Methadone and buprenorphine toxicity in children

The clinico-epidemiological, diagnostic, and therapeutic aspects of methadone poisoning: a registry-based clinical study

Objectives

Methadone is a long-acting synthetic agonist of opioid receptors, which is used as an analgesic and as an alternative treatment in opioid-dependent patients. Clinical manifestations of methadone poisoning include miotic pupils, low levels of consciousness (LOC), respiratory depression or apnea, and coma and death. Considering the high consumption of methadone in society and the prevalent instances of overdose and poisoning, whether accidental or intentional, the authors decided to investigate the clinico-epidemiological, diagnostic, and therapeutic characteristics of methadone poisoning in the Mazandaran province, northern Iran, from 2020 to 2022.

Methods

This study was a retrospective and descriptive cross-sectional registry-based study, wherein data was collected from the Mazandaran Registry Center of Opioids Poisoning (MRCOP), on patients with methadone poisoning. Data based on various parameters such as individual characteristics, ingestion motivation, and clinical outcomes were collected in a checklist.

Results

Of the 385 patients, who entered the study, 264 were men and 121 were women. The mean age of the patients was 29.02 years. Two hundred forty-four patients had intentionally consumed methadone. The most common symptoms observed among individuals with methadone poisoning were decreased arterial blood oxygen (225 patients) and decreased LOC (173 patients). The length of hospitalization for most patients was less than 1 week. Except for seven of them who died, most of them were discharged in good general condition.

Conclusion

The study identified sex, age, marital and employment status, and suicidal intent as the most significant factors influencing methadone poisoning, which should be considered in the design and implementation of public education and prevention programs.

Buprenorphine and its formulations: a comprehensive review

Buprenorphine, a novel long-acting analgesic, was developed with the intention of two purposes: analgesia and opioid use disorder. Regarding its pharmacodynamics, it is a partial agonist at mu receptors, an inverse agonist at kappa receptors, and an antagonist at delta receptors. For the purpose of analgesia, three formulations of buprenorphine were developed: IV/IM injectable formulation (Buprenex®), transdermal patch formulation (Butrans®), and buccal film formulation (Belbuca®). Related to opioid dependence, the formulations developed were subcutaneous extended release (Sublocade®), subdermal implant (Probuphine®), and sublingual tablets (Subutex®). Lastly, in order to avoid misuse of buprenorphine for opioid dependence, two combination formulations paired with naloxone were developed: film formulation (Suboxone®) and tablet formulation (Zubsolv®). In this review, we present details of each formulation along with their similarities and differences between each other and clinical considerations.

Sex specific effects of buprenorphine on behavior, astrocytic opioid receptor expression and neuroinflammation after pediatric traumatic brain injury in mice

Children who suffered traumatic brain injury (TBI) often experience acute and chronic pain, which is linked to a poor quality of life. Buprenorphine (BPN) is commonly used to treat moderate to severe persistent pain in children, however, the efficacy and safety profile of BPN in the pediatric population is still inconclusive. This study investigated the sex-specific effects of BPN on body weight, motor coordination and strength, expression of opioid receptors in the white matter astrocytes, and neuroinflammation in a mouse impact acceleration model of pediatric TBI. Male and female littermates were randomized on postnatal day 20-21(P20-21) into Sham, TBI + saline and TBI + BPN groups. Mice in the TBI + saline and TBI + BPN groups underwent TBI, while the Sham group underwent anesthesia without injury. BPN (0.075 mg/kg) was administered to the TBI + BPN mice at 30 min after injury, and then every 6-12 h for 2 days. Mice in the TBI + saline group received the same amount of saline injections. The impact of BPN on body weight, motor function, opioid receptor expression, and neuroinflammation was evaluated at 1-day (d), 3-d and 7-d post-injury. We found that 1) TBI induced significant weight loss in both males and females. BPN treatment improved weight loss at 3-d post-injury in females. 2) TBI significantly impaired motor coordination and strength. BPN improved motor coordination and strength in both males and females at 1-d and 3-d post-injury. 3) TBI significantly decreased exploration activity at 1-d post-injury in males, and at 7-d post-injury in females, while BPN improved the exploration activity in females. 4) TBI significantly increased mRNA expression of mu-opioid receptors (MOR) at 7-d post-injury in males, but decreased mRNA expression of MOR at 1-d post-injury in females. BPN normalized MOR mRNA expression at 1-d post-injury in females. 5) MOR expression in astrocytes at corpus callosum significantly increased at 7-d post-injury in male TBI group, but significantly decreased at 1-d post-injury in female TBI group. BPN normalized MOR expression in both males and females. 6) TBI significantly increased the mRNA expression of TNF-α, IL-1β, IL-6 and iNOS. BPN decreased mRNA expression of iNOS, and increased mRNA expression of TGF-β1. In conclusion, this study elucidates the sex specific effects of BPN during the acute phase after pediatric TBI, which provides the rationale to assess potential effects of BPN on chronic pathological progressions after pediatric TBI in both males and females.

Unintentional Opioid Ingestions Presenting to a Pediatric Emergency Department

OBJECTIVES

The purpose of this study was to describe unintentional opioid exposures in young children, including demographics, medical interventions, and clinical outcomes.

METHODS

This was a retrospective, cross-sectional study of children 0 to 6 years of age with possible opioid exposure over a 3-year period (July 2010 to June 2013). Data collected included sex, age, specific drug, whether they were referred to the emergency department (ED) by the Regional Poison Control Center, presence of symptoms, therapeutic interventions, ED disposition, and clinical outcomes for admitted patients.

RESULTS

Median age of patients included in the study was 2 years, and 64% of these children were male. The most common drug of exposure was buprenorphine/naloxone. Of the 429 charts screened, 140 patients were reported to be symptomatic and referred to the ED, of which 113 patients actually presented to the ED. An additional 122 patients presented to the ED without Regional Poison Control Center referral. Of the total 235 patients presenting to ED, 76 (32%) received a therapeutic intervention. Of 231 total opioid exposures, 31 exposures were administered naloxone. Three children underwent endotracheal intubation. Sixty-five patients were hospitalized, with a median length of stay of 1 day. Although there were no fatalities, 1 child suffered severe morbidity (anoxic brain injury).

