

In this paper, we review the management of neonatal opioid withdrawal syndrome (NOWS) and clinical pharmacology of primary treatment agents in NOWS, including morphine, methadone, buprenorphine, clonidine, and phenobarbital. Pharmacologic treatment strategies in NOWS have been mostly empirical, and heterogeneity in dosing regimens adds to the difficulty of extrapolating study results to broader patient populations. As population pharmacokinetics (PKs) of pharmacologic agents in NOWS become more well‐defined and knowledge of patient‐specific factors affecting treatment outcomes continue to accumulate, PK/pharmacodynamic modeling and simulation will be powerful tools to aid the design of optimal dosing regimens at the patient level. Although there is an increasing number of clinical trials on the comparative efficacy of treatment agents in NOWS, here, we also draw attention to the importance of optimizing the dosing regimen, which can be arguably equally important at identifying the optimal treatment agent.

Eat, Sleep, Console and Adjunctive Buprenorphine Improved Outcomes in Neonatal Opioid Withdrawal Syndrome

BACKGROUND

The worsening opioid crisis has increased the number of infants exposed to maternal opioids. Standard treatment of newborns exposed to opioids prenatally often requires prolonged hospitalization and separation of the mother-infant dyad. These practices can potentially increase severity of withdrawal symptoms, interrupt breastfeeding, and disturb mother-infant bonding. Use of the Eat, Sleep, Console (ESC) model may ameliorate symptoms, decrease mother-infant separation, and decrease hospital length of stay.

PURPOSE

To manage opioid exposed infants in a more holistic manner to decrease neonatal intensive care unit (NICU) admissions, reduce the need for pharmacotherapy, and evaluate response and total length of treatment after a unit protocol change from morphine to buprenorphine.

METHODS

Implemented ESC model, optimized nonpharmacologic bundle, and prescribed buprenorphine therapy instead of morphine as needed for adjunctive therapy.

RESULTS

Admissions of opioid-exposed infants from the Mother-Baby Unit (MBU) to the NICU decreased by 22%, and the number of infants who required pharmacotherapy was reduced by 50%. The average length of pharmacotherapy fell from 14 to 6.5 days.

IMPLICATIONS FOR PRACTICE

The successful implementation of the ESC model helped keep the mother-infant dyad together, reduced admissions to the NICU, and lessened the need for pharmacotherapy. The change to buprenorphine further reduced our average length of treatment.

IMPLICATIONS FOR RESEARCH

Investigation of monotherapy with buprenorphine needs to be evaluated as a valid treatment option. The buprenorphine dosing and weaning chart will need to be revised and modified if indicated.

Pharmacotherapy of neonatal opioid withdrawal syndrome: a review of pharmacokinetics and pharmacodynamics

INTRODUCTION

Neonatal opioid withdrawal syndrome (NOWS) often arises in infants born to mothers who used opioids during pregnancy. Morphine, methadone, and buprenorphine are the most common first-line treatments, whereas clonidine and phenobarbital are generally reserved for adjunctive therapy. These drugs exhibit substantial pharmacokinetic (PK) and pharmacodynamic (PD) variability. Current pharmacological treatments for NOWS are based on institutional protocols and largely rely on empirical treatment of patient symptoms.

AREAS COVERED

This article reviews the PK/PD of NOWS pharmacotherapies with a focus on the implication of physiological development and maturation. Body size-standardized clearance is consistently low in neonates, except for methadone. This can be ascribed to underdeveloped metabolic and elimination pathways. The effects of pharmacogenetics have been clarified especially for morphine. The PK/PD relationship of medications used in the treatment of NOWS is generally understudied.

EXPERT OPINION

Providing an appropriate opioid dose in neonates is challenging. Advancements in quantitative pharmacology and PK/PD modeling approaches facilitate identification of key factors driving PK/PD variability and characterization of exposure-response relationships. PK/PD model-informed simulations have been widely employed to define age-appropriate pediatric dosing regimens. The model-informed approach holds promise to aid more rational use of medications in the treatment of NOWS.

Outcome reporting in neonates experiencing withdrawal following opioid exposure in pregnancy: a systematic review

Background

Neonatal withdrawal secondary to in utero opioid exposure is a growing global concern stressing the psychosocial well-being of affected families and scarce hospital resources. In the ongoing search for the most effective treatment, randomized controlled trials are indispensable. Consistent outcome selection and measurement across randomized controlled trials enables synthesis of results, fostering the translation of research into practice. Currently, there is no core outcome set to standardize outcome selection, definition and reporting. This study identifies the outcomes currently reported in the literature for neonates experiencing withdrawal following opioid exposure during pregnancy.

Methods

A comprehensive literature search of MEDLINE, EMBASE and Cochrane Central was conducted to identify all primary research studies (randomized controlled trials, clinical trials, case-controlled studies, uncontrolled trials, observational cohort studies, clinical practice guidelines and case reports) reporting outcomes for interventions used to manage neonatal abstinence syndrome between July 2007 and July 2017. All “primary” and “secondary” neonatal outcomes were extracted by two independent reviewers and were assigned to one of OMERACT’s core areas of “pathophysiological manifestation”, “life impact”, “resource use”, “adverse events”, or “death”.

Results

Forty-seven primary research articles reporting 107 “primary” and 127 “secondary” outcomes were included. The most frequently reported outcomes were “duration of pharmacotherapy” (68% of studies, N = 32), “duration of hospital stay” (66% of studies, N = 31) and “withdrawal symptoms” (51% of studies, N = 24). The discrepancy between the number of times an outcome was reported and the number of articles was secondary to the use of composite outcomes. Frequently reported outcomes had heterogeneous definitions or were not defined by the study and were measured at different times. Outcomes reported in the literature to date were mainly assigned to the core areas “pathophysiologic manifestations” or “resource use”. No articles reported included parent or former patient involvement in outcome selections.

