Concentrations of methadone in breast milk and plasma in the immediate perinatal period

Monitoring Prenatal Exposure to Buprenorphine and Methadone

PURPOSE

Buprenorphine and methadone are international gold standards for managing opioid use disorders. Although they are efficacious in treating opioid dependence, buprenorphine and methadone present risks, especially during pregnancy, causing neonatal abstinence syndrome and adverse obstetrical outcomes. Buprenorphine and methadone are also abused during pregnancy, and identifying their use is important to limit unprescribed prenatal exposure. Previous studies have suggested that concentrations of buprenorphine, but not methadone markers in unconventional matrices may predict child outcomes, although currently only limited data exist. We reviewed the literature on concentrations of buprenorphine, methadone, and their metabolites in unconventional matrices to improve data interpretation.

METHODS

A literature search was conducted using scientific databases (PubMed, Scopus, Web of Science, and reports from international institutions) to review published articles on buprenorphine and methadone monitoring during pregnancy.

RESULTS

Buprenorphine and methadone and their metabolites were quantified in the meconium, umbilical cord, placenta, and maternal and neonatal hair. Methadone concentrations in the meconium and hair were typically higher than those in other matrices, although the concentrations in the placenta and umbilical cord were more suitable for predicting neonatal outcomes. Buprenorphine concentrations were lower and required sensitive instrumentation, as measuring buprenorphine glucuronidated metabolites is critical to predict neonatal outcomes.

CONCLUSIONS

Unconventional matrices are good alternatives to conventional ones for monitoring drug exposure during pregnancy. However, data are currently scarce on buprenorphine and methadone during pregnancy to accurately interpret their concentrations. Clinical studies should be conducted with larger cohorts, considering confounding factors such as illicit drug co-exposure.

High Accumulation of Methadone Compared with Buprenorphine in Fetal Rat Brain after Maternal Exposure

Experimental animal studies are valuable in revealing a causal relationship between prenatal exposure to opioid maintenance treatment (OMT) and subsequent effects; however, previous animal studies of OMT during pregnancy have been criticized for their lack of clinical relevance because of their use of high drug doses and the absence of pharmacokinetic data. Hence, the aim of this study was to determine blood and brain concentrations in rat dams, fetuses, and offspring after continuous maternal exposure to methadone or buprenorphine during gestation and to examine the offspring for neonatal outcomes and withdrawal symptoms. Female rats were implanted with a 28-day osmotic minipump delivering methadone (10 mg/kg per day), buprenorphine (1 mg/kg per day) or vehicle 5 days before mating. Continuous exposure to methadone or buprenorphine induced stable blood concentrations in the dams of 0.25 ± 0.02 µM and 5.65 ± 0.16 nM, respectively. The fetal brain concentration of methadone (1.89 ± 0.35 nmol/g) was twice as high as that in the maternal brain, whereas the fetal brain concentration of buprenorphine (20.02 ± 4.97 pmol/g) was one-third the maternal brain concentration. The opioids remained in the offspring brain several days after the exposure ceased. Offspring prenatally exposed to methadone, but not buprenorphine, displayed reduced body weight and length and increased corticosterone levels. No significant changes in ultrasonic vocalizations were revealed. Our data in rat fetuses and neonates indicate that OMT with buprenorphine may be a better choice than methadone during pregnancy. SIGNIFICANCE STATEMENT: Concern has been raised about the use of opioid maintenance treatment during pregnancy because of the important role of the endogenous opioid system in brain development. Here, we show that the methadone concentration in the fetal rat brain was twice as high as that in the maternal brain, whereas the buprenorphine concentration was one-third the maternal concentration. Furthermore, buprenorphine allowed more favorable birth outcomes, suggesting that buprenorphine may be a better choice during pregnancy.

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.

The Association Between Breastfeeding and Length of Hospital Stay Among Infants Diagnosed with Neonatal Abstinence Syndrome: A Population-Based Study of In-Hospital Births

OBJECTIVE

The incidence of neonatal abstinence syndrome (NAS), a drug withdraw syndrome mainly associated with intrauterine opioid exposure, has increased considerably in the United States since 2000. Nonpharmacological options, including breastfeeding, may be effective at improving outcomes in this population. The objective of this population-based study was to examine the association between breastfeeding and length of hospital stay among infants diagnosed with NAS.

METHODS

This was a retrospective cohort study of singleton in-hospital births to resident mothers in Pennsylvania. Hospital discharge data from births occurring between 2012 through 2014 were linked with corresponding birth certificate data. International Classification of Diseases, Ninth Revision, Clinical Modification discharge diagnosis codes were used to identify NAS neonates (N = 3,725). Breastfeeding at discharge was used to determine breastfeeding status. Infant and maternal characteristics were compared by breastfeeding status and the association between breastfeeding and infant length of hospitalization was assessed.

