Perinatal outcomes of Australian buprenorphine-exposed mothers and their newborn infants

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.

Sedatives 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 a sedative versus control (placebo, usual treatment or non-pharmacological treatment) for NAS due to withdrawal from opioids and determine which type of sedative is most effective and safe for NAS due to withdrawal from opioids.

SEARCH METHODS

We ran an updated search on 17 September 2020 in CENTRAL via CRS Web and MEDLINE via Ovid. We searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

We included trials enrolling infants with NAS born to mothers with an opioid dependence with more than 80% follow-up and using randomised, quasi-randomised and cluster-randomised allocation to sedative or control.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

We included 10 trials (581 infants) with NAS secondary to maternal opioid use in pregnancy. There were multiple comparisons of different sedatives and regimens. There were limited data available for use in sensitivity analysis of studies at low risk of bias. Phenobarbital versus supportive care: one study reported there may be little or no difference in treatment failure with phenobarbital and supportive care versus supportive care alone (risk ratio (RR) 2.73, 95% confidence interval (CI) 0.94 to 7.94; 62 participants; very low-certainty evidence). No infant had a clinical seizure. The study did not report mortality, neurodevelopmental disability and adverse events. There may be an increase in days' hospitalisation and treatment from use of phenobarbital (hospitalisation: mean difference (MD) 20.80, 95% CI 13.64 to 27.96; treatment: MD 17.90, 95% CI 11.98 to 23.82; both 62 participants; very low-certainty evidence). Phenobarbital versus diazepam: there may be a reduction in treatment failure with phenobarbital versus diazepam (RR 0.39, 95% CI 0.24 to 0.62; 139 participants; 2 studies; low-certainty evidence). The studies did not report mortality, neurodevelopmental disability and adverse events. One study reported there may be little or no difference in days' hospitalisation and treatment (hospitalisation: MD 3.89, 95% CI -1.20 to 8.98; 32 participants; treatment: MD 4.30, 95% CI -0.73 to 9.33; 31 participants; both low-certainty evidence). Phenobarbital versus chlorpromazine: there may be a reduction in treatment failure with phenobarbital versus chlorpromazine (RR 0.55, 95% CI 0.33 to 0.92; 138 participants; 2 studies; very low-certainty evidence), and no infant had a seizure. The studies did not report mortality and neurodevelopmental disability. One study reported there may be little or no difference in days' hospitalisation (MD 7.00, 95% CI -3.51 to 17.51; 87 participants; low-certainty evidence) and 0/100 infants had an adverse event. Phenobarbital and opioid versus opioid alone: one study reported no infants with treatment failure and no clinical seizures in either group (low-certainty evidence). The study did not report mortality, neurodevelopmental disability and adverse events. One study reported there may be a reduction in days' hospitalisation for infants treated with phenobarbital and opioid (MD -43.50, 95% CI -59.18 to -27.82; 20 participants; low-certainty evidence). Clonidine and opioid versus opioid alone: one study reported there may be little or no difference in treatment failure with clonidine and dilute tincture of opium (DTO) versus DTO alone (RR 0.09, 95% CI 0.01 to 1.59; 80 participants; very low-certainty evidence). All five infants with treatment failure were in the DTO group. There may be little or no difference in seizures (RR 0.14, 95% CI 0.01 to 2.68; 80 participants; very low-certainty evidence). All three infants with seizures were in the DTO group. There may be little or no difference in mortality after discharge (RR 7.00, 95% CI 0.37 to 131.28; 80 participants; very low-certainty evidence). All three deaths were in the clonidine and DTO group. The study did not report neurodevelopmental disability. There may be little or no difference in days' treatment (MD -4.00, 95% CI -8.33 to 0.33; 80 participants; very low-certainty evidence). One adverse event occurred in the clonidine and DTO group. There may be little or no difference in rebound NAS after stopping treatment, although all seven cases were in the clonidine and DTO group. Clonidine and opioid versus phenobarbital and opioid: there may be little or no difference in treatment failure (RR 2.27, 95% CI 0.98 to 5.25; 2 studies, 93 participants; very low-certainty evidence). One study reported one infant in the clonidine and morphine group had a seizure, and there were no infant mortalities. The studies did not report neurodevelopmental disability. There may be an increase in days' hospitalisation and days' treatment with clonidine and opioid versus phenobarbital and opioid(hospitalisation: MD 7.13, 95% CI 6.38 to 7.88; treatment: MD 7.57, 95% CI 3.97 to 11.17; both 2 studies, 91 participants; low-certainty evidence). There may be little or no difference in adverse events (RR 1.55, 95% CI 0.44 to 5.40; 2 studies, 93 participants; very low-certainty evidence). However, there was oversedation only in the phenobarbital and morphine group; and hypotension, rebound hypertension and rebound NAS only in the clonidine and morphine group.