Conclusions

Inconsistent selection and definition of primary and secondary outcomes exists in the present literature of pharmacologic and nonpharmacologic interventions for managing opioid withdrawal in neonates. No studies involved parents in the process of outcome selection. These findings hinder evidence synthesis to generate clinically meaningful practice guidelines. The development of a specific core outcome set is imperative.

Emerging therapies for the treatment of neonatal abstinence syndrome

Objective: To examine the evidence for emerging treatment options, buprenorphine or clonidine, as monotherapy for the treatment of neonatal abstinence syndrome (NAS) against standards of care, morphine or methadone.Data sources: A PubMed literature search from 1946 to 2019 was performed using the terms NAS, neonatal withdrawal, buprenorphine and NAS, clonidine and NAS, morphine and NAS, methadone and NAS, opioids and pregnancy, opioids and NAS, prenatal exposure and opioids.Study selection and data extraction: Study evaluation was limited to English-language studies conducted in humans. Articles were eliminated if subjects did not have a formal diagnosis of NAS. Additionally, studies were eliminated if neonates received diluted tincture of opium. Additional references were identified from a manual citation review.Relevance to patient care and clinical practice: Eight articles were evaluated. Five articles compared buprenorphine to either morphine or methadone. Buprenorphine was found to decrease length of NAS treatment an average of 9.2 days and decrease hospital length of stay (LOS) an average of 8.2 days. Three articles evaluated the use of clonidine for NAS, two as an adjunct to morphine and one as monotherapy. Adjunctive clonidine plus morphine versus phenobarbital plus morphine both significantly reduced the total morphine treatment duration; however, patients remained on adjunctive phenobarbital significantly longer than clonidine. As monotherapy, clonidine was found to decrease NAS treatment an average of 11 days and decrease overall LOS an average of six days compared to morphine treatment.Conclusion: Treatment with buprenorphine or clonidine has shown favorable effects by reducing length of NAS treatment and LOS. These emerging therapies may be as effective as morphine or methadone for NAS, in combination with nonpharmacologic strategies. Long-term follow-up is needed.

Buprenorphine pharmacotherapy for the management of neonatal abstinence syndrome in methadone‐exposed neonates

We aimed to compare the outcomes of pharmacotherapy with either buprenorphine or methadone in infants treated for neonatal abstinence syndrome (NAS) secondary to intrauterine exposure to methadone. This is a multi‐center, retrospective cohort study to assess length of treatment (LOT), hospital length of stay (LOS), and cumulative opioid exposure between infants treated with either methadone or buprenorphine for NAS secondary to in utero exposure to methadone. Infants delivered at a gestational age ≥35 weeks and a maternal history of opioid‐use disorder and/or urine drug screen positive for methadone, and postnatal pharmacotherapy for NAS with either buprenorphine or methadone as first‐line opioid replacement therapy, were eligible. Median LOT, LOS, and cumulative opioid exposure were compared between buprenorphine‐ and methadone‐treated infants. A total of 156 infants (48 treated with buprenorphine and 108 with methadone) were identified. The median LOT and LOS for buprenorphine‐treated infants was 8 and 13 days compared with 15 and 20 days for methadone‐treated infants, respectively, P < .001 for both outcomes. Median cumulative opioid dose in morphine equivalents was 0.6 mg/kg for buprenorphine‐treated infants vs 1.05 mg/kg for methadone‐treated infants, P < .001. No adverse effects were noted among either group. Of infants treated with buprenorphine, 34 (71%) required the addition of adjunctive pharmacotherapy during the NICU stay, compared with 31 (32%) in the methadone‐treated group, P = .0008. However, significantly fewer infants treated with buprenorphine required continuation of therapy beyond discharge as compared with those treated with methadone. The difference is most likely a reflection of the protocols used by the sites. In infants that required pharmacotherapy for NAS secondary to intrauterine exposure to methadone, treatment with buprenorphine, compared with methadone therapy, was associated with better outcomes. If confirmed with prospective data, buprenorphine could be considered first‐line therapy for the two medication‐assisted treatment regimens recommended by the American College of Obstetricians and Gynecologists.

Comparative effectiveness of opioid replacement agents for neonatal opioid withdrawal syndrome: a systematic review and meta-analysis

OBJECTIVE(S)

To compare short-term treatment outcomes of opioid pharmacotherapy for neonatal opioid withdrawal syndrome (NOWS).

STUDY DESIGN

PubMed/MEDLINE, Embase, PsycINFO, and The Cochrane Library were searched from inception through September 30, 2018. Primary outcome was treatment duration (LOT). Secondary outcomes included hospitalization duration (LOS) and rate of adjunct drug needed (RAD).

RESULTS

Of 753 publications, 11 studies met inclusion criteria. There was no difference in LOT (WMD -1.39 [-5.79 to -3.01] days, I² 82%) or LOS (WMD -1.48 [-5.75 to -2.79] days, I² 92%) between morphine and methadone. RAD with morphine was higher (RR 1.51 [1.35-1.69], I² 0%). Buprenorphine was associated with shorter LOT (WMD 7.70 [0.88-14.53] days, I² 76%) and LOS (WMD 5.61 [-0.01 to -11.24] days, I² 60%) compared with morphine, in addition to methadone according to two cohort studies.

CONCLUSIONS

Methadone had superior primary treatment success compared with morphine. Buprenorphine was associated with the shortest overall durations of treatment and hospitalization.