RESULTS

Less than one-half of infants diagnosed with NAS were breastfed at discharge. Significant differences in infant birth weight and gestational age, and maternal education, marital status, prenatal care, smoking, and insurance status were found by breastfeeding status. A significant inverse relationship existed between breastfeeding and hospital length of stay for infants diagnosed with NAS. Specifically, length of hospitalization was reduced by 9.4% in the breastfed group compared to the nonbreastfed group.

CONCLUSION

Breastfeeding may be beneficial for infants diagnosed with NAS by shortening the length of hospital stay. Future prospective studies are warranted to further examine the benefits of breastfeeding and other nonpharmaceutical interventions in NAS populations.

Breastfeeding and Opiate Substitution Therapy: Starting to Understand Infant Feeding Choices

INTRODUCTION

Despite research demonstrating the safety and benefit of breastfeeding in opioid substitution therapy, few women in treatment breastfeed. Understanding the factors contributing to the choices women on opioid substitution therapy make about infant feeding is important.

OBJECTIVES

The aim of this study was to better understand and support infant feeding choices and breastfeeding experiences in women on opioid substitution therapy.

METHODS

A systematic review was conducted on five databases: (1) Ovid MEDLINE(R) without revisions, (2) Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, (3) EMBASE, (4) CINAHL, and (5) FRANCIS. From 1081 articles, 46 articles were reviewed.

RESULTS

The literature supports breastfeeding as an appropriate and safe option for women on opioid substitution treatment. Breastfeeding and rooming-in reduce neonatal abstinence. Women face barriers to breastfeeding due to societal stigma and the lack of patient and health-care provider education.

CONCLUSIONS

Efforts are needed to increase the knowledge that women and health-care professionals have about the safety and benefits of breastfeeding.

Caring for Pregnant Women with Opioid Use Disorder in the USA: Expanding and Improving Treatment

PURPOSE OF THE REVIEW

Opioid use disorder in the USA is rising at an alarming rate, particularly among women of childbearing age. Pregnant women with opioid use disorder face numerous barriers to care, including limited access to treatment, stigma, and fear of legal consequences. This review of opioid use disorder in pregnancy is designed to assist health care providers caring for pregnant and postpartum women with the goal of expanding evidence-based treatment practices for this vulnerable population.

RECENT FINDINGS

We review current literature on opioid use disorder among US women, existing legislation surrounding substance use in pregnancy, and available treatment options for pregnant women with opioid use disorder. Opioid agonist treatment (OAT) remains the standard of care for treating opioid use disorder in pregnancy. Medically assisted opioid withdrawal ("detoxification") is not recommended in pregnancy and is associated with high maternal relapse rates. Extended release naltrexone may confer benefit for carefully selected patients. Histories of trauma and mental health disorders are prevalent in this population; and best practice recommendations incorporate gender-specific, trauma-informed, mental health services. Breastfeeding with OAT is safe and beneficial for the mother-infant dyad.

SUMMARY

Further research investigating options of OAT and the efficacy of opioid antagonists in pregnancy is needed. The US health care system can adapt to provide quality care for these mother-infant dyads by expanding comprehensive treatment services and improving access to care.

Revision of Breastfeeding Guidelines in the Setting of Maternal Opioid Use Disorder: One Institution's Experience

Breastfeeding is recommended for women with opioid use disorder who are treated with methadone or buprenorphine. Infants with neonatal abstinence syndrome (NAS) secondary to in-utero opioid exposure have unique challenges related to breastfeeding but also have significant benefits including improved NAS symptoms with a decreased need for pharmacotherapy. Poor understanding of substance use disorder and treatment, lack of evidence-based recommendations, and vague guidelines from national academies create controversy about breastfeeding eligibility for these women. Defining breastfeeding guidelines is often difficult, particularly in large institutions with multiple providers caring for the mother-infant dyad. Based on the available evidence and review of our institutional data, we revised our breastfeeding guidelines for mothers with opioid use disorder. The aims of our new guidelines are (a) to safely promote breastfeeding in all mothers with opioid use disorder who are in recovery, (b) to improve NAS outcomes through use of breastfeeding as a key nonpharmacologic treatment modality, and (c) to improve staff communication and consistency on the subject of breastfeeding in this patient population.

Advising Mothers on the Use of Medications during Breastfeeding: A Need for a Positive Attitude

The use of medications by the nursing mother is a common reason for interrupting breastfeeding. Few drugs have been demonstrated to be absolutely contraindicated during breastfeeding. Excessive caution may lead health professionals to unnecessarily advise to interrupt breastfeeding, without assessing the latest evidence or considering the risk-benefit ratio of taking a medication versus terminating breastfeeding. To foster an appropriate approach toward the use of medications in breastfeeding women, the Italian Society of Perinatal Medicine created the following policy statement.