AUTHORS' CONCLUSIONS

There is very low-certainty evidence that phenobarbital increases duration of hospitalisation and treatment, but reduces days to regain birthweight and duration of supportive care each day compared to supportive care alone. There is low-certainty evidence that phenobarbital reduces treatment failure compared to diazepam and very low-certainty evidence that  phenobarbital reduces treatment failure compared to chlorpromazine. There is low-certainty evidence of an increase in days' hospitalisation and days' treatment with clonidine and opioid compared to phenobarbital and opioid. There are insufficient data to determine the safety and incidence of adverse events for infants treated with combinations of opioids and sedatives including phenobarbital and clonidine.

Factors Associated With the Need for Pharmacological Management of Neonatal Opioid Withdrawal Syndrome

BACKGROUND

Neonatal opioid withdrawal syndrome (NOWS) is a significant and growing health problem that affects more than 23,000 infants annually, with an estimated hospital cost of more than $720 million.

PURPOSE

The purpose of this study was to examine factors associated with the need to initiate medication for the treatment of NOWS.

METHODS

A retrospective review of medical records was conducted of 204 infants born to mothers who used opioids during pregnancy from April 2011 to September 2017. Associations between maternal, infant, and environmental factors and the need for neonatal pharmacological management were examined using χ, t tests, and regression analysis.

RESULTS

Of 204 neonates exposed to opioids prenatally, 121 (59%) developed symptoms of NOWS, requiring treatment with morphine. Neonates requiring morphine had significantly higher gestational ages (37.7 weeks vs 36.4 weeks; P < .001), and mothers were present at the neonate's bedside for a lower proportion of their total hospital stay (57% vs 74% of days; P < .001). Maternal factors associated with the need for neonatal medication treatment included the mother's reason for opioid use (P = .014), primary type of opioid used (P < .001), tobacco use (P = .023), and use of benzodiazepines (P = .003).

IMPLICATIONS FOR PRACTICE

This research provides information regarding the proportion of infants exposed to opioids prenatally who develop NOWS that requires treatment, as well as maternal, infant, and environmental factors associated with the need for neonatal medication use.

IMPLICATIONS FOR RESEARCH

Future research is needed to examine these relationships prospectively in a larger and more diverse sample.

Prevalence of substance use disorder and psychiatric comorbidity burden among pregnant women with opioid use disorder in a large administrative database, 2009-2014

Objectives: Using data from the Healthcare Cost and Utilization Project (HCUP), we estimated prevalence of individual substance use disorders (SUDs) and psychiatric comorbidities among pregnant women with opioid use disorder (OUD) in the New York State from 2009 to 2014.Methods: In this cross-sectional study, pregnancy outcome and gestational age at delivery were estimated, and OUD diagnosis during pregnancy or at delivery discharge was identified. Prevalence of SUDs and psychiatric comorbidities were then calculated.Results: Among 1,463,302 pregnant women, 8324 (0.57%) were diagnosed with OUD during pregnancy or at delivery. The most frequent SUDs or psychiatric comorbidities among pregnant women with OUD were non-opioid SUD (78.2%), followed by tobacco use disorder (74.9%), generalized anxiety disorder (38.0%), major depressive disorder (36.9%), cannabis use disorder (28.3%) and cocaine use disorder (27.4%).Conclusions: Most pregnant women with OUD were diagnosed with at least one non-opioid SUD and tobacco use disorder. Generalized anxiety disorder and major depressive disorder were also common, suggesting that mental health screenings should be prioritized for pregnant women with OUD.

Short-term health outcomes of newborn infants of substance-using mothers in Australia and New Zealand: A systematic review

AIM

Substance use is not unusual among women of childbearing age. Pregnant women who use a substance and the consequent impacts on a newborn vary across studies and settings. We reviewed New Zealand and Australian literature to examine the short-term health outcomes of newborn of substance-using mothers and their demographic characteristics.

METHODS

Five medical/nursing databases and google scholar were searched in April 2017. Studies were considered eligible if they described outcomes of newborn of substance-using mothers. Mixed Methods Appraisal Tool was used for quality assessment of candidate studies. Relevant data were extracted and analyzed using narrative synthesis. Based on data availability, a subset of studies was included in meta-analysis.