Opioids in Breast Milk: Pharmacokinetic Principles and Clinical Implications

Safety of maternal drug therapy during breastfeeding may be assessed from estimated levels of drug exposure of the infant through milk. Pharmacokinetic (PK) principles predict that the lower the clearance is, the higher the infant dose via milk will be. Drugs with low clearance (<1 mL/[kg·min]) are likely to cause an infant exposure level greater than 10% of the weight-adjusted maternal dose even if the milk-to-plasma concentration ratio is 1. Most drugs cause relatively low-level exposure below 10% of the weight-adjusted maternal dose, but opioids require caution because of their potential for severe adverse effects. Furthermore, substantial individual variations of drug clearance exist in both mother and infant, potentially causing drug accumulation over time in some infants even if an estimated dose of the drug through milk is small. Such PK differences among individuals are known not only for codeine and tramadol through pharmacogenetic variants of CYP2D6 but also for non-CYP2D6 substrate opioids including oxycodone, indicating difficulties of eliminating PK uncertainty by simply replacing an opioid with another. Overall, opioid use for pain management during labor and delivery and subsequent short-term use for 2-3 days are compatible with breastfeeding. In contrast, newly initiated and prolonged maternal opioid therapy must follow a close monitoring program of the opioid-naive infants. Until more safety data become available, treatment duration of newly initiated opioids in the postpartum period should be limited to 2-3 days in unsupervised outpatient settings. Opioid addiction treatment with methadone and buprenorphine during pregnancy may continue into breastfeeding, but infant conditions must be monitored.

Therapeutic approaches for neonatal abstinence syndrome: a systematic review of randomized clinical trials

Neonatal abstinence syndrome (NAS) which is observed in 55-94% of the newborns from opioids-taking mothers produces deleterious neurological symptoms. Various pharmacological therapies have been investigated in neonates with NAS. This article reviews all studies on NAS treatment to analyze the duration of treatment, length of hospitalization and possible drug adverse effects. The search was limited to the randomized clinical trials which examined the treatments of neonates with NAS. Scientific databases including PubMed, Cochrane Library, ISI Web of Science, Embase and Scopus were systematically searched. Retrieved articles were reviewed by two researchers and evaluated using the JADAD scoring system. Finally, the treatment duration, hospitalization length and drug side-effects were extracted. Methadone, buprenorphine and clonidine were found more effective than morphine. Diluted tincture of opium (DTO) in combination with phenobarbital or clonidine was significantly more effective than DTO alone. Clonidine was a significantly better adjunctive therapy than phenobarbital in reducing morphine treatment days. No significant difference was observed between morphine and DTO effectiveness. Deciding the optimal regimen to manage symptomatic NAS, as a single or an adjunct therapy is not possible based on the literature, due to the low quality, small size and short-term treatment considered in the published studies. Graphical abstract Process of selecting trials included in the present systematic review.

Neonatal abstinence syndrome

Neonates exposed prenatally to opioids will often develop a collection of withdrawal signs known as neonatal abstinence syndrome (NAS). The incidence of NAS has substantially increased in recent years placing an increasing burden on the healthcare system. Traditional approaches to assessment and management have relied on symptom-based scoring tools and utilization of slowly decreasing doses of medication, though newer models of care focused on non-pharmacologic interventions and rooming-in have demonstrated promise in reducing length of hospital stay and medication usage. Data on long-term outcomes for both traditional and newer approaches to care of infants with NAS is limited and an important area of future research. This review will examine the history, incidence and pathophysiology of NAS. We will also review diagnostic screening approaches, scoring tools, differing management approaches and conclude with recommendations for continued work to improve the care of infants with NAS.

Pharmacological and non-pharmacological treatments for the Neonatal Abstinence Syndrome (NAS)

Neonatal abstinence syndrome is defined by signs and symptoms of withdrawal that infants develop after intrauterine maternal drug exposure. All infants with documented in utero opioid exposure, or a high pre-test probability of exposure should have monitoring with a standard assessment instrument such as a Finnegan Score. A Finnegan score of >8 is suggestive of opioid exposure, even in the absence of declared use during pregnancy. At least half of infants in most locales can be treated without the use of pharmacologic means. For this reason, symptom scores will drive the decision for pharmacologic therapy. Nevertheless, all infants, regardless of initial manifestations, should be first be managed with non-pharmacologic approaches which in turn, should not be considered as the sole alternative to drug therapy, but rather, as the base upon which all patients are treated. Those who continue to have symptoms despite supportive care should be pharmacologically treated, which in the most severe cases, is life-saving.

Pharmacological Treatments for Neonatal Abstinence Syndrome: A Systematic Review and Network Meta-analysis

IMPORTANCE

Incidence of neonatal abstinence syndrome is rising rapidly, and optimal pharmacotherapy may meaningfully reduce length of treatment.

OBJECTIVE

To compare pharmacological therapies for neonatal abstinence syndrome.

DATA SOURCES

Systematic review and network meta-analysis of Medline (1946-June 2018), Embase (1974-June 2018), Cochrane CENTRAL (1966-June 2018), Web of Science (1900-June 2018), and ClinicalTrials.gov (June 2018).

STUDY SELECTION

Randomized clinical trials of pharmacological treatments for neonatal abstinence syndrome alone or in combination with adjuvant treatments. Abstract, title, and full-text screening were conducted independently by 2 reviewers (T.D. and C.G.).

DATA EXTRACTION AND SYNTHESIS

Data extraction was conducted independently by 2 reviewers (T.D. and C.G.) according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA)-Network Meta-Analyses guidelines. Quality was assessed with the Cochrane Risk of Bias tool and data were pooled with fixed-effect models as a result of the low number of trials that were included in the analysis.

MAIN OUTCOMES AND MEASURES

The primary outcome was the length of treatment. The length of stay, need for adjuvant therapy, and adverse events were considered as secondary outcomes.