Forensic Investigation of Methadone Concentrations in Deceased Breastfed Infants

There is a paucity of data to aid in assessing whether postmortem methadone findings in breastfed infants are clinically and/or toxicologically significant. Two cases are reported in which methadone was detected in deceased neonates whose mothers were enrolled in methadone maintenance programs and were breastfeeding. In addition to a complete autopsy and toxicological testing for alcohol, prescription medications, and drugs of abuse, pharmacogenetic analysis was performed for variants in genes related to methadone metabolism and response. In both cases, the postmortem methadone concentration measured in neonatal heart blood was higher than the maximum serum methadone concentration reported in living breastfed infants whose mothers were receiving methadone. However, additional analysis of antemortem blood indicated postmortem redistribution of methadone. Pharmacogenetic results were suggestive of a potential predisposition to methadone toxicity based on studies in adults; the significance of these findings in breastfed neonates requires further research. The medical cause of death was unascertained in both cases.

Genetic determinants of fetal opiate exposure and risk of neonatal abstinence syndrome: Knowledge deficits and prospects for future research

Opiate-dependent pregnant women receive opiate maintenance medications to prevent illicit use and withdrawal. Fetal opiate exposure causes central nervous system (CNS) alterations which manifest as postnatal physical withdrawal. The extensive variability in the Neonatal Abstinence Syndrome phenotype remains unexplained and may be related to variability in fetal exposure and response. Improved understanding of functionally significant genetic variants in pathways influencing placental opiate transfer and fetal response can lead to personalized maternal therapy and optimized neonatal outcomes.

Development and implementation of a pharmacist-managed, neonatal and pediatric, opioid-weaning protocol

OBJECTIVES

To compare the length of wean and abstinence severity in neonatal and pediatric patients with neonatal abstinence syndrome or iatrogenic opioid dependence treated with a pharmacist-managed, methadone-based protocol compared with physician-managed patients treated with either methadone or dilute tincture of opium (DTO).

METHODS

This was a prospective, single-centered, interventional evaluation of 54 pharmacist-managed patients versus 53 retrospective, physician-managed patients. Wean duration and severity of neonatal abstinence syndrome were compared between groups using the Student t test.

RESULTS

Significantly shorter wean duration in in utero-exposed pharmacist-managed patients compared with patients on physician-managed DTO (11.7 days vs 24.2 days, p < 0.001), but not compared with patients on physician-managed methadone (11.7 days vs 47 days, p = 0.101). No statistically significant difference was seen in wean duration in iatrogenic-exposed pharmacist-managed patients compared with patients on either physician-managed DTO or methadone (8.69 days vs 14 days, p = 0.096) and (8.69 days vs 9.82 days, p = 0.34), respectively. There were significantly fewer abstinence scores >12 in pharmacist-managed patients versus physician-managed DTO, but not physician-managed methadone (2.05 vs 17.3, p = 0.008 and 2.05 vs 74.3, p = 0.119, respectively). Significantly fewer abstinence scores ≥8 × 3 consecutively were seen in pharmacist-managed patients compared with patients on either physician-managed DTO or methadone (2.89 vs 11.9, p = 0.01 and 2.89 vs 24, p < 0.001, respectively).

CONCLUSIONS

Use of a pharmacist-managed, methadone-based weaning protocol standardizes patient care and has the potential to decrease abstinence severity and shorten duration of wean versus physician-managed patients exposed to opioids in utero. Additionally, a methadone wean of 10% to 20% per day was well tolerated in both neonatal and pediatric patients.

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.

Quantitation of methadone and metabolite in patients under maintenance treatment

Gas chromatography-mass spectrometry quantitative method was developed to monitor concentrations of methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in plasma and urine of patients. The developed method was simple, accurate and reproducible to quantify methadone and EDDP in plasma and urine samples in the concentration range of 15-1,000 and 50-2,000 ng/mL, respectively. The proposed analytical method was applied to plasma and urine samples obtained from 96 patients undergoing methadone maintenance treatment (MMT) with daily methadone doses of 2-120 mg/day. Urinary methadone excretion was observed to be significantly affected by pH, in which the ratio of methadone to EDDP was two times higher in acidic urine (P = 0.029). The findings of this study further enhance the guidelines for monitoring of methadone treatment among outpatients. Methadone-to-EDDP ratio in urine was found to be consistent at 24 and 4 h, hence suggesting the possibility that outpatients may be monitored with single urine sample in order to check for compliance. This study which provides data on peak concentrations of methadone and EDDP as well as the ratio of both compounds has added to the body of knowledge regarding pharmacokinetic properties of methadone among heroin-dependent patients under MMT.

Breastfeeding and Methadone Therapy: The Maternal Experience

BACKGROUND

Despite evidence of low transfer of methadone into breast milk and the potential physical and psychological benefits that breastfeeding offers for methadone-exposed mothers and infants, the rate of breastfeeding initiation in this population is about half that reported nationally. This study describes the perceptions surrounding breastfeeding decisions and management among pregnant and postpartum women taking methadone.

