Sublingual buprenorphine for treatment of neonatal abstinence syndrome: a randomized trial

Babies breaking bad: neonatal and iatrogenic withdrawal syndromes

PURPOSE OF REVIEW

This review will summarize the symptoms, evaluation, and treatment of neonatal and iatrogenic withdrawal syndromes.

RECENT FINDINGS

Buprenorphine is emerging as the drug of choice for maintaining opioid-dependent women during pregnancy, because of its association with less severe withdrawal symptoms. Recent findings suggest it may be the drug of choice for treating the opioid-exposed neonate as well.

SUMMARY

Healthcare workers should be cognizant of the risk factors for neonatal abstinence syndrome (NAS), as well as its symptoms, so that nonpharmalogic and pharmacologic therapies can be initiated. With increased emphasis on pain control in children, it is likely that iatrogenic withdrawal will continue to be a concern, and healthcare workers should understand the similarities and differences between this and NAS.

Pharmacologic management of the opioid neonatal abstinence syndrome

Opioid use in pregnant women has increased over the last decade. Following birth, infants with in utero exposure demonstrate signs and symptoms of withdrawal known as the neonatal abstinence syndrome (NAS). Infants express a spectrum of disease, with most requiring the administration of pharmacologic therapy to ensure proper growth and development. Treatment often involves prolonged hospitalization. There is a general lack of high-quality clinical trial data to guide optimal therapy, and significant heterogeneity in treatment approaches. Emerging trends in the treatment of infants with NAS include the use of sublingual buprenorphine, transition to outpatient therapy, and pharmacogenetic risk stratification.

Formulation of buprenorphine for sublingual use in neonates

OBJECTIVES

The only medication used sublingually in the neonate is buprenorphine for the treatment of neonatal abstinence syndrome (NAS). Compared with morphine, buprenorphine reduces the length of treatment and length of hospitalization in neonates treated for NAS. The objective of this study was to characterize the stability of ethanolic buprenorphine for sublingual administration.

METHODS

Buprenorphine solution was prepared and stored in amber glass source bottles at either 68°F to 77°F (20°C-25°C) or 36°F to 46°F (2.2°C-7.8°C). Samples were collected from each of these batches on days 0, 3, 7, 14, and 30. Additional samples were withdrawn at baseline from each batch and placed in oral dispensing syringes for 3 and 7 days. Buprenorphine concentration was assessed by liquid chromatography-electrospray ionization-tandem mass spectrometry.

RESULTS

Neither storage temperature (p=0.65) nor storage time (p=0.24) significantly affected buprenorphine concentrations. All of the mean concentrations, regardless of storage temperature, were above 95% of the labeled concentration, and the potency was maintained for samples stored either in the original amber glass source bottles or in oral syringes.

CONCLUSIONS

An ethanolic buprenorphine solution is stable at room temperature for 30 days.

Buprenorphine: a newer drug for treating neonatal abstinence syndrome

Neonates may be exposed to various legal and illicit substances during gestation, including cigarettes, alcohol, narcotics, benzodiazepines, antidepressants, and stimulants. Many of these substances can result in varying degrees of drug withdrawal after delivery. Polysubstance use can complicate the clinical evaluation of a newborn both in terms of assessment of withdrawal and treatment of symptoms. For the purpose of this column, the focus is on those infants with in utero narcotic exposure. The primary circumstances under which pregnant women use narcotics are illicit drug abuse, prescribed narcotic maintenance as treatment for abuse, and treatment of chronic pain conditions.

Ineffective morphine treatment regimen for the control of Neonatal Abstinence Syndrome in buprenorphine- and methadone-exposed infants

This study aimed to determine if morphine is effective in ameliorating Neonatal Abstinence Syndrome (NAS) symptoms to non-opioid-exposed control levels in methadone- and buprenorphine-exposed infants. A prospective, non-randomized comparison study with flexible dosing was undertaken in a large teaching maternity hospital in Australia. Twenty-five infants in the groups of buprenorphine-, methadone- and control non-opioid-exposed infants were compared (totaln= 75 infants). Oral morphine sulphate (1 mg/ml) was administered every 4 h to opioid agonist-exposed infants. Modified Finnegan Withdrawal Scale (MFWS) scores determined dosing: score of 8–10: 0.5 mg/kg/day, 11–13: 0.7 mg/kg/day and 14+: 0.9 mg/kg/day. Withdrawal score, amount of morphine administered and length of hospital stay, were used to assess NAS over a 4-week follow-up period. No controls achieved a score higher than 7 on the MFWS. There was no significant difference in the percentage of infants requiring treatment between methadone (60%) and buprenorphine (48%) infants. For treated infants, significantly (P< 0.01) more morphine was administered to methadone (40.07 ± 3.95 mg) compared with buprenorphine infants (22.77 ± 4.29 mg) to attempt to control NAS. Following treatment initiation, significantly more (P< 0.01) methadone (87%) compared with buprenorphine infants (42%) continued to exceed scoring thresholds for morphine treatment requirement, and non-opioid-exposed control infant scores. For treated infants, there was no significant difference in length of hospital stay between methadone and buprenorphine infants. Morphine treatment was not entirely effective in ameliorating NAS to non-opioid-exposed control symptom levels in methadone or buprenorphine infants. The regimen may be less effective in methadone compared with buprenorphine infants.