RESULTS

Eighteen trials (N = 1072) were eligible for inclusion. The treatments that were included in the length of treatment analysis were buprenorphine, clonidine, diluted tincture of opium and clonidine, diluted tincture of opium, morphine, methadone, and phenobarbital. Sublingual buprenorphine was considered the optimal treatment for a reduction in the length of treatment (days: mean difference vs morphine, -12.75 [95% CI, -17.97 to -7.58]; median rank, 1 [3-1]) and length of stay (days: mean difference vs morphine, -11.43 [95% CI, -16.95 to -5.82]; median rank, 1 [3-1]) but not the need for adjuvant treatment (odds ratio vs morphine, 1.23 [95% CI, 0.46-3.44]; median rank, 3 [5-1]). The results were robust to bias but sensitive to imprecision.

CONCLUSIONS AND RELEVANCE

The current evidence suggests that buprenorphine is the optimal treatment for neonatal abstinence treatment, but limitations are considerable and wide-scale adoption requires a large multisite trial. Morphine, which is considered standard of care in most hospitals, was the lowest-ranked opioid for length of treatment and length of stay.

Buprenorphine for the Treatment of Neonatal Abstinence Syndrome

Objective: To summarize the available data for using buprenorphine in neonatal abstinence syndrome and discuss these data in context of the current standard of care therapies, oral morphine and oral methadone. Data Sources: A literature search was conducted using PubMed (1949-May 2018) and EMBASE (1980-May 2018). Combinations of the search terms “buprenorphine,” “neonatal,” and “neonatal abstinence syndrome” were used. Study Selection and Data Extraction: All full-length, English-language studies were included in this review. Data Synthesis: A total of 4 studies were included in this review including 1 retrospective cohort study, 2 prospective single-center open-label randomized trials, and 1 prospective single-center, double-blind study. Oral morphine was the comparator in 3 studies, and oral methadone was the comparator in one. Buprenorphine was associated with a significant reduction in duration of treatment in 3 of the 4 studies and was associated with a significant reduction in duration of hospital stay in 3 of the 4 studies. In the randomized, double-blinded trial, buprenorphine had a significantly reduced duration of treatment (15 vs 28 days, P < .001) and duration of hospital stay (21 vs 33 days, P < .001). The requirement of adjunct treatment was similar between groups in all 4 studies, and buprenorphine did not have any significant adverse reactions in comparison with morphine and methadone. Conclusions: Buprenorphine appears to be a safe option for treating neonatal abstinence syndrome that is potentially superior to the current standard of care therapies with respect to duration of treatment and hospital length of stay.

Finding the right treatment for neonatal abstinence syndrome: is this the right time?

Neonatal abstinence syndrome (NAS) is a constellation of withdrawal symptoms in infants born to mothers with chronic opioid use during pregnancy. A proportion of infants will need pharmacotherapy in addition to non-pharmacological interventions. In this article, we reviewed a clinical trial comparing the use of sublingual buprenorphine to oral morphine (the most widely used pharmacotherapy for NAS) in term infants. The primary end point was the duration of treatment, and secondary end points were the length of hospital stay, the proportion of infants who needed supplemental phenobarbital, and safety.

Update of the Scientific Opinion on opium alkaloids in poppy seeds

Poppy seeds are obtained from the opium poppy (Papaver somniferum L.). They are used as food and to produce edible oil. The opium poppy plant contains narcotic alkaloids such as morphine and codeine. Poppy seeds do not contain the opium alkaloids, but can become contaminated with alkaloids as a result of pest damage and during harvesting. The European Commission asked EFSA to provide an update of the Scientific Opinion on opium alkaloids in poppy seeds. The assessment is based on data on morphine, codeine, thebaine, oripavine, noscapine and papaverine in poppy seed samples. The CONTAM Panel confirms the acute reference dose (ARfD) of 10 μg morphine/kg body weight (bw) and concluded that the concentration of codeine in the poppy seed samples should be taken into account by converting codeine to morphine equivalents, using a factor of 0.2. The ARfD is therefore a group ARfD for morphine and codeine, expressed in morphine equivalents. Mean and high levels of dietary exposure to morphine equivalents from poppy seeds considered to have high levels of opium alkaloids (i.e. poppy seeds from varieties primarily grown for pharmaceutical use) exceed the ARfD in most age groups. For poppy seeds considered to have relatively low concentrations of opium alkaloids (i.e. primarily varieties for food use), some exceedance of the ARfD is also seen at high levels of dietary exposure in most surveys. For noscapine and papaverine, the available data do not allow making a hazard characterisation. However, comparison of the dietary exposure to the recommended therapeutical doses does not suggest a health concern for these alkaloids. For thebaine and oripavine, no risk characterisation was done due to insufficient data. However, for thebaine, limited evidence indicates a higher acute lethality than for morphine and the estimated exposure could present a health risk.

The Pharmacokinetics and Pharmacodynamics of Buprenorphine in Neonatal Abstinence Syndrome

Neonatal abstinence syndrome (NAS) is a condition affecting newborns that are exposed to an opioid in utero. In a randomized, controlled trial assessing the efficacy of buprenorphine and morphine in NAS, blood samples were analyzed from a subset of patients receiving buprenorphine along with NAS scores. The data were used to validate and adapt an existing model of buprenorphine in neonates and to identify relationships between buprenorphine or norbuprenorphine pharmacokinetics (PK) and efficacy or safety. The time to NAS stabilization was found to decrease with increasing buprenorphine exposure. This pharmacokinetic-pharmacodynamic (PK-PD) relationship was able to be quantified and adequately described with a mathematical model. The findings confirm a previous PK model of buprenorphine and extend the model to describe the PK of norbuprenorphine and to identify a novel PK-PD relationship of buprenorphine in NAS. This model will allow optimization of dosing strategies in future clinical trials.