METHODS

Seven pregnant women and 4 postpartum women enrolled in methadone maintenance programs participated in semistructured, audiotaped interviews and focus groups, respectively, about their breastfeeding experiences. Transcripts were analyzed and coded using qualitative content analysis.

RESULTS

Three major content categories were identified: (1) fears, barriers, and misconceptions about breastfeeding while taking methadone; (2) motivation and perceived benefits of breastfeeding; and (3) sources of information, support, and anxiety about general breastfeeding management and breastfeeding while taking methadone. Lack of support from the health care community and misinformation about the dangers of combining breastfeeding and methadone therapy represented significant, yet modifiable, barriers to breastfeeding success in methadone-exposed women.

CONCLUSIONS

Interventions to increase the prevalence of breastfeeding among women taking methadone should address identified logistical, educational, and psychological barriers and consider inclusion of women themselves, partners, peers, and clinicians. In particular, clinicians who care for methadone-exposed mothers and infants should be educated on therapeutic communication, up-to-date breastfeeding contraindications, and the health benefits of breastfeeding in this population.

Breastfeeding reduces the need for withdrawal treatment in opioid-exposed infants

AIM

To examine the rate and duration of breastfeeding in a cohort of women in opioid maintenance treatment (OMT) in Norway, as well as the effect of breastfeeding on the incidence and duration of neonatal abstinence syndrome (NAS).

METHODS

A national cohort of 124 women treated with either methadone or buprenorphine during pregnancy, and their neonates born between 1999 and 2009, was evaluated in three study parts. A standardized questionnaire was administered, and medical information from the hospitals and municipalities were collected to confirm self-reported data.

RESULTS

There were high initiation rates of breastfeeding (77%) for women in OMT, but also high rates of early cessation of breastfeeding. Breastfed neonates exposed to methadone prenatally had significantly lower incidence of NAS requiring pharmacotherapy (53% vs. 80%), and both the whole group of infants and the methadone-exposed neonates needed shorter pharmacological treatment of NAS (p < 0.05) than neonates who were not breastfed.

CONCLUSION

Breastfed neonates exposed to OMT medication prenatally, and methadone-exposed newborns in particular, have lower incidence of NAS and require shorter pharmacotherapy for NAS than infants who are not breastfed. The results add to the evidence regarding the benefits of breastfeeding for neonates prenatally exposed to OMT medications.

The relationship between maternal methadone dose at delivery and neonatal outcome: methodological and design considerations

Compared to untreated opioid dependence, methadone maintenance treatment of opioid-dependent pregnant women has been found to be associated with better maternal and neonatal outcomes. Secondary analysis of data from 73 maternal and neonatal participants in the MOTHER study (H. E. Jones et al., New England Journal of Medicine, 2010) found no relationship between maternal methadone dose at delivery and any of 9 neonatal outcomes--peak neonatal abstinence syndrome (NAS) score, total amount of morphine needed to treat NAS, duration of neonatal hospital stay, duration of treatment for NAS, estimated gestational age at delivery, Apgar score at 5 min, and neonatal head circumference, length, and weight at birth. These results are consistent with a recent systematic review and meta-analysis (B. J. Cleary et al., Addiction, 2010) and extend findings to outcomes other than NAS. Methodological and design issues that might have adversely impacted the ability of researchers to establish the existence or non-existence of these relationships are considered.

Opioid addiction in pregnancy

The purpose of this review is to discuss the incidence, risks, pregnancy complications, and maintenance options for treatment of opioid addiction in pregnancy.

SUMMARY

Opioid dependence in pregnancy carries clear identifiable maternal and fetal risk. Providing care for patients with dependence is best done in a multidisciplinary care model addressing the particular needs of this population. There are limited data on maternal detoxification, with data still emerging surrounding the safety profile of this practice. Historically, methadone has been the recommended maintenance treatment; however, recent data on buprenorphine identify this as a safe and effective option. The majority of births from women with opioid dependence result in neonatal abstinence syndrome requiring prolonged neonatal hospitalization. Intrapartum pain management should not differ from the general obstetric population. Postpartum pain is magnified in this population, and particular attention should be focused on this issue. Breast-feeding is recommended regardless of maintenance dose, unless other conditions restricting breast-feeding are present. Comprehensive postpartum care and transition of care to addiction specialists are highly recommended.

TARGET AUDIENCE

Obstetricians and gynecologists, family physicians, addiction specialists.

LEARNING OBJECTIVES

After completing this CME activity, physicians should be better able to assess the treatment options available to patients with opioid addiction during pregnancy, compare the risk/safety profiles of methadone and buprenorphine, and evaluate the recommendations and current data surrounding breast-feeding while on opioid maintenance treatment.