CONCLUSIONS

While opioid exposures in young children are a common and potentially life-threatening problem, most children remain asymptomatic. The majority of patients are able to be discharged from the ED after observation, and of those who are admitted, most have favorable outcomes and brief hospital stays. A small number of these patients require considerable medical interventions.

An examination of fatal child poisonings in the United States using the National Violent Death Reporting System (NVDRS), 2012-2017

BACKGROUND

Fatal drug overdoses are predominantly attributed to opioids. Women of childbearing age are among those at greatest risk, underscoring the need to understand the overlapping risk of fatal poisoning in children.

METHODS

A retrospective analysis of fatal poisonings among decedents aged 0-9 years captured in the National Violent Death Reporting System (NVDRS) from 2012 to 2017 was employed. Poisonings were identified using International Classification of Diseases, Tenth Revision (ICD-10) codes for poisonings (T36-T50, Y10-Y19), toxic effects of substances (T51-T65), and assault (X85-X90). The frequency and types of drugs involved in poisonings were derived from toxicological analysis. Logistic regression was used to model the odds of fatal poisoning by decedent and perpetrator characteristics. Qualitative content analysis was used to contextualize the patterns of fatal poisonings.

FINDINGS

1850 violent deaths were identified; 7% (n = 122) were poisoning-related, and 50% of these were attributed to opioids. Next, benzodiazepines (8%), amphetamines (7%), and antidepressants (5%) were most prevalent. Among poisoning-related deaths, 25% involved homicide-suicide. No differences in deaths were observed according to child race/ethnicity, and the risk of fatal poisoning decreased 6% with each year of child age. Following qualitative analysis, three unique categories of fatal poisoning emerged: "intentional administration without documented benign intent", "intentional administration with benign intent", and "unclear administration".

CONCLUSION

The high proportion of fatal poisonings in children attributed to opioids in this study suggests a need for universal dissemination and training of naloxone in households comprised of children living with parents experiencing, or in recovery for substance misuse. Findings also indicate a needed emphasis on safe storage practices and education to parents about the risk of prescription drug toxicity in children.

Buprenorphine abuse and health risks in Iran: A systematic review

INTRODUCTION

Buprenorphine maintenance treatment (BMT) is widely used in Iran, and its use is growing continuously. We reviewed studies on buprenorphine use, non-prescribed use, use disorder and treatment-seeking for it, buprenorphine-associated poisoning, and mortality in Iran in the current systematic review.

METHODS

An Iranian database (Scientific Information Database; SID) and three International electronic databases (PubMed, Scopus, and Web of Science) were searched for publications up to August 2020 for the relevant data. Opportunistic methods (Contact with experts and backward citation tracking) were also used for this purpose. Identified records were screened for eligibility criteria, and data of included studies were extracted. For context, the trend of BMT in the country was also examined.

RESULTS

Ten studies were found on the prevalence of non-prescribed buprenorphine use, seven were on the regular use and use disorder, and two studies on buprenorphine poisoning. The last 12-month prevalence of non-prescribed use was lower than 0.5 % in the general population, university, and high school students. The indicator was 2.5 % among persons who use drugs in a 2018 national study. The proportion of buprenorphine poisoning was 4.9 % among all illicit substance poisoning cases admitted to a hospital. The proportion of buprenorphine poisoning cases among all acute pediatric drug poisoning cases increased from 1.2 % to 2.5 % in a 3-year study.

CONCLUSION

Despite the expansion of BMT in Iran in the last decade, the adverse health consequences associated with buprenorphine are infrequent, when compared to other opioids used in Iran, suggesting the safety of BMT for future expansion.

A study of the effectiveness of naltrexone in preventing recurrence of methadone poisoning in opioid-naive children

BACKGROUND

The prevalence of poisoning from methadone and prescription opioids is increasing in pediatric populations. Naloxone is the main antidote for treatment. Long-acting opioid toxicity may need close observation in the intensive care unit (ICU). In our previous study, naltrexone prevented re-narcotization in methadone-poisoned adults. Here, we aim to share our experience with the use of oral naltrexone for preventing recurrence of toxicity in opioid-naïve children.

METHODS

In a single-center, retrospective case series, children (age ≤12 years) admitted to a poison center in Tehran (Iran) between March 2014-March 2016 were included if they presented with methadone poisoning and received naltrexone treatment in hospital. Naltrexone (1 mg/kg) was administrated orally after initial administration of 0.1 mg/kg naloxone intravenously. Children were monitored for level of consciousness, cyanosis, respiratory rate, VBG results, and O2 saturation for ≥48 h during their hospitalization.

RESULTS

Eighty patients with methadone poisoning were enrolled, with median age of three years (range: 0.2-12.0). None involved polysubstance poisoning. Following naltrexone treatment, none experienced recurrent opioid toxicity during hospitalization, and hospital records indicated no readmission within 72-h post-discharge.

CONCLUSION

Oral naltrexone could be a potential substitute for continuous naloxone infusion in methadone-poisoned children and reduce the need for ICU care.

Unintentional buprenorphine and methadone poisoning in children: a matched observational study

OBJECTIVE

To compare accidental pediatric poisoning from methadone vs. buprenorphine in terms of clinical indicators and in-hospital morbidity.

METHODS

A matched observational study conducted on children aged ≤12 years admitted to our center between March 2018 and March 2019 with acute poisoning from methadone or buprenorphine. Data were extracted from the electronic patient files of the pediatric methadone poisoning cases, and buprenorphine poisoning cases were followed from ED, during the study period. Cases were compared regarding rates of bradypnea/apnea (primary outcome), the need for antidote therapy and intubation, duration of hospital stay, miosis, loss of consciousness, blood gas analyses, and mortality (secondary outcomes).