Treating Women Who Are Pregnant and Parenting for Opioid Use Disorder and the Concurrent Care of Their Infants and Children: Literature Review to Support National Guidance

OBJECTIVES

The prevalence of opioid use disorder (OUD) during pregnancy is increasing. Practical recommendations will help providers treat pregnant women with OUD and reduce potentially negative health consequences for mother, fetus, and child. This article summarizes the literature review conducted using the RAND/University of California, Los Angeles Appropriateness Method project completed by the US Department of Health and Human Services Substance Abuse and Mental Health Services Administration to obtain current evidence on treatment approaches for pregnant and parenting women with OUD and their infants and children.

METHODS

Three separate search methods were employed to identify peer-reviewed journal articles providing evidence on treatment methods for women with OUD who are pregnant or parenting, and for their children. Identified articles were reviewed for inclusion per study guidelines and relevant information was abstracted and summarized.

RESULTS

Of the 1697 articles identified, 75 were included in the literature review. The perinatal use of medication for addiction treatment (MAT, also known as medication-assisted treatment), either methadone or buprenorphine, within comprehensive treatment is the most accepted clinical practice, as withdrawal or detoxification risks relapse and treatment dropout. Medication increases may be needed with advancing pregnancy, and are not associated with more severe neonatal abstinence syndrome (NAS). Switching medication prenatally is usually not recommended as it can destabilize opioid abstinence. Postnatally, breastfeeding is seen as beneficial for the infant for women who are maintained on a stable dose of opioid agonist medication. Less is known about ideal pain management and postpartum dosing regimens. NAS appears generally less severe following prenatal exposure to buprenorphine versus methadone. Frontline NAS medication treatments include protocol-driven methadone and morphine dosing in the context of nonpharmacological supports.

CONCLUSIONS

Women with OUD can be treated with methadone or buprenorphine during pregnancy. NAS is an expected and manageable condition. Although research has substantially advanced, opportunities to guide future research to improve maternal and infant outcomes are provided.

Buprenorphine in Neonatal Abstinence Syndrome

Infants exposed in utero to opioids will demonstrate a withdrawal syndrome known as neonatal abstinence syndrome (NAS). Buprenorphine is a long-acting opioid with therapeutic use in medication-assisted treatment of opioid dependency in adults and adolescents. Emerging data from clinical trials and treatment cohorts demonstrate the efficacy and safety of sublingual buprenorphine for those infants with NAS who require pharmacologic treatment. Pharmacometric modeling will assist in defining the exposure-response relationships and facilitate dose optimization.

Pharmacotherapy for Neonatal Abstinence Syndrome: Choosing the Right Opioid or No Opioid at All

Neonatal abstinence syndrome (NAS) from in utero opioid exposure has reached epidemic levels in the United States. Although nonpharmacologic therapies form the foundation of care, many neonates require pharmacotherapy. Morphine represents the most widely used first-line agent and effectively treats the symptoms of withdrawal. However, methadone or buprenorphine may facilitate earlier discharge. Although phenobarbital is traditionally used when opioids fail, clonidine may be a more appropriate adjunctive agent to minimize negative neurodevelopmental impact. Consideration of the available data allows hospitals to generate effective pharmacologic strategies to manage NAS while further research continues.

Neonatal abstinence syndrome: where are we, and where do we go from here?

PURPOSE OF REVIEW

Over the last 15 years the prevalence of neonatal abstinence syndrome (NAS) increased almost five-fold. A considerable diversity seems to prevail in the management of NAS. This review provides an overview of factors affecting the expression and course of NAS, and recent developments in NAS assessment and treatment.

RECENT FINDINGS

Apart from different pharmacological and nonpharmacological treatment modalities, maturity of the infant and genetic variations likely are (co)responsible for interpatient variability in NAS severity, despite similar maternal exposure. Recent efforts concerning the further development of NAS severity scoring systems focus on the development of brief screening measures; in addition, pupil diameter and skin conductance have been proposed as complements to observer-rated scales. The decrease in incidence of NAS begins in the appropriate management of medication assisted treatment of the mother.

SUMMARY

Mitigating the negative outcomes for infants affected by NAS, their mothers and the healthcare system implies, first and foremost, developing and implementing an organized protocol for the management of NAS, and the homogenous use of a standardized scoring system utilizing interobserver reliability and a guide for medication initiation, maintenance, and weaning which is consistent with traditional methods of treatment for neonates.

Buprenorphine for the Treatment of the Neonatal Abstinence Syndrome

BACKGROUND

Current pharmacologic treatment of the neonatal abstinence syndrome with morphine is associated with a lengthy duration of therapy and hospitalization. Buprenorphine may be more effective than morphine for this indication.

METHODS

In this single-site, double-blind, double-dummy clinical trial, we randomly assigned 63 term infants (≥37 weeks of gestation) who had been exposed to opioids in utero and who had signs of the neonatal abstinence syndrome to receive either sublingual buprenorphine or oral morphine. Infants with symptoms that were not controlled with the maximum dose of opioid were treated with adjunctive phenobarbital. The primary end point was the duration of treatment for symptoms of neonatal opioid withdrawal. Secondary clinical end points were the length of hospital stay, the percentage of infants who required supplemental treatment with phenobarbital, and safety.

RESULTS

The median duration of treatment was significantly shorter with buprenorphine than with morphine (15 days vs. 28 days), as was the median length of hospital stay (21 days vs. 33 days) (P<0.001 for both comparisons). Adjunctive phenobarbital was administered in 5 of 33 infants (15%) in the buprenorphine group and in 7 of 30 infants (23%) in the morphine group (P=0.36). Rates of adverse events were similar in the two groups.

CONCLUSIONS

Among infants with the neonatal abstinence syndrome, treatment with sublingual buprenorphine resulted in a shorter duration of treatment and shorter length of hospital stay than treatment with oral morphine, with similar rates of adverse events. (Funded by the National Institute on Drug Abuse; BBORN ClinicalTrials.gov number, NCT01452789 .).