Contingent incentives reduce cigarette smoking among pregnant, methadone-maintained women: results of an initial feasibility and efficacy randomized clinical trial

AIMS

This study examined the feasibility and efficacy of behavioral incentives for reducing cigarette smoking among pregnant methadone-maintained patients.

DESIGN

Participants (n = 102) were assigned randomly to: (i) contingent behavioral incentives (CBI: n = 42); (ii) non-contingent behavioral incentives (NCBI: n = 28); or (iii) treatment as usual (TAU: n = 32).

SETTING

Study procedures were implemented at the Center for Addiction and Pregnancy in Baltimore, MD.

PARTICIPANTS

Study participants were pregnant, methadone-maintained women enrolled in substance use disorder treatment.

MEASUREMENTS

Baseline carbon monoxide (CO) levels were calculated for each participant. Subsequently, breath samples were tested three times weekly to measure changes in smoking behavior. CBI participants received incentives for target reductions from baseline: any reduction (week 1); 10% reduction (weeks 2-4), 25% reduction (weeks 5-7), 50% reduction (weeks 8-9), 75% reduction (week 10-11); and abstinence [CO < 4 parts per million (p.p.m.)] (week 12 until delivery). NCBI participants received incentives independent of smoking CO measurement results. TAU participants received no incentives, the standard treatment at the program.

FINDINGS

CBI condition participants submitted significantly lower mean CO values than the NCBI and TAU conditions over the course of the intervention (P < 0.0001). Nearly half (48%) of the CBI participants met the 75% smoking reduction target and one-third (31%) met the abstinence target at week 12. In contrast, none of the NCBI met either the 75% or abstinence targets. Only 2% of the TAU participants met the 75% reduction and none of the TAU participants met the abstinence targets. These smoking behavior reductions did not yield significant differences in birth outcomes.

CONCLUSIONS

Cigarette smoking may be reduced significantly among pregnant, methadone-maintained women through the use of contingent reinforcement for gradual reductions in breath carbon monoxide levels.

Opioid dependency in pregnancy and length of stay for neonatal abstinence syndrome

OBJECTIVE

To examine opioid replacement therapy in pregnancy and effect on neonatal outcomes, including length of hospital stay for neonatal abstinence syndrome.

DESIGN

Retrospective descriptive study.

SETTING

Labor and delivery unit and neonatal intensive care unit (NICU), Eastern Maine Medical Center, Bangor, Maine.

PARTICIPANTS

One hundred fifty-two opioid-dependent pregnant women on methadone maintenance therapy (MMT) (n = 136) or buprenorphine maintenance therapy (BMT) (n = 16) during pregnancy and their neonates. The neonates were born between January 1, 2005 and December 31, 2007.

METHODS

A review of the electronic medical record (EMR) was conducted of all opioid-dependent women who were maintained on MMT or BMT at the time of admission for labor and delivery and their neonates.

RESULTS

Maternal methadone dose and concomitant in-utero exposure to benzodiazepines prolonged the length of hospital stay for neonates. Length of stay was shorter in breastfed neonates than formula-fed neonates or neonates who received formula and breast milk. Neonates with prenatal exposure to MMT spent more days in the hospital (21 vs. 14 days) for treatment of neonatal abstinence syndrome (NAS) than infants with prenatal exposure to BMT.

CONCLUSION

These findings are consistent with previous research on the simultaneous use of methadone and benzodiazepines during pregnancy and provide further direction for the treatment of opioid dependency during pregnancy. Harm reduction strategies for opioid-dependent pregnant women in substance abuse treatment with MMT may one day include guidance on daily treatment doses and recommendations to avoid the concomitant use of benzodiazepines to lessen NAS. Breastfeeding should be recommended to shorten length of stay. Understanding perinatal and neonatal outcomes of pregnant women on methadone or buprenorphine will help to identify optimal treatment for opioid dependency in pregnancy.

Pain relief after cesarean section: Oral methadone vs. intramuscular pethidine

BACKGROUND

Appropriate pain management is needed during the post-partum hospitalization period for preventing cesarean section (CS) related complications. Protocols of post-partum pain management should be planned based on the facilities of each center or region. The aim of current study was to compare the analgesic efficacy of oral methadone and intra muscular (IM) pethidine which the latter was routinely used in our center in post cesarean pain treatment.

MATERIALS AND METHODS

In this prospective double-blind clinical trial, women who were candidate for cesarean section were selected and randomized into two groups. All patients routinely received a single IM pethidine dose (50 mg) after CS in the recovery room. One group of patients received 0.7 mg/kg pethidine every 6 hour IM, and another group received 0.07 mg/kg oral methadone every 6 hour. Severity of pain assessed using visual analogue scale (VAS) score in 6, 12, 18 and 24 hour after surgery.