RESULTS

A total of 90 methadone- and 30 buprenorphine-poisoned children were evaluated. Methadone cases had significantly higher rates of apnea (20/90 methadone vs. 0/30 buprenorphine; OR = 17.7, 95% CI 1.1, 302.8; p = 0.047), but there was no group difference in bradypnea (39/90 methadone vs. 10/30 buprenorphine; p = ns). 28 (31%) methadone and 3 buprenorphine (10%) cases had been referred to as fully awake (p = 0.013). Methadone cases required higher median naloxone doses for initial bolus (0.4 vs. 0.02 mg; p = 0.014) and maintenance infusion (14.4 vs. 2.4 mg; p < 0.001). 20 apnea cases (all from the methadone group) had miotic pupils, and miotic pupils were seen in 44 (90%) cases with bradypnea (OR = 3.2, 95% CI 1.1, 9.3; p = 0.026). Intubation was needed in only 5 methadone cases (5.5%; p = ns). All patients survived.

CONCLUSION

Compared to children poisoned with methadone, buprenorphine cases had higher rates of loss of consciousness on admission but subsequently experienced fewer complications during hospital treatment, which is likely due to the buprenorphine partial antagonist effect. Our findings suggest that methadone exposure is more toxic than buprenorphine in pediatric populations.

Veterinary-Prescribed Buprenorphine Ingestion in a 2-Year-Old Girl

INTRODUCTION

Ingestion of buprenorphine by young children is on the rise and can lead to life-threatening consequences and death. Exposure most often occurs when a child acquires the medication intended for adult use. However, buprenorphine is also prescribed by veterinarians and may be sent home, typically in non-child-resistant packaging, to be administered to the family pet.

CASE

A previously healthy 2-year-old girl weighing 11.36 kg was found with a 1-mL syringe containing 0.6 mg/mL of buprenorphine in her mouth. The syringe had been in a plastic bag provided to the family by their veterinarian for the family dog. She was hospitalized for 24 hours but remained asymptomatic and was discharged healthy. This type of exposure to buprenorphine has not previously been described in the literature.

CONCLUSIONS

Having this unsecured medication in the home increases the potential risk of exposure for young children and associated health consequences. Pediatricians should be aware of the potential dangers that veterinary pharmaceuticals can pose and educate parents about proper storage of medications. In addition, veterinarians should take extra precautions when dispensing these medications to pet owners with children.

Epidemiology of pediatric buprenorphine and methadone exposures reported to the poison centers

BACKGROUND

Buprenorphine prescriptions have increased dramatically within the United States, whereas methadone continues to be used widely. We investigated the trends and characteristics of buprenorphine and methadone exposures in the pediatric population.

METHODS

We identified pediatric exposures to buprenorphine and methadone using the National Poison Data System from 2013 to 2016. We descriptively assessed characteristics of the exposures. Trends in exposures were evaluated using generalized linear mixed models.

RESULTS

Pediatric buprenorphine exposures increased from 2013 (1097) to 2016 (1226) while methadone calls decreased (486 to 396). After adjusting for the random effects of the geographical region, the mean number of pediatric buprenorphine exposures (per 100,000 pediatric population) increased from 1.3 to 1.5 (P = .05). Conversely, the mean number of methadone exposures decreased from 0.6 to 0.4 (P = .03). Children aged ≤3 years constituted the highest percentage of both exposures. Unintentional exposures accounted for most of the buprenorphine (86.9%) and methadone (62.4%) exposures. Major clinical effects were demonstrated in 2.3% of buprenorphine exposures and were more frequent with methadone (13%). West Virginia and Maryland demonstrated the highest incidence of buprenorphine and methadone exposures, respectively.

CONCLUSIONS

Pediatric buprenorphine exposures increased but demonstrated less severe effects compared to methadone exposures, which decreased during the study period.

Long-time effects of prenatal morphine, tramadol, methadone, and buprenorphine exposure on seizure and anxiety in immature rats

Purpose: This study aimed to investigate seizures and anxiety-like behaviors in immature rats prenatally exposed to opiate drugs.Materials and methods: Pregnant rats were randomly divided into five groups: saline, morphine, tramadol, methadone, and buprenorphine. Administrations were performed intraperitoneally once a day for the last seven days of pregnancy. Neonatal rats were subdivided into ten groups, split according to sex. Anxiety-like behavior was tested on postnatal day (PD) 19. On PD 20, seizure was induced by PTZ injection.Results: Morphine in male rats had an increased time to onset (p < 0.005), whereas there was a decreased number of tonic-clonic seizures in females (p < 0.05). Tramadol had an increased duration of tonic-clonic seizures compared to morphine and methadone in males (p < 0.005). Moreover, tramadol decreased open arm time and locomotor activity in males more than in females (p < 0.05). Methadone decreased open arm time in males (p < 0.05). Furthermore, buprenorphine and tramadol decreased open arm entrance in male rats (p < 0.05).Conclusions: It was demonstrated that prenatal tramadol significantly increases both the duration of seizures and anxiety-like behaviors in immature male rats, whereas morphine decreases both of them. The effects of tramadol on seizure and anxiety-like behavior may be due to the comorbid occurrence of the symptoms of these two disorders.

Buprenorphine Overdose in Young Children: An Underappreciated Risk

The escalation of the opioid crisis has led to an increase in the treatment of opioid use disorder. In particular, recent legislation has allowed for office-based treatment with buprenorphine, a partial µ-opioid agonist that is believed to be safer than methadone due to a ceiling effect on respiratory depression in adults. An increasing number of children are being exposed to buprenorphine as more adults in US households receive take-home prescriptions. The ceiling effect seen in adults does not seem to apply to young children, and intoxication with severe symptoms including fatalities can occur. This article outlines the pharmacology of buprenorphine and reviews the current literature on overdose in children. We conclude with practical recommendations for limiting potential exposure and damage to children from accidental buprenorphine overdose.