Neonatal drug withdrawal

Maternal use of certain drugs during pregnancy can result in transient neonatal signs consistent with withdrawal or acute toxicity or cause sustained signs consistent with a lasting drug effect. In addition, hospitalized infants who are treated with opioids or benzodiazepines to provide analgesia or sedation may be at risk for manifesting signs of withdrawal. This statement updates information about the clinical presentation of infants exposed to intrauterine drugs and the therapeutic options for treatment of withdrawal and is expanded to include evidence-based approaches to the management of the hospitalized infant who requires weaning from analgesics or sedatives.

Update on the pharmacologic management of neonatal abstinence syndrome

Although a statement on Neonatal Drug Withdrawal was published in 1998 by the American Academy of Pediatrics, pharmacologic management of neonatal abstinence syndrome (NAS) remains a challenge. Published clinical trials are limited, restricting treatment decision making to practitioner's experience and preference rather than evidence-based medicine. To optimize withdrawal symptom prevention, drug selection is often based on the offending agent (opioids versus polysubstance exposure), clinical presentation, mechanism of action (agonist versus partial agonist/antagonist, receptor effects), pharmacokinetic parameters and available drug formulations. This review addresses risk factors and pathophysiology of NAS, summarizes parameters of common drugs used for the management of NAS, and reviews published literature of standard therapies as well as newer agents. Based on the current literature, paregoric is no longer recommended and oral morphine solutions remain the mainstay of therapy for opiate withdrawal. Other potential therapies include methadone, buprenorphine, phenobarbital and clonidine with the latter two agents as adjunctive therapies.

Development and validation of a method for the determination of buprenorphine and norbuprenorphine in breast milk by gas chromatography-mass spectrometry

Buprenorphine (BUP) is used for the maintenance of opioid-addicted pregnant women. Because BUP and its main metabolite nor-BUP are excreted into breast milk, a sensitive and specific GC/MS method has been developed, optimized and validated for their determination in breast milk. BUP-d4 was used as internal standard. The sample preparation includes combination of protein precipitation with solid-phase extraction and derivatization (acetylation). The absolute recovery for both analytes was found to be higher than 87.3%. The limits of detection and quantification were 0.07 and 0.20 µg/L, respectively. The calibration curves were linear within the dynamic range 0.20-20.0 µg/L, with a correlation coefficient higher than 0.996. Intra- and inter-day accuracies were ranged from -7.06 to 4.50 and from -5.88 to 7.00%, respectively, while intra- and inter-day precision were less than 5.7 and 6.1%. The analytes were found to be stable in breast milk at 4 °C for one week, at -20 °C for one month, and after three freeze-thaw cycles. The method can be used for the determination of BUP and nor-BUP in breast milk of BUP-maintained mothers, in order to calculate the amount of drug that could pass to the newborn via breast milk and to avoid toxic consequences of breastfeeding.

Tolerance and addiction; the patient, the parent or the clinician?

Tolerance has been recognized for some time where chronic exposure to certain drugs, particularly benzodiazepines and opioids, is associated with apparent tachyphylaxis. When these drugs are stopped or progressively reduced as in 'tapering', withdrawal symptoms may result. Tolerance and the flip side of the coin, withdrawal, are the determinants of addiction. It is increasingly apparent that tolerance can occur acutely, even within the time span of a single anesthetic for a surgical procedure. Addiction is caused by agents, foreign to the body, that provoke adaptation by homeostatic biological processes. When these agents are withdrawn, the adaptive mechanisms, devoid of substrate, take time to diminish and produce symptoms recognizable under the term of 'withdrawal'. Children may be exposed to these agents in different ways; in utero, as a result of substances that the mother ingests by enteral, parenteral or inhalational means that are transmitted to the infant via the placenta; as a result of an anesthetic for surgery; or as a result of sedation and analgesia administered to offset the stresses and trauma inherent from intensive care treatment in the neonatal intensive care unit or pediatric intensive care unit. Additionally, anesthetic and intensive care staff are exposed to powerful and addictive drugs as part of everyday practice, not simply by overt access, but also by subliminal environmental exposure.

The World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for the biological treatment of substance use and related disorders. Part 2: Opioid dependence

OBJECTIVES

To develop evidence-based practice guidelines for the pharmacological treatment of opioid abuse and dependence.