Neonatal Abstinence Syndrome: Presentation and Treatment Considerations

The increase in opioid use among the general population is reflected in pregnant women and neonatal abstinence syndrome (NAS) statistics. This increase has produced an unprecedented focus on NAS from both the political-judicial sphere and the medical community. Under the banner of fetal protection, judges and prosecutors have implemented punitive approaches against women who use prescribed and nonprescribed opioids during pregnancy, including arrest, civil commitment, detention, prosecution, and loss of custody or termination of parental rights. Within the medical community, questions have been raised regarding protocols to detect prenatal drug exposure at delivery, NAS treatment protocols, the need for quality-improvement strategies to standardize care and reduce length of stay for mother and infant, and the benefits of engaging the mother in the care of her infant. It is not uncommon for the expression of strong discordant views on these issues both between and among these political-judicial and medical constituencies. Closely examining the issues often reveal a lack of understanding of substance use disorders, their treatment, and the occurrence and treatment of NAS. This study provides an in-depth examination of NAS, including variations in presentation and factors that impact the efficacy of treatment, and also identifying questions that remain unanswered. Finally, 4 key areas on which future research should focus to guide both medical care and public policy are discussed.

A Novel Strategy for Attenuating Opioid Withdrawal in Neonates

The rate of Neonatal Abstinence Syndrome (NAS) has drastically increased over the past decade. The average hospital expense per NAS patient has tripled, while the number of babies born to opioid-dependent mothers has increased to 5 in 1000 births. Current treatment options are limited to opioid replacement and tapering. Consequently, we examined the efficacy of prenatal, low-dose and short-term vigabatrin (γ-vinyl GABA, GVG) exposure for attenuating these symptoms as well as the metabolic changes observed in the brains of these animals upon reaching adolescence. Pregnant Sprague-Dawley rats were treated in one of four ways: 1) saline; 2) morphine alone; 3) morphine+GVG at 25 mg/kg; 4) morphine+GVG at 50 mg/kg. Morphine was administered throughout gestation, while GVG administration occurred only during the last 5 days of gestation. On post-natal day 1, naloxone-induced withdrawal behaviours were recorded in order to obtain a gross behaviour score. Approximately 28 days following birth, ¹⁸FDG microPET scans were obtained on these same animals (Groups 1, 2, and 4). Morphine-treated neonates demonstrated significantly higher withdrawal scores than saline controls. However, GVG at 50 but not 25 mg/kg/day significantly attenuated them. Upon reaching adolescence, morphine treated animals showed regionally specific changes in ¹⁸FDG uptake. Again, prenatal GVG exposure blocked them. These data demonstrate that low-dose, short-term prenatal GVG administration blocks naloxone-induced withdrawal in neonates. Taken together, these preliminary findings suggest that GVG may provide an alternative and long-lasting pharmacologic approach for the management of neonatal and adolescent symptoms associated with NAS.

Maternal Buprenorphine Maintenance and Lactation

BACKGROUND

In addition to the well-known benefits of human milk and breastfeeding for the mother and infant, breastfeeding may mitigate neonatal abstinence syndrome severity in prenatally opioid-exposed infants. However, lack of conclusive data regarding the extent of the presence of buprenorphine and active metabolites in human milk makes the recommendation of breastfeeding for buprenorphine-maintained women difficult for many providers.

OBJECTIVE

This study seeks to determine the concentrations of buprenorphine and its active metabolites (norbuprenorphine, buprenorphine-glucuronide, and norbuprenorphine-glucuronide) in human milk, maternal plasma, and infant plasma of buprenorphine-maintained women and their infants.

METHODS

Up to 10 buprenorphine-maintained women provided paired breast milk and plasma samples at 2, 3, 4, 14, and 30 days postdelivery, and 9 infants provided plasma samples on day 14 of life. All samples were analyzed via liquid chromatography tandem mass spectrometry to determine concentrations of buprenorphine, norbuprenorphine, buprenorphine-glucuronide, and norbuprenorphine-glucuronide by a fully validated method.

RESULTS

Concentrations of buprenorphine and metabolites are low in human milk and maternal plasma. Breastfed infant plasma concentrations of buprenorphine were low or undetectable and metabolite concentrations undetectable at 14 days of infant age. There were significant correlations between maternal buprenorphine dose and maternal plasma and human milk buprenorphine concentrations.

CONCLUSION

These data find low concentrations of buprenorphine and metabolites in human milk and lend support to the recommendation for lactation among stable buprenorphine-maintained women. However, the correlation between maternal dose and maternal plasma and human milk buprenorphine concentrations bears further study.

Neonatal abstinence syndrome: Pharmacologic strategies for the mother and infant

Opioid use in pregnancy has increased dramatically over the past decade. Since prenatal opioid use is associated with numerous obstetrical and neonatal complications, this now has become a major public health problem. In particular, in utero opioid exposure can result in neonatal abstinence syndrome (NAS) which is a serious condition characterized by central nervous system hyperirritability and autonomic nervous system dysfunction. The present review seeks to define current practices regarding the approach to the pregnant mother and neonate with prenatal opiate exposure. Although the cornerstone of prenatal management of opioid dependence is opioid maintenance therapy, the ideal agent has yet to be definitively established. Pharmacologic management of NAS is also highly variable and may include an opioid, barbiturate, and/or α-agonist. Genetic factors appear to be associated with the incidence and severity of NAS. Establishing pharmacogenetic risk factors for the development of NAS has the potential for creating opportunities for "personalized genomic medicine" and novel, individualized therapeutic interventions.

Exploring the Use of Chronic Opioid Therapy for Chronic Pain: When, How, and for Whom?