Novel Formulations of Buprenorphine for Treatment of Opioid Use Disorder

Opioid use disorder (OUD) is epidemic in the United States. In addition to medical, economic, and social impairments, risk of overdose fatality is high. In 2017, there were 14,958 deaths from natural or semisynthetic opioids, 15,958 from heroin, and 29,406 from synthetic opioids, such as fentanyl. Psychosocial interventions do not add substantial efficacy to medical OUD treatments, and thus making evidence-based OUD treatments more accessible is urgent. However, considerable diversion of oral and transmucosal opioid maintenance medications has been documented. Delivery systems that reduce risks of nonadherence through diversion or altered self-administration may increase buprenorphine's effectiveness for clinical stabilization via increased treatment exposure. The article presents findings from multisite efficacy studies of two subcutaneous depot buprenorphine formulations and a long-acting implant. Novel delivery systems show promise in providing improved outcomes through intermediate- and long-acting exposure to medication while reducing the risk of medication nonadherence, diversion, and accidental exposure.

Treating Chronic Pain: An Overview of Clinical Studies Centered on the Buprenorphine Option

The buprenorphine receptor binding profile is unique in that it binds to all three major opioid receptors (mu, kappa, delta), and also binds to the orphan-like receptor, the receptor for orphanin FQ/nociceptin, with lower affinity. Within the mu receptor group, buprenorphine analgesia in rodents is dependent on the recently discovered arylepoxamide receptor target in brain, which involves a truncated 6-transmembrane mu receptor gene protein, distinguishing itself from morphine and most other mu opioids. Although originally designed as an analgesic, buprenorphine has mainly been used for opioid maintenance therapy and only now is increasingly recognized as an effective analgesic with an improved therapeutic index relative to certain potent opioids. Albeit a second-, third-, or fourth-line analgesic, buprenorphine is a reasonable choice in certain clinical situations. Transdermal patches and buccal film formulations are now commercially available as analgesics. This review discusses buprenorphine pharmacodynamics and pharmacokinetics, use in certain populations, and provides a synopsis of systematic reviews and randomized analgesic trials. We briefly discuss postoperative management in patients receiving buprenorphine maintenance therapy, opioid equivalence to buprenorphine, rotations to buprenorphine from other opioids, and clinical relevance of buprenorphine-related QTc interval changes.

Methadone for Analgesia in Children with Life-Limiting Illness: Experience from a Tertiary Children's Health Service

Methadone has the potential to assist in the management of pain in children with life-limiting illness, but its use is limited by its complex pharmacokinetic profile and limited research on its use in children. This is a retrospective review of the use of methadone as an analgesic in 16 children with life-limiting illness. Efficacy, dosing and side effect profile were analysed. Fifteen (94%) patients had improvements in their analgesia with minimal observed adverse effects. Patients were either rapidly converted from a prior opioid in one change or received methadone as an adjunct medication. Conversions were calculated using ratios frequently in the range of 10:1 to 20:1 from the oral morphine equivalent total daily dose (MEDD). Adjunct initial dosing was a low dose trial, often beginning with 1 mg at night. Only two patients required a dose adjustment due to side effects attributed to methadone. This was despite the cohort having significant underlying illnesses, extensive concurrent medications, and high methadone dosing where needed. Analysis of dosing and ratios indicates that an individualised approach is required. Based on this and on the infrequency of methadone use in this population, specialist assistance with dosing is recommended. Further research, including prospective and pharmacokinetic studies, is recommended.

Buprenorphine and pain treatment in pediatric patients: an update

Introduction

The usual management of moderate to severe pain is based on the use of opioids. Buprenorphine (BPN) is an opioid with an analgesic potency 50 times greater than that of morphine. It is widely used in various pain models and has demonstrated efficacy and safety in adult patients; however, there are insufficient clinical trials in pediatric populations.

Purpose

The aim of this study was to perform an updated meta-analysis on the implementation of BPN in the treatment of pain in the pediatric population.

Methods

A bibliographic search was carried out in different biomedical databases to identify scientific papers and clinical trials with evidence of BPN use in children and adolescents.

Results

A total of 89 articles were found, of which 66 were selected. Analysis of these items revealed additional sources, and the final review included a total of 112 publications.

Conclusion

Few studies were found regarding the efficacy and safety of BPN use in children. In recent years, the use of this drug in the pediatric population has become widespread, so it is imperative to perform clinical trials and pharmacological and pharmacovigilance studies, which will allow researchers to develop dosage schemes based on the evidence and minimize the risk of adverse effects.

Unintentional methadone and buprenorphine exposures in children: Developing prevention messages

OBJECTIVES

To develop key messages for methadone and buprenorphine safety education material based on an analysis of calls to the NYC Poison Control Center (NYC PCC) and designed for distribution to caregivers of young children.

METHODS

Retrospective review of all calls for children 5 years of age and younger involving methadone or buprenorphine from January 1, 2000, to June 15, 2014. A data abstraction form was completed for each case to capture patient demographics, exposure and caller sites, caller relation to patient, qualitative information regarding the exposure scenario, the product information, if naloxone was given, and the medical outcome of the case.

RESULTS

A total of 123 cases were identified. The ages of the children ranged from 4 days to 5 years; 55% were boys. All exposures occurred in a home environment. The majority of the calls were made to the NYC PCC by the doctor (74%) or nurse (2%) at a health care facility. Approximately one-fourth of the calls came from the home and were made by the parent (22%) or grandparent (2%). More than one-half of the exposures involved methadone (64%). Naloxone was administered in 28% of cases. Approximately one-fourth of the children did not experience any effect after the reported exposure, one-half (51%) experienced some effect (minor, moderate, or major), and there was 1 death (1%). More than one-half of the children were admitted to the hospital, with 40% admitted to critical care and 13% to noncritical care. Approximately 23% were treated and released from the hospital, and 20% were lost to follow-up or never arrived to the hospital. The remaining 4% were managed on site without a visit to the hospital.

CONCLUSION

Exposures to methadone and buprenorphine are dangerous with some leading to serious health effects. Safe storage and disposal instructions are needed for homes where children may be present.