RESULTS

Although findings of individual studies vary, there are some evidence that the infants born to substance-using mothers were likely to have preterm birth, low birthweight, small-for-gestational age, low Apgar score, and admission to neo-natal intensive care unit. The likelihood of adverse health outcomes was much higher for newborns of polysubstance-using mothers, than newborns of mothers using a single substance. Pregnant women who use illicit substance are predominantly socially disadvantaged, in their twenties and or of Aboriginal descent.

CONCLUSION

Infants of substance-using mothers suffer a range of adverse health outcomes. Multidisciplinary and integrated approach of services that ensure supportive social determinants of health may result in a better outcome for newborn and positive behavioral change among mothers.

Opium use during pregnancy and infant size at birth: a cohort study

BACKGROUND

The reported positive association between opiatic drug use during pregnancy and adverse pregnancy outcomes might be confounded by other factors related to high-risk behaviors, including the use of other harmful substances. In rural areas of Iran, opium use during pregnancy is relatively common among women who otherwise do not have a hazardous lifestyle, which reduces the risk of residual confounding and increasing the possibility to identify its effects. We aimed to examine the association of antenatal exposure to opium with risks of small for gestational age, short birth length, and small head circumference at birth.

METHOD

In this cohort study in the rural area of the Golestan province, Iran, we randomly selected 920 women who were exposed to opium during pregnancy and 920 unexposed women during 2008-2010. Log-binomial regression was used to estimate risk ratios (RR) and 95% confidence intervals (CI) for the associations between prenatal exposure to opium and risks of small for gestational age, short birth length, and small head circumference at birth.

RESULTS

Compared with non-use of opium and tobacco during pregnancy, using opium only and dual use of opium and tobacco were associated with increased risks of small for gestational age at births (RR = 1.71; 95% CI 1.34-2.18 and RR = 1.62; 95% CI 1.13-2.30, respectively). Compared with non-use of opium and tobacco, exposure to only opium or dual use of opium and tobacco were also associated with more than doubled increased risks of short birth length, and small head circumference in term infants.

CONCLUSION

Maternal opium use during pregnancy is associated with increased risks of giving birth to a small for gestational age infant, as well as a term infant with short birth length or small head circumference.

Expression of kappa opioid receptors in developing rat brain - Implications for perinatal buprenorphine exposure

Buprenorphine, a mu opioid receptor partial agonist and kappa opioid receptor (KOR) antagonist, is an emerging therapeutic agent for maternal opioid dependence in pregnancy and neonatal abstinence syndrome. However, the endogenous opioid system plays a critical role in modulating neurodevelopment and perinatal buprenorphine exposure may detrimentally influence this. To identify aspects of neurodevelopment vulnerable to perinatal buprenorphine exposure, we defined KOR protein expression and its cellular associations in normal rat brain from embryonic day 16 to postnatal day 23 with double-labelling immunohistochemistry. KOR was expressed on neural stem and progenitor cells (NSPCs), choroid plexus epithelium, subpopulations of cortical neurones and oligodendrocytes, and NSPCs and subpopulations of neurones in postnatal hippocampus. These distinct patterns of KOR expression suggest several pathways vulnerable to perinatal buprenorphine exposure, including proliferation, neurogenesis and neurotransmission. We thus suggest the cautious use of buprenorphine in both mothers and infants until its impact on neurodevelopment is better defined.

Maternal substance use and child protection: a rapid evidence assessment of factors associated with loss of child care

This article reviews the literature on the factors associated with mothers who use substances losing care of their children. A rapid evidence assessment was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta Analyses. Medline and PsycINFO databases were searched to identify primary research studies published in English during January 2000-September 2016. Studies were included if they presented individual, formal support (e.g., receiving substance use treatment) or informal support (e.g., receiving social and family support) factors associated with mothers who use substances retaining or losing care of their child/ren (losing care refers to child protection services placing child/ren under the custody of a family relative, foster care, child care institution, or adoption). Evaluation studies or trials of interventions were excluded as were studies that focused on reunification or re-entering care as the outcome. Thirteen studies were included. Factors associated with mothers who use substances losing care of their children included: maternal characteristics (low socioeconomic status, younger age of first child, criminal justice involvement); psychological factors (mental health co-morbidity, adverse childhood experiences); patterns of substance use (use of cocaine prenatally, injection drug use); formal and informal support (not receiving treatment for substance use, fewer prenatal care visits, lack of social support). There is not enough evidence to determine the influence of substance use treatment in preventing mothers losing care of their children. Factors identified in this review provide the evidence to inform a prevention agenda and afford services the opportunity to design interventions that meet the needs of those mothers who are more likely to lose care of their children.