RESULTS

Pain severity in methadone group at 6, 12, 18 and 24 hour post operation were 6.4 ± 0.9, 3.4 ± 0.8, 1.9 ± 1.1, 0.5 ± 0.5 (p < 0.05) and for patients in pethidine group were 6.6 ± 0.8, 3.4 ± 0.9, 2.1 ± 1.0 and 0.5 ± 0.5 (p < 0.05), respectively (Mean ± SD). Between groups differences in each follow up time were not statistically significant. There was no difference between groups in terms of complications and supplementary analgesic use.

CONCLUSION

Considering the similar analgesic effects of methadone and pethidine, satisfaction of patients and nursing system with methadone use and the cost benefit of methadone, it can be recommended to use methadone for post operative pain relieving.

Estimated infant exposure to enantiomer-specific methadone levels in breastmilk

BACKGROUND AND OBJECTIVES

Breastfeeding, a public health priority, improves outcomes for infants. Methadone is dispensed as a racemic mixture; R-methadone is the active enantiomer. Pharmacologic data for R-methadone in breastmilk could improve risk-benefit decision-making for treatment of lactating women. This study estimated infant exposure to R- and S-methadone via breastmilk by theoretic infant dose (TID) and relative infant dose (RID) and reported the milk-to-maternal plasma (M/P) ratio.

METHODS

Women treated with methadone doses of 40-200 mg/day (mean, 102 mg/day) provided concomitantly collected plasma and breastmilk samples 1-6 days after delivery. Most (16 of 20) samples were taken at the time of peak maternal plasma levels; thus infant exposure estimates are for maximum possible exposure. Concentrations of R- and S-methadone were measured in maternal plasma and breastmilk; M/P ratio, TID, and RID were calculated for each enantiomer and total methadone.

RESULTS

The 20 participants were 18-38 years old and publicly insured; a quarter did not complete high school, and only one was not white. R-Methadone concentration was 1.3-3.0 times that of S-methadone in all breastmilk samples. The mean (SD) R-, S-, and total methadone M/P ratios were 0.52 (0.28), 0.28 (0.15), and 0.40 (0.21), respectively. Mean (range) R-, S-, and total methadone TID were 0.02 mg/kg/day (0.004-0.099), 0.013 mg/kg/day (0.002-0.071), and 0.033 mg/kg/day (0.006-0.170), respectively. Mean (range) RID of R-, S-, and total methadone were 2.7% (0.7-10.1%), 1.6% (0.3-7.2%), and 2.1% (0.52-8.8%), respectively.

CONCLUSIONS

R-Methadone is found in higher concentrations than S-methadone in breastmilk. Even at high methadone doses, breastmilk methadone concentrations were relatively low and support American Academy of Pediatrics recommendations that dose should not be a factor in determining whether women on methadone breastfeed.

The impact of infant feeding method on neonatal abstinence scores of methadone-exposed infants

PURPOSE

To determine whether neonatal abstinence scores of infants exposed to methadone in utero differed by infant feeding method.

DESIGN

A retrospective chart review.

SUBJECTS

Twenty-eight term infants that were exposed to methadone in utero and exhibited symptoms of neonatal abstinence syndrome (NAS) prior to hospital discharge were included into the study. The sample was further divided by self-selected infant feeding method including (1) predominately breastfed (n = 8), combination fed (n = 11) or predominately formula fed (n = 9).

METHODS

Data were extracted by two independent researchers from both the mother's and infant's chart. This included variables such as NAS scores, NAS treatment, infant feeding method and baseline demographic information.

MAIN OUTCOME MEASURES

NAS scores were assessed by Registered Nurses according to hospital protocol using a Modified Finnegan Scoring Tool.

PRINCIPAL RESULTS

A non-parametric Kruskal-Wallis one way analysis of variance based on ranks revealed statistically significant differences in the number of NAS scores recorded (P = 0.001), magnitude (P < 0.0001) and area score (P = 0.04) by infant feeding method. In particular, infants who were predominantly breastfed had significantly fewer NAS scores done and lower mean scores suggesting decreased severity and duration of NAS symptoms when compared to infants who were combination fed or predominately formula fed.

CONCLUSION

Breastfeeding may offer enhanced benefits for infants who have been exposed to methadone in utero. As such, in the absence of contraindications, mothers in methadone maintenance programs should be encouraged and supported to breastfeed their infants.

Bioanalytical procedures and recent developments in the determination of opiates/opioids in human biological samples

The use and abuse of illegal drugs affects all modern societies, and therefore the assessment of drug exposure is an important task that needs to be accomplished. For this reason, the reliable determination of these drugs and their metabolites in biological specimens is an issue of utmost relevance for both clinical and forensic toxicology laboratories in their fields of expertise, including in utero drug exposure, driving under the influence of drugs and drug use in workplace scenarios. Most of the confirmatory analyses for abused drugs in biological samples are performed by gas chromatographic-mass spectrometric methods, but use of the more recent and sensitive liquid chromatography-(tandem) mass spectrometry technology is increasing dramatically. This article reviews recently published articles that describe procedures for the detection of opiates in the most commonly used human biological matrices, blood and urine, and also in unconventional ones, e.g. oral fluid, hair, and meconium. Special attention will be paid to sample preparation and chromatographic analysis.

