Methadone analgesia for children with advanced cancer

A Narrative Review of Pain in Pediatric Oncology: The Opioid Option

Opioid therapy is the mainstay for managing pain in pediatric oncology. This narrative review describes the current literature regarding opioids for pediatric cancer pain. The review explores the multifaceted landscape of opioid utilization in this population, including the role of opioids in certain clinical circumstances, modalities of opioid delivery, unique opioids, outpatient and at-home pain management strategies, and other key concepts such as breakthrough pain. This review highlights the importance of individualized dosing and multimodal approaches to enhance efficacy and minimize adverse effects. Drawing from a wide range of evidence, this review offers insights to optimize pediatric oncology pain management.

Methadone for Cancer Pain Management in Children: A Review of Literature

Pain associated with cancer is a common feature among children and adolescents. Among opioids, methadone is a unique drug for its multiple mechanisms of action. Methadone is currently underutilized in children. The use of methadone for cancer pain management in children was assessed in a systematic review. Altogether, 141 children receiving methadone were examined, and another 126 children were assessed for QT prolongation. In the clinical studies, modalities of use, dosing, and duration of assessment were highly variable. In general, methadone was effective and well tolerated with a limited tendency for dose increases. QT prolongation was reported in a percentage of patients independently of the dosages or other variables. The majority of studies considered the use of methadone to be safe and effective in children. Despite methadone possessing interesting properties that make this drug unique in a pediatric context, data is limited, and the literature available is based on retrospective studies. Methadone could be an effective, inexpensive, and versatile medication in children with cancer who have pain. This drug deserves more interest and should prompt studies of better quality with a larger number of patients.

Rediscovery of Methadone to Improve Outcomes in Pain Management

Clinically, methadone is most known for its use in the treatment of opioid maintenance therapy. However, methadone's pharmacological profile makes it an excellent analgesic that can enhance acute and chronic pain management. It is a potent μ-receptor agonist with a longer elimination half-life than most clinically used opioids. In addition, methadone inhibits serotonin and norepinephrine uptake, and it is an N-methyl-D-aspartate antagonist. These distinct analgesic pathways mediate hyperalgesic, allodynic, and neuropathic pain. Its unique analgesic properties provide several essential benefits in perioperative use, neuropathic pain, cancer, and noncancer pain. Despite these proven clinical utilities, methadone has not been used widely to treat acute and chronic pain in opioid naïve patients. This article describes the unique pharmacology of methadone and provides emerging evidence to support its application in acute and chronic pain management. Pain management options and guidelines for surgical patients on methadone are discussed as well.

Managing Pain and Discomfort in Children with Cancer

PURPOSE OF REVIEW

Approximately 15,600 children are diagnosed with cancer annually. Many of these children have cancer-related pain that improves with cancer treatment, but some develop intractable pain from cancer progression or sequelae from treatment modalities. The purpose of this paper is to provide a critical evaluation of the literature relevant to pain management in children with cancer. We intend to emphasize important and up-to-date findings in pharmacology, interventional pain management, and complementary and alternative medicine.

RECENT FINDINGS

Alternative medications and routes of administration, complementary and alternative medicine techniques, and interventional pain procedures offer possible routes for a multi-pronged pediatric cancer pain management plan, although high-level data is often lacking. To improve pediatric cancer pain management, a multifaceted approach embracing the biopsychosocial model of pain is recommended, incorporating evidence-based pharmacology, complementary and alternative medicine techniques, and if needed, interventional pain procedures.

Old Drug, New Pain. Roles and Challenges of Methadone Therapy in Pediatric Palliative Care: A Systematic Review

BACKGROUND

Pediatric palliative care (PPC) is defined as the prevention and relief from suffering of families and children with life-limiting (LLDs) or life-threatening diseases (LTDs). These patients often experience pain, with morphine being the most widely used drug to treat it. Few studies investigated the role of methadone in PPC patients, although it is considered among the most effective and underutilized drugs in PPC.

OBJECTIVES

Our aim was to evaluate the efficacy, safety, and dosage of methadone in PPC.