Advances in the delivery of buprenorphine for opioid dependence

Opioid use disorders (OUDs) have long been a global problem, but the prevalence rates have increased over 20 years to epidemic proportions in the US, with concomitant increases in morbidity and all-cause mortality, but especially opioid overdose. These increases are in part attributable to a several-fold expansion in the prescription of opioid pain medications over the same time period. Opioid detoxification and psychosocial treatments alone have each not yielded sufficient efficacy for OUD, but μ-opioid receptor agonist, partial agonist, and antagonist medications have demonstrated the greatest overall benefit in OUD treatment. Buprenorphine, a μ-opioid receptor partial agonist, has been used successfully on an international basis for several decades in sublingual tablet and film preparations for the treatment of OUD, but the nature of formulation, which is typically self-administered, renders it susceptible to nonadherence, diversion, and accidental exposure. This article reviews the clinical trial data for novel buprenorphine delivery systems in the form of subcutaneous depot injections, transdermal patches, and subdermal implants for the treatment of OUD and discusses both the clinical efficacy of longer-acting formulations through increasing consistent medication exposure and their potential utility in reducing diversion. These new delivery systems also offer new dosing opportunities for buprenorphine and strategies for dosing intervals in the treatment of OUD.

A case report of methadone-associated hypoglycemia in an 11-month-old male

BACKGROUND

Methadone is a synthetic μ-opioid receptor agonist that is used in the management of pain, neonatal abstinence withdrawal syndrome, and opioid dependence. Overdose can cause miosis, respiratory depression, and central nervous system depression. Rarely, hypoglycemia has been reported. We present the case of an 11-month-old male who developed hypoketotic, hyperinsulinemic, hypoglycemia after an acute, unintentional methadone exposure.

CASE DETAILS

The patient was a previously healthy 11-month-old male who presented in respiratory failure. He was intubated and transferred to a large tertiary care center where his physical exam was notable for miosis. His labs were notable for a blood glucose of 17 mg/dL, an elevated insulin level, and suppressed serum beta-hydroxybutyrate. The patient was given a dextrose bolus with improvement in blood glucose. Administration of IV naloxone improved his miosis and mental status. A quantitative methadone level was sent upon arrival and was 123 ng/mL. Testing for ethanol, salicylates, sulfonylureas, and metabolic causes of hypoglycemia was negative. A fasting study showed euglycemia with suppression of insulin and appropriate ketosis. Case discussion: We present the case of an 11-month-old male who developed hypoketotic, hyperinsulinemic, hypoglycemia after an acute, unintentional methadone exposure. Alternative explanations for hypoketotic hypoglycemia were rule out. Methadone-induced hypoglycemia has been reported in cancer patients receiving methadone for pain, but a mechanism has not been identified. Based on this case, we believe that the patient's hypoglycemia was the result of methadone-induced insulin secretion.

CONCLUSIONS

This case proposes that hyperinsulinism is the mechanism responsible for methadone-associated hypoglycemia. Methadone exposure should be included in the differential diagnosis of new onset hypoglycemia.

Methadone prolongs cardiac conduction in young patients with cancer-related pain

OBJECTIVE

Methadone prolongs cardiac conduction, from mild corrected QT (QTc) prolongation to torsades de pointes and ventricular fibrillation, in adults. However, methadone use for pain and its effects on cardiac conduction have not been investigated in pediatric populations.

METHODS

A retrospective review of QTc intervals in patients receiving methadone analgesia was conducted. Medical records from a 4-year period (September 2006 to October 2010) at a pediatric oncology institution were reviewed, and correlations were tested between cardiac conduction and methadone dosage and duration of therapy, electrolyte levels, renal and hepatic dysfunction, and concurrent medications.

RESULTS

Of the 61 patients who received methadone, 37 met our inclusion criteria and underwent 137 electrocardiograms (ECGs). During methadone treatment, the mean QTc was longer than that at baseline (446.5 vs 437.55 ms). The mean methadone dose was 27.0±24.3 mg/d (range, 5-125 mg/d; median, 20 mg/d) or 0.47±0.45 mg/kg per day (range, 0.05-2.25 mg/kg per day; median, 0.37 mg/kg per day), and the mean duration of therapy was 49 days. The authors identified a correlation between automated and manual ECG readings by two cardiologists (Pearson r=0.649; p<0.0001), but the authors found no correlations between methadone dose or duration and concurrent QTc-prolonging medications, sex, age, electrolyte abnormalities, or renal or hepatic dysfunction.

CONCLUSION

At a clinically effective analgesic dose, methadone dosage and duration were not correlated with QTc prolongation, even in the presence of other risk factors, suggesting that methadone use may be safe in pediatric populations. The correlation between automated and manual ECG readings suggests that automated ECG readings are reliable for monitoring cardiac conductivity during the reported methadone-dosage regimens.

Pharmacologic Treatment of Pain

Adolescents and children are frequently affected by chronic pain conditions that can lead to disability and distress. The best approach to evaluation and treatment of these conditions involves use of the biopsychosocial model, which includes use of medication management. Chronic pain conditions are treated pharmacologically with a number of different medication classes via several routes of administration as drug delivery systems have progressed. These include anti-inflammatory drugs, muscle relaxants, antiepileptic medicines, antidepressants, opioids, and local anesthetics. Most are prescribed without regulatory body approval to treat specific pain syndromes as data to support their use are sparse. Medical decision making is guided by experience, empiric evidence, extrapolation from adult studies, and matching medication classes with the theorized mechanism of the pain condition. It is not recommended that nonpain practitioners prescribe opioid medications for treatment of chronic pain conditions, and pain management practitioners should seek to minimize their use. The appropriate and commonly used medications for pain conditions are presented in this narrative review.

The opioid abuse and misuse epidemic: implications for pharmacists in hospitals and health systems

PURPOSE

The current epidemic of prescription opioid abuse and misuse in the United States is discussed, with an emphasis on the pharmacist's role in ensuring safe and effective opioid use.