Maternal methadone dose, placental methadone concentrations, and neonatal outcomes

BACKGROUND

Few investigations have used placenta as an alternative matrix to detect in utero drug exposure, despite its availability at the time of birth and the large amount of sample. Methadone-maintained opioid-dependent pregnant women provide a unique opportunity to examine the placental disposition of methadone and metabolite [2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP)], to explore their correlations with maternal methadone dose and neonatal outcomes, and to test the ability to detect in utero exposure to illicit drugs.

METHODS

We calculated the correlations of placental methadone and EDDP concentrations and their correlations with maternal methadone doses and neonatal outcomes. Cocaine- and opiate-positive placenta results were compared with the results for meconium samples and for urine samples collected throughout gestation.

RESULTS

Positive correlations were found between placental methadone and EDDP concentrations (r=0.685), and between methadone concentration and methadone dose at delivery (r=0.542), mean daily dose (r=0.554), mean third-trimester dose (r=0.591), and cumulative daily dose (r=0.639). The EDDP/methadone concentration ratio was negatively correlated with cumulative daily dose (r=-0.541) and positively correlated with peak neonatal abstinence syndrome (NAS) score (r=0.513). Placental EDDP concentration was negatively correlated with newborn head circumference (r=-0.579). Cocaine and opiate use was detected in far fewer placenta samples than in thrice-weekly urine and meconium samples, a result suggesting a short detection window for placenta.

CONCLUSIONS

Quantitative methadone and EDDP measurement may predict NAS severity. The placenta reflects in utero drug exposure for a shorter time than meconium but may be useful when meconium is unavailable or if documentation of recent exposure is needed.

Prenatal methadone exposure, meconium biomarker concentrations and neonatal abstinence syndrome

AIMS

Methadone is standard pharmacotherapy for opioid-dependent pregnant women, yet the relationship between maternal methadone dose and neonatal abstinence syndrome (NAS) severity is still unclear. This research evaluated whether quantification of fetal methadone and drug exposure via meconium would reflect maternal dose and predict neonatal outcomes.

DESIGN

Prospective clinical study.

SETTING

An urban drug treatment facility treating pregnant and post-partum women and their children.

PARTICIPANTS

Forty-nine opioid-dependent pregnant women received 30-110 mg methadone daily.

MEASUREMENTS

Maternal methadone dose, infant birth parameters and NAS assessments were extracted from medical records. Thrice-weekly urine specimens were screened for opioids and cocaine. Newborn meconium specimens were quantified for methadone, opioid, cocaine and tobacco biomarkers.

FINDINGS

There was no relationship between meconium methadone concentrations, presence of opioids, cocaine and/or tobacco in meconium, maternal methadone dose or NAS severity. Opioid and cocaine were also found in 36.7 and 38.8 of meconium specimens, respectively, and were associated with positive urine specimens in the third trimester. The presence of opioids other than methadone in meconium correlated with increased rates of preterm birth, longer infant hospital stays and decreased maternal time in drug treatment.

CONCLUSIONS

Methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) concentrations in meconium did not predict infant birth parameters or NAS severity. Prospective urine testing defined meconium drug detection windows for opiates and cocaine as 3 months, rather than the currently accepted 6 months. The presence of opioids in meconium could be used as a biomarker for infants at elevated risk in the newborn period.

Breastfeeding rates among mothers of infants with neonatal abstinence syndrome

BACKGROUND

Woman who struggle with drug addiction during pregnancy are perhaps the most vulnerable of new mothers. The opioid substitution medications methadone and buprenorphine are both compatible with breastfeeding. The objective of this study is to determine breastfeeding rates among opioid-dependent women giving birth in a Baby-Friendly Hospital.

METHODS

We performed a retrospective chart review of all infants born at Boston Medical Center (Boston, MA) between July 2003 and January 2009 with a diagnosis of neonatal abstinence syndrome. Feeding information was obtained, as well as baseline medical information about the mother-infant pairs. Breastfeeding eligibility was determined by a negative urine toxicology screen on admission, no illicit drug use in the third trimester, and a negative human immunodeficiency virus status.

RESULTS

Two hundred seventy-six mother-infant pairs were identified. Forty percent of the mothers carried one or more psychiatric diagnoses; 24% were taking two or more psychiatric medications. Sixty-eight percent of the mothers were eligible to breastfeed; of those, 24% breastfed to some extent during their infant's hospitalization. Sixty-percent of those who initiated stopped breastfeeding after an average of 5.88 days (SD 6.51).