METHODS

Between August and October 2021 PubMed, Scopus and the Cochrane Library were searched for studies on the use of methadone in children with LLDs and LTDs. Articles were included if they met the following criteria: published in the last 10 years, English language, patients aged 0-23 years; children enrolled in a PPC center or receiving declared support from a PPC service; reporting of specific data on methadone in interventional trials, observational studies, or case series on >10 patients. The reporting of the article was guided by the PRISMA guidelines, and a critical appraisal of the included studies was performed using the JBI-tool.

RESULTS

After duplicates removal and full-text assessment, four studies were included and another one was added after checking the references of the retrieved papers. All were retrospective, and the literature is concordant in documenting the lack of evidence. A total of 116 children received methadone in PPC. From our review emerges the poor quality of data collection: in only one study pain was assessed with standardized scales. All studies documented the effectiveness of methadone in treating complex pain, either nociceptive or neuropathic. No serious adverse events were reported, with no cases of cardiac arrhythmias.

CONCLUSION

Our results suggest that methadone could represent a suitable strategy for treating pain in PPC. However, the evidence base is insufficient, and further research is warranted.

Healthcare interventions improving and reducing quality of life in children at the end of life: a systematic review

BACKGROUND

Children with serious illness suffer from symptoms at the end of life that often fail to be relieved. An overview is required of healthcare interventions improving and decreasing quality of life (QOL) for children with serious illness at the end of life.

METHODS

A systematic review was performed in five databases, January 2000 to July 2018 without language limit. Reviewers selected quantitative studies with a healthcare intervention, for example, medication or treatment, and QOL outcomes or QOL-related measures, for example, symptoms, for children aged 1-17 years with serious illness. One author assessed outcomes with the QualSyst and GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) Framework; two authors checked a 25% sample. QOL improvement or reduction was categorized.

RESULTS

Thirty-six studies met the eligibility criteria studying 20 unique interventions. Designs included 1 randomized controlled trial, 1 cross-sectional study, and 34 cohort studies. Patient-reported symptom monitoring increased QOL significantly in cancer patients in a randomized controlled trial. Dexmedetomidine, methadone, ventilation, pleurodesis, and palliative care were significantly associated with improved QOL, and chemotherapy, stem cell transplant, and hospitalization with reduced QOL, in cohort studies.

CONCLUSIONS

Use of patient-controlled symptom feedback, multidisciplinary palliative care teams with full-time practical support, inhalation therapy, and off-label sedative medication may improve QOL. Curative therapy may reduce QOL.

IMPACT

QOL for children at the end of life may be improved with patient-controlled symptom feedback, multidisciplinary palliative care teams with full-time practical support, inhalation therapy, and off-label sedative medication. QOL for children at the end of life may be reduced with therapy with a curative intent, such as curative chemotherapy or stem cell transplant. A comprehensive overview of current evidence to elevate currently often-failing QOL management for children at the end of life. New paradigm-level indicators for appropriate and inappropriate QOL management in children at the end of life. New hypotheses for future research, guided by the current knowledge within the field. Various healthcare interventions (as described above) could or might be employed as tools to provide relief in QOL management for children with serious illness, such as cancer, at the end of life, and therefore could be discussed in pediatrician end-of-life training to limit the often-failed QOL management in this population, cave the one-size-fits-all approach for individual cases. Multidisciplinary team efforts and 24/7 presence, especially practical support for parents, might characterize effective palliative care team interventions for children with serious illness at the end of life, suggesting a co-regulating link between well-being of the child partly to that of the parents Hypothesis-oriented research is needed, especially for children with nonmalignant disorders, such as genetic or neurological disorders at the end of life, as well as QOL outcomes for intervention research and psychosocial or spiritual outcomes.

The Use of Methadone in Pediatric Cancer Pain - A Retrospective Study from a Governmental Cancer Center in India

Background:

The management of cancer-related pain relies on access to opioids. When regular opioids are not tolerated, or are insufficient, methadone is an affordable and effective analgesic.

Aim:

The aim of the project was to describe the pattern of use and clinical experience of methadone in pediatric cancer pain at a governmental cancer hospital in Hyderabad, one of the four Indian cancer centers with permission to prescribe methadone.