This article provides a broad overview regarding intent to initiate and consider ongoing chronic opioid therapy (COT) for treatment of chronic noncancer pain (CNCP). COT should be an individualized decision based on a comprehensive evaluation, assessment, and monitoring. It is imperative that providers discuss various risks and benefits of COT initially and at follow-up visits, and continue appropriate monitoring and follow-up at regular intervals. The decision to initiate or continue opioid therapy is based on clinical judgment; however, it is understood that opioid and other medication therapy represent one piece of the complete treatment plan for patients with CNCP.

Opioids in pregnancy and neonatal abstinence syndrome

Opiate use in pregnancy has increased dramatically over the past decade and now represents a major public health problem. More women are using prescription opioids, illegal opioids, and opioid-substitution therapy. These drugs have been associated with numerous obstetrical complications including intrauterine growth restriction, placental abruption, preterm delivery, oligohydramnios, stillbirth, and maternal death. Neonatal complications are also significant, such as an increased risk of mortality as well as neonatal abstinence syndrome (NAS). NAS is a serious and highly variable condition characterized by central nervous system hyperirritability and autonomic nervous system dysfunction. The present review seeks to define current practices regarding the management of opiate dependence in pregnancy and care of the neonate with prenatal opiate exposure. Since genetic factors appear to be associated with the incidence and severity of NAS, opportunities for "personalized genomic medicine" and unique therapeutic interventions could be developed in the future.

Neonatal abstinence syndrome: Historical perspective, current focus, future directions

BACKGROUND

Neonatal abstinence syndrome (NAS) occurs following prenatal opioid exposure. It is characterized by signs and symptoms indicating central nervous system hyperirritability and autonomic nervous system, gastrointestinal tract, and respiratory system dysfunction.

OBJECTIVE

This article: (1) briefly reviews NAS history, including initial identification, assessment, and treatment efforts; (2) summarizes the current status of and current issues surrounding recent NAS assessment and treatment, and (3) details future directions in NAS conceptualization, measurement, and treatment.

RESULTS

Mortality rate estimates in neonates treated for NAS exceeded 33%, and surpassed 90% for un-treated infants during the late-1800s until the mid-1900s. The focus of both assessment and treatment over the past 50years is predominantly due to two forces. First, methadone pharmacotherapy for "heroin addiction" led to women in methadone maintenance programs who were, or became pregnant. The second was defining NAS and developing a measure of neonatal withdrawal, the Neonatal Abstinence Scoring System (NASS). Various NAS treatment protocols were based on the NASS as well as other NAS measures.

CONCLUSIONS

Future research must focus on psychometrically sound screening and assessment measures of neonatal opioid withdrawal for premature, term and older infants, measuring and treating possible withdrawal from non-opioids, particularly benzodiazepines, integrated non-pharmacological treatment of NAS, weight-based versus symptom-based treatment of NAS, and second-line treatment for NAS.

Population Pharmacokinetic Model of Sublingual Buprenorphine in Neonatal Abstinence Syndrome

OBJECTIVE

Neonatal abstinence syndrome (NAS)--a clinical entity of infants from in utero exposure to psychoactive xenobiotic and buprenorphine--has been successfully used to treat NAS. However, nothing is known about the pharmacokinetics (PK) of buprenorphine in neonates with NAS. To our knowledge, this is the first study to investigate the population pharmacokinetic of sublingual buprenorphine in neonates with NAS.

DESIGN

A retrospective population PK analysis of: (1) neonates with NAS treated with sublingual buprenorphine in randomized, double blinded clinical study and (2) data from healthy adults from a previously published pharmacokinetic study.

SETTING

Neonatal intensive care unit and general clinical research unit.

PATIENTS

Twenty-four neonates with NAS and five healthy adults.

INTERVENTIONS

All participants received sublingual buprenorphine per study protocol.

MEASUREMENTS AND MAIN RESULTS

A total of 303 PK data from 29 neonates and adults were used for model development. A population pharmacokinetic analysis was conducted using a first order conditional estimation with interaction in the NONMEM software program. A two-compartment linear PK model with first-order absorption process best described the pharmacokinetics of sublingual buprenorphine in neonates. The apparent clearance (CL) of buprenorphine was linearly related to body weight and matured with increasing age via two distinct saturated pathways. A typical neonate with NAS (body weight, 2.9 kg; postnatal age; 5.4 days) had a CL of 3.5 L/kg/hour and elimination half-life of 11 hours. Phenobarbital did not affect the clearance of buprenorphine compared to neonates of similar age and weight.

CONCLUSIONS

This is the first study to investigate the population PK of sublingual buprenorphine in neonatal NAS. To our knowledge, this is also the first report to describe the age-dependent changes of buprenorphine PK in this patient population. No buprenorphine dose adjustment is needed for neonates with NAS treated with buprenorphine and concurrent phenobarbital.

Phenobarbital versus morphine in the management of neonatal abstinence syndrome, a randomized control trial

BACKGROUNDS

Evaluating the efficacy of the loading and tapering dose of Phenobarbital versus oral Morphine in the management of NAS.

METHODS

This randomized, open-label, controlled trial was conducted on 60 neonates born to illicit drugs dependent mothers at Vali-Asr and Akbar-Abadi hospitals, Tehran, Iran, who exhibited NAS requiring medical therapy. The neonates were randomized to receive either: Oral Morphine Sulfate or a loading dose of Phenobarbital followed by a tapering dose. The duration of treatment required for NAS resolution, the total hospital stay and the requirement for additional second line treatment were compared between the treatment groups.

RESULTS

The Mean ± Standard Deviation for the duration of treatment required for the resolution of NAS was 8.5 ± 5 days in the Morphine group and 8.5 ± 4 days in the Phenobarbital group (P = 0.9). The duration of total hospital stay was 12.6 ± 5.6 days in the Morphine group and 12.5 ± 5.3 days in the Phenobarbital group (P = 0.7). 3.3 % in the Morphine group versus 6.6 % in the Phenobarbital group required adjunctive treatment (P = 0.5).