CONCLUSIONS

Breastfeeding rates among opioid-dependent women were low, with three-quarters of those eligible electing not to breastfeed. Of the minority of women who did choose to breastfeed, more than half stopped within 1 week.

ABM clinical protocol #21: Guidelines for breastfeeding and the drug-dependent woman

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Maternal methadone dosing schedule and fetal neurobehaviour

OBJECTIVE

Daily methadone maintenance is the standard of care for opiate dependency during pregnancy. Previous research has indicated that single-dose maternal methadone administration significantly suppresses fetal neurobehaviours. The purpose of this study was to determine if split-dosing would have less impact on fetal neurobehaviour than single-dose administration.

METHODS

Forty methadone-maintained women were evaluated at peak and trough maternal methadone levels on single- and split-dosing schedules. Monitoring sessions occurred at 36- and 37-weeks gestation in a counterbalanced study design. Fetal measures included heart rate, variability, accelerations, motor activity and fetal movement-heart rate coupling (FM-FHR). Maternal measures included heart period, variability, skin conductance, respiration and vagal tone. Repeated measure analysis of variance was used to evaluate within-subject changes between split- and single-dosing regimens.

RESULTS

All fetal neurobehavioural parameters were suppressed by maternal methadone administration, regardless of dosing regimen. Fetal parameters at peak were significantly lower during single versus split methadone administration. FM-FHR coupling was less suppressed from trough to peak during split-dosing versus single-dosing. Maternal physiologic parameters were generally unaffected by dosing condition.

CONCLUSION

Split-dosed fetuses displayed less neurobehavioural suppression from trough to peak maternal methadone levels as compared with single-dosed fetuses. Split-dosing may be beneficial for methadone-maintained pregnant women.

Methadone maintenance and long-term lactation

Breastfeeding among methadone-maintained women is frequently challenged because of unclear guidelines regarding this practice. Previous research has confirmed that concentrations of methadone in breastmilk in the neonatal period are low. Currently unknown are the concentrations of methadone in breastmilk among women who breastfeed for longer periods of time. The purpose of this research is to examine concentrations of methadone in the plasma and breastmilk of women who breastfeed their infants beyond the neonatal period. Four methadone-maintained women provided blood and breastmilk samples up to 6 months postpartum. The concentrations of methadone in blood and breastmilk were low, contributing to the recommendation of breastfeeding for some methadone-maintained women.

Methadone maintenance and breastfeeding in the neonatal period

OBJECTIVE

In a sample of methadone-maintained breastfeeding women and a matched group of formula-feeding women, this study evaluated concentrations of methadone in breast milk among breastfeeding women and concentrations of methadone in maternal and infant plasma in both groups.

METHODS

Eight methadone-maintained (dose: 50-105 mg/day), lactating women provided blood and breast milk specimens on days 1, 2, 3, 4, 14, and 30 after delivery, at the times of trough and peak maternal methadone levels. Paired specimens of foremilk and hindmilk were obtained at each sampling time. Eight matched formula-feeding subjects provided blood samples on the same days. Infant blood samples for both groups were obtained on day 14. Urine toxicological screening between 36 weeks of gestation and 30 days after the birth confirmed that subjects were not using illicit substances in the perinatal period.

RESULTS

Concentrations of methadone in breast milk were low (range: 21.0-462.0 ng/mL) and not related to maternal dose. There was a significant increase in methadone concentrations in breast milk over time for all 4 sampling times. Concentrations of methadone in maternal plasma were not different between groups and were unrelated to maternal dose. Concentrations of methadone in infant plasma were low (range: 2.2-8.1 ng/mL) in all samples. Infants in both groups underwent neurobehavioral assessments on days 3, 14, and 30; there were no significant effects of breastfeeding on neurobehavioral outcomes. Fewer infants in the breastfed group required pharmacotherapy for neonatal abstinence syndrome, but this was not a statistically significant finding.

CONCLUSION

Results contribute to the recommendation of breastfeeding for methadone-maintained women.

Validation of a LC–APCI-MS/MS method for quantification of methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenylpyraline (EMDP) in infant plasma following protein precipitation

A validated, quantitative LC-APCI-MS/MS method for methadone, EDDP and EMDP in 200-microL plasma is presented. Specimen preparation was limited to protein precipitation and centrifugation. Chromatographic separation was achieved on a Synergi Hydro-RP 80A (50 mm x 2.0 m, 4 microm) column with gradient elution. The assay was linear from 1 to 500 ng/mL, with intra- and inter-assay accuracy >or=87.5% and intra- and inter-assay precision <13.4% R.S.D. and recovery >or=87.5% for all analytes at 40 ng/mL. This analytical method is suitable for the accurate and precise determination of methadone and metabolites in human plasma specimens.