SUMMARY

U.S. sales of prescription opioids increased fourfold from 1999 to 2010, with an alarming rise in deaths and emergency department visits associated with the use of fentanyl, hydrocodone, oxycodone, and other opioid medications. Signs and symptoms of opioid toxicity may include altered mental status, hypoventilation, decreased bowel motility, central nervous system and respiratory depression, peripheral vasodilation, pulmonary edema, hypotension, bradycardia, and seizures. In patients receiving long-term opioid therapy for chronic pain, urine drug testing is an important tool for monitoring and assessment of therapy; knowledge of opioid metabolic pathways and assay limitations is essential for appropriate use and interpretation of screening and confirmatory tests. In recent years, there has been an increase in federal enforcement actions against pharmacies and prescription drug wholesalers involved in improper opioid distribution, as well as increased reliance on state-level prescription drug monitoring programs to track patterns of opioid use and improper sales. Pharmacies are urged to implement or promote appropriate guidelines on opioid therapy, including the use of pain management agreement plans; policies to ensure adequate oversight of opioid prescribing, dispensing, and waste disposal; and educational initiatives targeting patients as well as hospital and pharmacy staff.

CONCLUSION

Pharmacists in hospitals and health systems can play a key role in recognizing the various forms of opioid toxicity and in preventing inappropriate prescribing and diversion of opioids.

Development of an algorithm to identify serious opioid toxicity in children

BACKGROUND

The use of opioids is increasing in children; therefore, opioid toxicity could be a public health problem in this vulnerable population. However, we are not aware of a published algorithm to identify cases of opioid toxicity in children using administrative databases. We sought to develop an algorithm to identify them. After review of literature and de-identified computer profiles, a broad set of ICD-9 CM codes consistent with serious opioid toxicity was selected. Based on these codes, we identified 195 potential cases of opioid toxicity in children enrolled in Tennessee Medicaid. Medical records were independently reviewed by two physicians; episodes considered equivocal were reviewed by an adjudication committee. Cases were adjudicated as Group 1 (definite/probable), Group 2 (possible), or Group 3 (excluded).

RESULTS

Of the 195 potential cases, 168 (86.2%) had complete records for review and 85 were confirmed cases. The overall positive predictive value (PPV) for all codes was 50.6%. The PPV for codes indicating: unintentional opioid overdose (25/31) was 80.7%; intentional opioid overdose (15/30) was 50.0%, adverse events (33/58) was 56.9%, the presence of signs or symptoms compatible with opioid toxicity (12/47) was 25.5%, and no cases were confirmed in records from the two deaths. Of the confirmed cases, 65.8% were related to therapeutic opioid use.

CONCLUSION

For studies utilizing administrative claims to quantify incidence of opioid toxicity in children, our findings suggest that use of a broad set of screening codes coupled with medical record review is important to increase the completeness of case ascertainment.

A review of buprenorphine diversion and misuse: the current evidence base and experiences from around the world

Outpatient opioid addiction treatment with sublingual buprenorphine pharmacotherapy has rapidly expanded in the United States and abroad, and, with this increase in medication availability, there have been increasing concerns about its diversion, misuse, and related harms. This narrative review defines the behaviors of diversion and misuse, examines how the pharmacology of buprenorphine alone and in combination with naloxone influence its abuse liability, and describes the epidemiological data on buprenorphine diversion and intravenous misuse, risk factors for its intravenous misuse, and the unintended consequences of misuse and diversion. Physician practices to prevent, screen for, and therapeutically respond to these behaviors, which are a form of medication nonadherence, are discussed, and gaps in knowledge are identified. Outpatient opioid addiction treatment with sublingual buprenorphine pharmacotherapy experiences from other countries that have varied health care systems, public policies, and access to addiction treatment are shared to make clear that diversion and misuse occur across the world in various contexts, for many different reasons, and are not limited to buprenorphine. Comparisons are made with other opioids with known abuse liability and medications with no known abuse. The objective was to facilitate understanding of diversion and misuse so that all factors influencing their expression (patient and provider characteristics and public policy) can be appreciated within a framework that also recognizes the benefits of addiction treatment. With this comprehensive perspective, further careful work can help determine how to minimize these behaviors without eroding the current benefits realized through improved addiction treatment access and expansion.

Tapering Long-term Opioid Therapy in Chronic Noncancer Pain: Evidence and Recommendations for Everyday Practice

Increasing concern about the risks and limited evidence supporting the therapeutic benefit of long-term opioid therapy for chronic noncancer pain are leading prescribers to consider discontinuing the use of opioids. In addition to overt addiction or diversion, the presence of adverse effects, diminishing analgesia, reduced function and quality of life, or the absence of progress toward functional goals can justify an attempt at weaning patients from long-term opioid therapy. However, discontinuing opioid therapy is often hindered by patients' psychiatric comorbidities and poor coping skills, as well as the lack of formal guidelines for the prescribers. The aim of this article is to review the existing literature and formulate recommendations for practitioners aiming to discontinue long-term opioid therapy. Specifically, this review aims to answer the following questions: What is an optimal opioid tapering regimen? How can the risks involved in a taper be managed? What are the alternatives to an opioid taper? A PubMed literature search was conducted using the keywords chronic pain combined with opioid withdrawal, taper, wean and detoxification. Six hundred ninety-five documents were identified and screened; 117 were deemed directly relevant and are included. On the base of this literature review, this article proposes evidence-based recommendations and expert-based suggestions for clinical practice. Furthermore, areas of lack of evidence are identified, providing opportunities for further research.