Methods:

This was a retrospective study of medical records of all children, under the age of 18, who had been prescribed methadone from September 9, 2017, to November 19, 2019. Data on analgesic effect, prior and concomitant analgesic treatment, opioid side effects, and the handling of methadone were analyzed.

Results:

A total of 11 children were identified and studied. Methadone was introduced mainly when pain was uncontrolled by regular opioids. Initial daily doses ranged from 1 to 15 mg. The duration of treatment ranged from 7 to 307, with a median of 50 days in the nine patients where treatment exceeded one single dosage. Good analgesic effect was reported in 5/9 children, unchanged from previous analgesic treatment in three patients and without any effect in one child. No severe side effects were reported.

Conclusion:

Low-dose methadone in the treatment of pediatric cancer pain at a low-resource cancer center was safe and well tolerated by the patients, with long treatment durations. It was safely managed, administered with single to double daily dosages, hence easy for patients and family to handle, and an affordable treatment option.

Methadone: applications in pediatric anesthesiology and critical care medicine

Like morphine, methadone is a pure agonist at the µ opioid receptor. However, in distinction to morphine which has an elimination half-life of 2-3 h, methadone has an elimination half-life of 24-36 h. In addition to its effects at the µ opioid receptor, methadone is an antagonist at the N-methyl-D-aspartate (NMDA) receptor and also inhibits the reuptake of the neurotransmitters, serotonin and norepinephrine, in the central nervous system. Given its long half-life and high oral bioavailability, methadone has had a primary role in the outpatient treatment of patients with a history of opioid abuse or addiction. However, its unique pharmacology and cellular effects make it a valuable agent in the treatment of both acute and chronic pain of various etiologies. The following manuscript reviews the pharmacologic properties of methadone and discusses its clinical applications in the practice of pediatric anesthesiology and pediatric critical care medicine.

Methadone for Cancer Pain in Pediatric End-of-Life Care

BACKGROUND

The goal of adequate pain control becomes increasingly salient for children with cancer and their families as the patients approach the end of life. Methadone is one option that is particularly desirable in end-of-life care given its long duration of action and NMDA antagonism that may help in controlling pain refractory to conventional opioids. The purpose of this study was to describe a single institution's experience with methadone for the treatment of cancer pain in pediatric end-of-life care.

METHODS

This retrospective, observational, single-center study included all patients during a 9-year period who died in the inpatient setting and were receiving methadone in their last 30 days of life.

RESULTS

Twenty patients were identified, 18 (90%) of whom received methadone for nociceptive pain. The median duration of methadone use was 32 days (range 2-323 days). Methadone doses ranged from 0.09 to 7.76 mg/kg per day. There were no instances of discontinuing methadone due to an increased QTc interval. No episodes of torsades de pointes were observed.

CONCLUSION

In patients with pediatric cancer who are nearing the end of life, methadone is a valuable adjunctive therapy to treat nociceptive and neuropathic pain and to prevent opioid-induced hyperalgesia and opioid tolerance. An individualized approach to dosage and route should be considered based on specific clinical circumstances.

From Tramadol to Methadone: Opioids in the Treatment of Pain and Dyspnea in Pediatric Palliative Care

BACKGROUND

More than 15,000 children die annually in the United States due to an underlying life-limiting disease and the majority of those children experience distressing symptoms, which are not adequately relieved, such as pain and dyspnea. Multimodal analgesia, that is multiple agents, interventions, rehabilitation, psychological modalities, and integrative (nonpharmacologic) therapies, act synergistically for more effective pediatric pain and symptom control with fewer side effects than a single analgesic or modality. However, opioids, such as morphine, fentanyl, hydromorphone, oxycodone, and methadone (in the United Kingdom: diamorphine) remain the mainstay medication to effectively treat pain and dyspnea in children with serious illness.

METHODS

This article reviews commonly used opioids in Pediatric Palliative Care, which a special emphasis on 2 potentially particularly effective multimechanistic opioids: tramadol and methadone.