Psychiatric Co-Morbidities in Pregnant Women with Opioid Use Disorders: Prevalence, Impact, and Implications for Treatment

Purpose of Review

This review seeks to investigate three questions: What is the prevalence of comorbid psychiatric diagnoses among pregnant women with opioid use disorder (OUD)? How do comorbid psychiatric illnesses impact pregnant women with OUD? And how do comorbid psychiatric illnesses affect the ability of pregnant women with OUD to adhere to and complete OUD treatment?

Recent Findings

Based on this literature review, 25–33% of pregnant women with OUD have a psychiatric comorbidity, with depression and anxiety being especially common. However, of the 17 studies reviewed only 5 have prevalence rates of dual diagnosis in pregnant women with OUD as their primary outcome measures, their N’s were typically small, methods for determining psychiatric diagnosis were variable, and many of the studies were undertaken with women presenting for treatment which carries with its implicit selection bias. Of the women enrolled in treatment programs for SUD, those with psychiatric comorbidity were more likely to have impaired psychological and family/social functioning than those without psychiatric comorbidity. Greater severity of comorbid psychiatric illness appears to predict poorer adherence to treatment, but more research is needed to clarify this relationship with the psychiatric illness is less severe.

Summary

While cooccurrence of psychiatric disorders in pregnant women with opioid use disorder appears to be common, large population-based studies with validated diagnostic tools and longitudinal assessments are needed to obtain definitive rates and characteristics of cooccurring illnesses. Integrated prenatal, addiction, and psychiatric treatment in a setting that provides social support to pregnant patients with OUD is most effective in maintaining women in treatment. More research is still needed to identify optimal treatment settings, therapy modalities, and medication management for dually diagnosed pregnant women with OUD.

Predictors of neonatal abstinence syndrome in buprenorphine exposed newborn: can cord blood buprenorphine metabolite levels help?

BACKGROUND

Buprenorphine is a semi-synthetic opioid used for the treatment of opioid dependence. Opioid use, including buprenorphine, has been increasing in recent years, in the general population and in pregnant women. Consequently, there has been a rise in frequency of neonatal abstinence syndrome (NAS), associated with buprenorphine use during pregnancy. The purpose of this study was to investigate correlations between buprenorphine and buprenorphine-metabolite concentrations in cord blood and onset of NAS in buprenorphine exposed newborns.

METHODS

Nineteen (19) newborns who met inclusion criteria were followed after birth until discharge in a double-blind non-intervention study, after maternal consent. Cord blood and tissue samples were collected and analyzed by liquid chromatography-mass spectrometry (LC-MS) for buprenorphine and metabolites. Simple and multiple logistic regressions were used to examine relationships between buprenorphine and buprenorphine metabolite concentrations in cord blood and onset of NAS, need for morphine therapy, and length of stay.

RESULTS

Each increase in 5 ng/ml level of norbuprenorphine in cord blood increases odds of requiring treatment by morphine 2.5 times. Each increase in 5 ng/ml of buprenorphine-glucuronide decreases odds of receiving morphine by 57.7 %. Along with concentration of buprenorphine metabolites, birth weight and gestational age also play important roles, but not maternal buprenorphine dose.

CONCLUSIONS

LC-MS analysis of cord blood concentrations of buprenorphine and metabolites is an effective way to examine drug and metabolite levels in the infant at birth. Cord blood concentrations of the active norbuprenorphine metabolite and the inactive buprenorphine-glucuronide metabolite show promise in predicting necessity of treatment of NAS. These finding have implications in improving patient care and reducing healthcare costs if confirmed in a larger sample.

Endogenous opiates and behavior: 2014

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).

Neonatal abstinence syndrome

Neonatal abstinence syndrome (NAS) is a result of the sudden discontinuation of fetal exposure to substances that were used or abused by the mother during pregnancy. Withdrawal from licit or illicit substances is becoming more common among neonates in both developed and developing countries. NAS continues to be an important clinical entity throughout much of the world. NAS leads to a constellation of signs and symptoms involving multiple systems. The pathophysiology of NAS is not completely understood. Urine or meconium confirmation may assist the diagnosis and management of NAS. The Finnegan scoring system is commonly used to assess the severity of NAS; scoring can be helpful for initiating, monitoring, and terminating treatment in neonates. Nonpharmacological care is the initial treatment option, and pharmacological treatment is required if an improvement is not observed after nonpharmacological measures or if the infant develops severe withdrawal. Morphine is the most commonly used drug in the treatment of NAS secondary to opioids. An algorithmic approach to the management of infants with NAS is suggested. Breastfeeding is not contraindicated in NAS, unless the mother is taking street drugs, is involved in polydrug abuse, or is infected with HIV. Future studies are required to assess the long-term effects of NAS on children after prenatal exposure.