Prior Experience with Non-Prescribed Buprenorphine: Role in Treatment Entry and Retention

Buprenorphine availability continues to expand as an effective treatment for opioid dependence, but increases in availability have also been accompanied by increases in non-prescribed use of the medication. Utilizing data from a randomized clinical trial, this mixed-method study examines associations between use of non-prescribed buprenorphine and subsequent treatment entry and retention. Quantitative analyses (N = 300 African American buprenorphine patients) found that patients with prior use of non-prescribed buprenorphine had significantly higher odds of remaining in treatment through 6 months than patients who were naïve to the medication upon treatment entry. Qualitative data, collected from a subsample of participants (n = 20), identified three thematic explanations for this phenomenon: 1) perceived effectiveness of the medication; 2) cost of obtaining prescription buprenorphine compared to purchasing non-prescribed medication; and 3) convenience of obtaining the medication via daily-dosing or by prescription compared to non-prescribed buprenorphine. These findings suggest a dynamic relationship between non-prescribed buprenorphine use and treatment that indicates potential directions for future research into positive and negative consequences of buprenorphine diversion.

A systematic review of the cardiotoxicity of methadone

Methadone is one of the most popular synthetic opioids in the world with some favorable properties making it useful both in the treatment of moderate to severe pain and for opioid addiction. Increased use of methadone has resulted in an increased prevalence of its toxicity, one aspect of which is cardiotoxicity. In this paper, we review the effects of methadone on the heart as well as cardiac concerns in some special situations such as pregnancy and childhood.

METHODS

We searched for the terms methadone, toxicity, poisoning, cardiotoxicity, heart, dysrhythmia, arrhythmia, QT interval prolongation, torsade de pointes, and Electrocardiogram (ECG) in bibliographical databases including TUMS digital library, PubMed, Scopus, and Google Scholar. This review includes relevant articles published between 2000 and 2013. The main cardiac effects of methadone include prolongation of QT interval and torsade de pointes. Other effects include changes in QT dispersion, pathological U waves, Taku-Tsubo syndrome (stress cardiomyopathy), Brugada-like syndrome, and coronary artery diseases. The aim of this paper is to inform physicians and health care staff about these adverse effects. Effectiveness of methadone in the treatment of pain and addiction should be weighed against these adverse effects and physicians should consider the ways to lessen such undesirable effects. This article presents some recommendations to prevent heart toxicity in methadone users.

Pharmacological treatment of chronic non-cancer pain in pediatric patients

Chronic pain in children and young adults occurs frequently and contributes to early disability as well as personal and familial distress. A biopsychosocial approach to evaluation and treatment is recommended. Within this approach, there is a role for pharmacologic intervention. A variety of medications are used for chronic pain conditions in pediatric patients. Medication classes include anticonvulsants, muscle relaxants, antidepressants, opioids, local anesthetics, and anti-inflammatory drugs. Data is sparse, and most medications are used without condition-specific approval by national regulatory agencies such as the Food and Drug Administration in the US and the European Medicines Agency. In the absence of evidence on which to base practice, optimal drug therapy decisions rest on understanding proposed mechanisms of pain conditions, extrapolation from adult data-when such exists, and empirical and experiential knowledge. Drug delivery systems have evolved, and practitioners have to decide amongst not only medication classes, but also routes of delivery. Opioids are not recommended for use by non-pain specialists for the treatment of pediatric chronic pain, and even then the issues are more complex than can be addressed here. This article reviews the major medications used for pediatric chronic pain conditions.

Buprenorphine-naloxone therapy in pain management

Buprenorphine-naloxone (bup/nal in 4:1 ratio; Suboxone; Reckitt Benckiser Pharmaceuticals Incorporation, Richmond, VA) is approved by the Food and Drug Administration for outpatient office-based addiction treatment. In the past few years, bup/nal has been increasingly prescribed off-label for chronic pain management. The current data suggest that bup/nal may provide pain relief in patients with chronic pain with opioid dependence or addiction. However, the unique pharmacological profile of bup/nal confers it to be a weak analgesic that is unlikely to provide adequate pain relief for patients without opioid dependence or addiction. Possible mechanisms of pain relief by bup/nal therapy in opioid-dependent patients with chronic pain may include reversal of opioid-induced hyperalgesia and improvement in opioid tolerance and addiction. Additional studies are needed to assess the implication of bup/nal therapy in clinical anesthesia and perioperative pain management.

Buprenorphine for opioid dependence: Are there really differences between the formulations?

Buprenorphine and buprenorphine/naloxone sublingual tablets were approved by the FDA in 2002. In 2010, the buprenorphine/naloxone sublingual film was approved to address concerns of diversion, time for tablet dissolution, and unintentional exposure in children with the tablet. This article will compare the buprenorphine sublingual formulations in terms of pharmacokinetics, safety, diversion and misuse, cost, and patient preference. It will explore current data suggesting advantages or disadvantages of the various formulations since conclusive data are minimally available.

Children intoxications: what is abuse and what is not abuse

The curiosity and the natural tendency to explore the environment put young children at an increased risk of poisoning over older children and adults. Poisonings are a significant area of concern from 1 year of age and progressively contribute more to overall rates of morbidity and mortality until children reach adulthood. Particularly, the abuse of children by poisoning is also highly common with thousands of fatalities. A practical strategy is presented that aims to alert health, forensic, and law enforcement professionals to this problem and to demystify the preconception that it is a rare form of abuse or neglect. Compounds that are foreign to a living organism (xenobiotics) and those present within body (endobiotics), mainly involved in children intoxications and contextual examples related to exposure are also reviewed. Particular concern is given to concepts in the field of children poisoning. The described history and the clinical and toxicological evaluation are discussed, and harmonized protocols regarding correct procedures for sample collection to forensic toxicological analysis are proposed. Since children are particularly vulnerable to the toxic effects of high doses of xenobiotics and endobiotics, special consideration on the preparation of the environment that surrounds children in order minimize all possible risks will be also considered.

Buprenorphine may not be as safe as you think: a pediatric fatality from unintentional exposure

Buprenorphine is a partial μ-opioid receptor agonist that is approved for the treatment of opioid dependency. It is generally believed to be safer than methadone because of its ceiling effect on respiratory depression. As more adults in US households use buprenorphine, an increasing number of children are being exposed. We report a fatal exposure to buprenorphine in a small child that occurred after ingestion of a caretaker's buprenorphine/naloxone. Postmortem toxicology analysis showed free serum concentrations of 52 ng/mL and 39 ng/mL for buprenorphine and norbuprenorphine, respectively. No other drugs were detected. Autopsy did not find signs of injury or trauma. The theoretical safety provided by the ceiling effect in respiratory depression from buprenorphine may not apply to children, and buprenorphine may cause dose-dependent respiratory depression.