CONCLUSIONS

There were no significant differences in the duration of treatment, duration of hospital stay, and the requirement for adjunctive treatment, between the neonates with NAS who received Morphine Sulfate and neonates who received a loading and tapering dose of Phenobarbital.

TRIAL REGISTRATION

This study is registered at the Iranian Registry of Clinical Trials ( www.irct.ir ) which is a Primary Registry in the WHO Registry Network. (Registration Number =  IRCT201406239568N8 ).

Neonatal opioid withdrawal syndrome

Neonatal opioid withdrawal syndrome is common due to the current opioid addiction epidemic. Infants born to women covertly abusing prescription opioids may not be identified as at risk until withdrawal signs present. Buprenorphine is a newer treatment for maternal opioid addiction and appears to result in a milder withdrawal syndrome than methadone. Initial treatment is with nonpharmacological measures including decreasing stimuli, however pharmacological treatment is commonly required. Opioid monotherapy is preferred, with phenobarbital or clonidine uncommonly needed as adjunctive therapy. Rooming-in and breastfeeding may decease the severity of withdrawal. Limited evidence is available regarding long-term effects of perinatal opioid exposure.

Ondansetron pharmacokinetics in pregnant women and neonates: towards a new treatment for neonatal abstinence syndrome

Ondansetron is the drug of choice to prevent nausea in women undergoing cesarean surgery and can be used to prevent neonatal abstinence syndrome (NAS). The pharmacokinetics of ondansetron have not been characterized in pregnant women or in newborns. A nonlinear mixed-effects modeling approach was used to analyze plasma samples obtained from 20 nonpregnant and 40 pregnant women following a single administration of 4 or 8 mg ondansetron, from umbilical cord blood at delivery, and from neonates after birth. The analysis indicates that: ondansetron disposition is not affected by pregnancy (P > 0.05), but influenced by dose (P < 0.05), and is characterized by rapid transplacental transfer and longer elimination half-life in neonates compared to their mother. A dosing regimen for prevention of NAS was designed based on the model. The regimen involves IV administration of 4 mg to the mothers shortly before cord clamping, or oral administration of 0.07 mg/kg (or equivalently 0.04 mg/kg IV) to neonates.

Variation in treatment of neonatal abstinence syndrome in US children's hospitals, 2004-2011

OBJECTIVE

Neonatal abstinence syndrome (NAS) is a drug withdrawal syndrome experienced by opioid-exposed infants. There is no standard treatment for NAS and surveys suggest wide variation in pharmacotherapy for NAS. Our objective was to determine whether different pharmacotherapies for NAS are associated with differences in outcomes and to determine whether pharmacotherapy and outcome vary by hospital.

STUDY DESIGN

We used the Pediatric Health Information System Database from 2004 to 2011 to identify a cohort of infants with NAS requiring pharmacotherapy. Mixed effects hierarchical negative binomial models evaluated the association between pharmacotherapy and hospital with length of stay (LOS), length of treatment (LOT) and hospital charges, after adjusting for socioeconomic variables and comorbid clinical conditions.

RESULT

Our cohort included 1424 infants with NAS from 14 children's hospitals. Among hospitals in our sample, six used morphine, six used methadone and two used phenobarbital as primary initial treatment for NAS. In multivariate analysis, when compared with NAS patients initially treated with morphine, infants treated with methadone had shorter LOT (incidence rate ratio (IRR) = 0.55; P < 0.0001) and LOS (IRR = 0.60; P < 0.0001). Phenobarbital as a second-line agent was associated with increased LOT (IRR = 2.09; P<0.0001), LOS (IRR = 1.78; P < 0.0001) and higher hospital charges (IRR = 1.84; P < 0.0001). After controlling for case-mix, hospitals varied in LOT, LOS and hospital charges.

CONCLUSION

We found variation in hospital in treatment for NAS among major US children's hospitals. In analyses controlling for possible confounders, methadone as initial treatment was associated with reduced LOT and hospital stay.

Neonatal abstinence syndrome: essentials for the practitioner

The incidence of neonatal abstinence syndrome (NAS) has increased dramatically during the past 15 years, likely due to an increase in antepartum maternal opiate use. Optimal care of these patients is still controversial because of the available published literature lacking sufficient sample size, placebo control, and comparative pharmacologic trials. Primary treatment for NAS consists of opioid replacement therapy with either morphine or methadone. Paregoric and tincture of opium have been abandoned because of relative safety concerns. Buprenorphine is emerging as a treatment option with promising initial experience. Adjunctive agents should be considered for infants failing treatment with opioid monotherapy. Traditionally, phenobarbital has been used as adjunctive therapy; however, results of clonidine as adjunctive therapy for NAS appear to be beneficial. Future directions for research in NAS should include validating a simplified scoring tool, conducting comparative studies, exploring home management options, and optimizing management through pharmacogenomics.

Review of the assessment and management of neonatal abstinence syndrome

Neonatal abstinence syndrome (NAS) secondary to in-utero opioid exposure is an increasing problem. Variability in assessment and treatment of NAS has been attributed to the lack of high-quality evidence to guide management of exposed neonates. This systematic review examines available evidence for NAS assessment tools, nonpharmacologic interventions, and pharmacologic management of opioid-exposed infants. There is limited data on the inter-observer reliability of NAS assessment tools due to lack of a standardized approach. In addition, most scales were developed prior to the prevalent use of prescribed prenatal concomitant medications, which can complicate NAS assessment. Nonpharmacologic interventions, particularly breastfeeding, may decrease NAS severity. Opioid medications such as morphine or methadone are recommended as first-line therapy, with phenobarbital or clonidine as second-line adjunctive therapy. Further research is needed to determine best practices for assessment, nonpharmacologic intervention, and pharmacologic management of infants with NAS in order to improve outcomes.