METHODS

An international task force of the World Federation of Societies of Biological Psychiatry (WFSBP) developed these practice guidelines after a systematic review of the available evidence pertaining to the treatment of opioid dependence. On the basis of the evidence, the Task Force reached a consensus on practice recommendations, which are intended to be clinically and scientifically meaningful for physicians who treat adults with opioid dependence. The data used to develop these guidelines were extracted primarily from national treatment guidelines for opioid use disorders, as well as from meta-analyses, reviews, and publications of randomized clinical trials on the efficacy of pharmacological and other biological treatments for these disorders. Publications were identified by searching the MEDLINE database and the Cochrane Library. The literature was evaluated with respect to the strength of evidence for efficacy, which was categorized into one of six levels (A-F).

RESULTS

There is an excellent evidence base supporting the efficacy of methadone and buprenorphine or the combination of buprenorphine and naloxone for the treatment of opioid withdrawal, with clonidine and lofexidine as secondary or adjunctive medications. Opioid maintenance with methadone and buprenorphine is the best-studied and most effective treatment for opioid dependence, with heroin and naltrexone as second-line medications.

CONCLUSIONS

There is enough high quality data to formulate evidence-based guidelines for the treatment of opioid abuse and dependence. This task force report provides evidence for the efficacy of a number of medications to treat opioid abuse and dependence, particularly the opioid agonists methadone or buprenorphine. These medications have great relevance for clinical practice.

Buprenorphine TTS for children--a review of the drug's clinical pharmacology

OBJECTIVE

The transdermal therapeutic system (TTS) with buprenorphine is currently being used 'off-label' to treat chronic pediatric pain. We compiled available pharmacokinetic (PK), pharmacodynamic (PD), and clinical pediatric data on buprenorphine to rationalize treatment regimens.

METHODS

We conducted a systematic biomedical literature review focusing on pediatric buprenorphine data.

RESULTS

There are few relevant pediatric buprenorphine data, particularly in children suffering chronic pain. There are no pediatric PK and PD data for children with chronic pain given sublingual or TTS formulations. Children given single dose buprenorphine have increased drug clearance referenced to bodyweight with a possible paradoxical longer duration of action. Buprenorphine metabolism is independent of renal function, which is advantageous in renal insufficiency. The risk of respiratory depression after buprenorphine is difficult to quantify. A concentration-response relationship for respiratory effects has not been described and it is unknown whether children have a ceiling effect similar to that described in healthy adult volunteers.

CONCLUSIONS

Buprenorphine is of interest in pediatric postoperative pain and cancer pain control because of its multiple administration routes, long duration of action, and metabolism largely independent of renal function. There is little reason to expect buprenorphine effects in children out of infancy are fundamentally different to those in adults. From the limited pediatric data available, it appears that buprenorphine has no higher adverse potential than the more commonly used opioids. There is an urgent need for focused PK, PD, and safety studies in children before use in children becomes more widespread.

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

AIMS

More than half of infants exposed to opioids in utero develop neonatal abstinence syndrome (NAS) of severity to require pharmacological therapy. Current treatments are associated with prolonged hospitalization. We sought to optimize the dose of sublingual buprenorphine in the treatment of NAS.

DESIGN

Randomized, Phase 1, open-label, active-control clinical trial comparing sublingual buprenorphine to oral morphine.

SETTING

Large, urban, tertiary care hospital.

PARTICIPANTS

Twenty-four term infants requiring pharmacological treatment for NAS.

MEASUREMENTS

Outcomes were neonatal safety, length of treatment and length of hospitalization.

FINDINGS

Sublingual buprenorphine was safe and effective. Infants treated with buprenorphine had a 23-day length of treatment compared to 38 days for those treated with morphine (P = 0.01), representing a 40% reduction. Length of hospital stay in the buprenorphine group was reduced 24%, from 42 to 32 days (P = 0.05).

CONCLUSIONS

Sublingual buprenorphine was safe in NAS, with a substantial efficacy advantage over standard of care therapy with oral morphine.

Maternal and neonatal factors impacting response to methadone therapy in infants treated for neonatal abstinence syndrome

OBJECTIVE

To identify maternal and neonatal factors that impact response to methadone therapy for neonatal abstinence syndrome.

STUDY DESIGN

This is a retrospective review of 128 infants that received pharmacotherapy for opiate withdrawal to identify factors associated with favorable response to methadone therapy. Maternal and neonatal data were analyzed with univariate statistics and multivariate logistic regression.

RESULT

Maternal methadone maintenance dose during pregnancy correlated with length of stay (P=0.009). There was an inverse correlation between the amount of mother's breast milk ingested and length of stay (β=-0.03, P=0.02). Methadone was initiated later, tapered more rapidly and was more successful as monotherapy in preterm infants. Five percent of infants were admitted to hospital again for rebound withdrawal following reduction of breast milk intake.