Opioid Related Deaths of Infants and Young Children

The prevalence of the opioid drugs is increasing worldwide. Greater access in turn increases the risk of infants and young children being exposed to potentially fatal concentrations of these drugs, either by accident or through the negligent or deliberate actions of a caregiver. This report reviews opioid-related fatalities in this population and discusses homicidal and accidental poisonings and the possible routes of exposure, including through breastfeeding. As with adults, autopsy findings in fatal pediatric opioid toxicity are nonspecific and such cases may mimic death from natural diseases such as metabolic disorders or channelopathies. A detailed review of the case history together with a complete autopsy and toxicology testing are essential for the correct certification of these deaths. Further challenges arise from the fact that toxic ranges for opioids are not well-defined in the pediatric population, and the forensic pathologist must rely on case reports and small case series’ to assist in the determination of “how much is too much”. Resources such as the National Association of Medical Examiners Pediatric Toxicology Registry (NAME PedTox) continue to be of great value, but depend on the voluntary submission of case data from members. Emerging phar-macogenetic data are revealing genetic variations associated with altered metabolism and tissue distribution of opioids; therefore, molecular autopsy techniques should be considered in these challenging cases, especially where the manner of death is unclear.

Respiratory failure caused by a suspicious white powder: a case report of intentional methadone poisoning in an infant

Methadone exposures in children have increased as the drug has gained more prevalence in the treatment of adult narcotic dependency. Previous literature concerning pediatric methadone ingestion has focused primarily on unintentional ingestions. We describe a 2-month-old male infant presenting with respiratory failure from suspected intentional methadone administration. The infant was born to a mother with narcotic dependency and at birth was treated for neonatal abstinence syndrome. After discharge for neonatal abstinence syndrome treatment, the infant continued to be fussy and persistently irritable. We believe the infant was intentionally given methadone at home by his mother for these symptoms. It is important for pediatric providers to be vigilant of households with methadone present. Family-centered education on prevention of methadone ingestion (eg, safe storage) and anticipatory guidance on the signs, symptoms, and treatment of toxicity are key.

Methylnaltrexone in treatment of opioid-induced constipation in a pediatric patient

OBJECTIVES

Opioid-induced constipation persists as a challenge in the management of chronic pain treated with opioid therapy. Multiple opioid antagonists have been applied in attempt to combat the gastrointestinal side effects of opioid analgesia, however their lipid-soluble nature allows passage into the central nervous system and consequent antagonism of centrally mediated analgesia. In contrast, methylnaltrexone offers the advantage of peripheral receptor-specific opioid antagonism due to chemical alterations conferring greater polarity and less lipid solubility. We present use of enteral methylnatrexone to treat severe opioid-induced constipation in a young boy who had failed treatment with the non-specific opioid antagonist, naloxone. This case reports describes the safe transition from enteral naloxone to enteral methylnaltrexone and discusses the potential risk of relative opioid toxicity during the transition.

METHODS

Though methylnaltrexone has approved for subcutaneous use, the characteristics of the patient s disease required enteral administration which had not been described in pediatric dosing. Based on conservative extrapolation of data from adult dosing, a methylnaltrexone dosing regimen was selected and the naloxone was weaned over two days in an effort to avoid a relative opioid overdose.

RESULTS

The patient was successfully transitioned to methylnaltrexone from naloxone over two days. He did experience increased sedation during this time however no severe respiratory depression occurred due to the cessation of chronic central opioid antagonism causing a relative opioid toxicity. Following the institution of methylnaltrexone, his opioid requirement significantly decreased and his gastrointestinal symptoms improved.

DISCUSSION

Our case report demonstrates safe transition from enteral naloxone to enteral methylnaltrexone in a pediatric patient, avoiding the serious consequences of relative opioid toxicity. This patient experienced significant improvement of opioid-induced constipation and reduction in opioid requirements and it is possible that other patients would benefit as well. The role of enteral methylnaltrexone deserves further investigation.

Perioperative pharmacokinetics of methadone in adolescents

BACKGROUND

Methadone is frequently administered to adults experiencing anesthesia and receiving pain treatment. Methadone pharmacokinetics in adults are well characterized, including the perioperative period. Methadone is also used in children. There is, however, no information on methadone pharmacokinetics in children of any age. The purpose of this investigation was to determine the pharmacokinetics of intravenous methadone in children undergoing surgery. Perioperative opioid-sparing effects were also assessed.

METHODS

Eligible subjects were children 5-18 yr undergoing general anesthesia and surgery, with an anticipated postoperative inpatient stay exceeding 3 days. Three groups of 10 to 11 patients each received intravenous methadone hydrochloride after anesthetic induction in ascending dose groups of 0.1, 0.2, and 0.3 mg/kg (up to 20 mg). Anesthetic care was not otherwise changed. Venous blood was obtained for 4 days, for stereoselective determination of methadone and metabolites. Pain assessments were made each morning. Daily and total opioid consumption was determined. Perioperative opioid consumption and pain was determined in a second cohort, which was matched to age, sex, race, ethnicity, surgical procedure, and length of stay, but not receiving methadone.

RESULTS

The final methadone study cohort was 31 adolescents (14 ± 2 yr, range 10-18) undergoing major spine surgery for a diagnosis of scoliosis. Methadone pharmacokinetics were linear over the dose range 0.1-0.3 mg/kg. Disposition was stereoselective. Methadone administration did not dose-dependently affect postoperative pain scores, and did not dose-dependently decrease daily or total postoperative opioid consumption in spinal fusion patients.

CONCLUSIONS

Methadone enantiomer disposition in adolescents undergoing surgery was similar to that in healthy adults.