CONCLUSION

Severity of neonatal abstinence syndrome may be mitigated by titrating methadone to the lowest effective dose during pregnancy and by encouraging breast milk feeds, which should be weaned gradually.

Opiate treatment for opiate withdrawal in newborn infants

BACKGROUND

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

OBJECTIVES

To assess the effectiveness and safety of using an opiate compared to a sedative or non-pharmacological treatment for treatment of NAS due to withdrawal from opiates.

SEARCH STRATEGY

The review was updated in 2010 with additional searches CENTRAL, MEDLINE and EMBASE supplemented by searches of conference abstracts and citation lists of published articles.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of opiate treatment in infants with NAS born to mothers with opiate dependence.

DATA COLLECTION AND ANALYSIS

Each author assessed study quality and extracted data independently.

MAIN RESULTS

Nine studies enrolling 645 infants met inclusion criteria. There were substantial methodological concerns in all studies comparing an opiate with a sedative. Two small studies comparing different opiates were of good methodology.Opiate (morphine) versus supportive care (one study): A reduction in time to regain birth weight and duration of supportive care and a significant increase in hospital stay was noted.Opiate versus phenobarbitone (four studies): Meta-analysis found no significant difference in treatment failure. One study reported opiate treatment resulted in a significant reduction in treatment failure in infants of mothers using only opiates. One study reported a significant reduction in days treatment and admission to the nursery for infants receiving morphine. One study reported a reduction in seizures, of borderline statistical significance, with the use of opiate.Opiate versus diazepam (two studies): Meta-analysis found a significant reduction in treatment failure with the use of opiate.Different opiates (six studies): there is insufficient data to determine safety or efficacy of any specific opiate compared to another opiate.

AUTHORS' CONCLUSIONS

Opiates compared to supportive care may reduce time to regain birth weight and duration of supportive care but increase duration of hospital stay. When compared to phenobarbitone, opiates may reduce the incidence of seizures but there is no evidence of effect on treatment failure. One study reported a reduction in duration of treatment and nursery admission for infants on morphine. Compared to diazepam, opiates reduce the incidence of treatment failure. A post-hoc analysis generates the hypothesis that initial opiate treatment may be restricted to infants of mothers who used opiates only. In view of the methodologic limitations of the included studies the conclusions of this review should be treated with caution.

Regional Fos expression induced by morphine withdrawal in the 7-day-old rat

Human infants are often exposed to opiates chronically but the mechanisms by which opiates induce dependence in the infant are not well studied. In the adult the brain regions involved in the physical signs of opiate withdrawal include the periaqueductal gray area, the locus coeruleus, amygdala, ventral tegmental area, nucleus accumbens, hypothalamus, and spinal cord. Microinjection studies show that many of these brain regions are involved in opiate withdrawal in the infant rat. Our goal here was to determine if these regions become metabolically active during physical withdrawal from morphine in the infant rat as they do in the adult. Following chronic morphine or saline treatment, withdrawal was precipitated in 7-day-old pups with the opiate antagonist naltrexone. Cells positive for Fos-like immunoreactivity were quantified within select brain regions. Increased Fos-like labeled cells were found in the periaqueductal gray, nucleus accumbens, locus coeruleus, and spinal cord. These are consistent with other studies showing that the neural circuits underlying the physical signs of opiate withdrawal are similar in the infant and adult.

Buprenorphine for opioid dependence

Buprenorphine is a partial mu agonist opioid that is FDA-approved to manage opioid addiction in settings outside of traditional methadone clinics. The clinical uses, pharmacokinetics, pharmacodynamics, toxicology, and management of overdoses of buprenorphine are reviewed.

Substance abuse and child maltreatment

Pediatricians and other medical providers caring for children need to be aware of the dynamics in the significant relationship between substance abuse and child maltreatment. A caregiver's use and abuse of alcohol, marijuana, heroin, cocaine, methamphetamine, and other drugs place the child at risk in multiple ways. Members of the medical community need to understand these risks because the medical community plays a unique and important role in identifying and caring for these children. Substance abuse includes the abuse of legal drugs as well as the use of illegal drugs. The abuse of legal substances may be just as detrimental to parental functioning as abuse of illicit substances. Many substance abusers are also polysubstance users and the compounded effect of the abuse of multiple substances may be difficult to measure. Often other interrelated social features, such as untreated mental illness, trauma history, and domestic violence, affect these families.

The opioid-exposed newborn: assessment and pharmacologic management

The infant exposed to opioids in utero frequently presents a challenge to the neonatal care provider in the assessment and treatment of symptoms of Neonatal Abstinence Syndrome (NAS) after birth. This review is intended to provide the healthcare professional with a brief review of current evidence and practical guidelines for optimal evaluation and pharmacologic management of the opioid-exposed newborn.