RESULTS

Methadone, due to its multimechanistic action profile, is possibly among the most effective and most underutilized opioid analgesics in children with severe unrelieved pain at end of life. However, methadone should not be prescribed by those unfamiliar with its use: Its effects should be closely monitored for several days, particularly when it is first started and after any dose changes.

CONCLUSIONS

Tramadol appears to play a key role in treating episodes of inconsolability in children with progressive neurologic, metabolic, or chromosomally based condition with impairment of the central nervous system. However, the recent 2017 United States Food and Drug Administration (FDA) warning against pediatric use of tramadol does not seem to be based on clinical evidence, and therefore puts children at risk for unrelieved pain or increased respiratory depression.

QT Interval Prolongation in the Pediatric Oncologic Population on Methadone

Studies have been conducted on adults prescribed with methadone to determine the necessary frequency of QTc monitoring but no consensus has been reached and no similar research has been conducted in the pediatric population. The objective of this retrospective study was to determine the occurrence rate of QTc interval prolongation associated with methadone use in a pediatric oncologic population. In total, 18% of patients developed QTc interval prolongation. These patients had longer baseline QTc intervals and were on more QTc interval-prolonging medications. Our data suggest that these variables may be able to risk stratify patients who require more frequent monitoring.

Emerging Challenges to the Safe and Effective Use of Methadone for Cancer-Related Pain in Paediatric and Adult Patient Populations

Methadone continues to be an important medication for the treatment of paediatric and adult cancer-related pain. Appropriate patient selection to ensure safe and effective treatment by a team of clinicians who appreciate and are familiar with methadone and its unique pharmacology is crucial. Unlike morphine and other more common opioids, methadone is purported to have involvement with delta-opioid receptor and higher affinity as an N-methyl-D-aspartate-receptor antagonist. Clinically this gives it the advantage of being effective for both nociceptive and neuropathic pain, but also may be useful in the setting of tolerance to other opioids. Methadone also comes in multiple available formulations that can be administrated through a variety of routes beyond the oral route. Challenges with methadone in treating cancer-related pain include drug interactions specifically as it relates to new targeted cancer therapies. Recent guidelines recommend electrocardiogram monitoring with methadone and there is potential for additive cardiac toxicity in the oncology setting. Appropriate dosing of methadone for pain management given age, organ dysfunction, and patients who are on methadone maintenance therapy are also key factors. This article aims to provide clinicians with evidence and clinical practice guidelines for safe and appropriate use of methadone including indication, initiation, and monitoring given its complexity for management of pain in the dynamic oncology setting.

Corrected QT Interval Prolongation in Pediatric and Young Adult Patients on Methadone for Cancer-Related Pain

CONTEXT

Methadone has been reported to prolong the corrected QT (QTc) interval and increase the risk of torsades de pointes.

OBJECTIVES

Our study examined the frequency of QTc prolongation among pediatric and young adult patients starting methadone for cancer pain.

METHODS

All patients followed a standardized protocol. Electrocardiograms (ECGs) were obtained at baseline (methadone starting day to 14 days prior), 1-2 weeks, and 4-6 weeks later. QTc values were manually calculated using the Bazett formula. QTc prolongation was defined as ≥460 milliseconds (ms) for prepubertal children, ≥470 ms for pubertal males, and ≥480 ms for pubertal females.

RESULTS

Baseline ECGs were completed in 42 patients. Follow-up ECGs were completed in 38 of 42 (91%) and 31 of 42 (74%) patients at 1-2 weeks and 4-6 weeks, respectively. No patients had prolongation of the QTc at baseline, and 1 of 38 (3%) patients had a prolonged QTc at weeks 1-2. This patient had a history of prolonged QTc that the family did not initially report. No patients had prolongation of the QTc at weeks 4-6. No patients had torsades de pointes or ventricular fibrillation, and none died suddenly. Median (interquartile range [IQR]) baseline QTc was 391 (377-400) ms; median (IQR) 1-2 week follow-up QTc was 399 (374-411) ms (P = .05), and median (IQR) 4-6 week follow-up QTc was 393 (379-423) ms (P = .01).

CONCLUSION

Clinically significant prolongation of the QTc interval occurred only in one patient who had a history of prolonged QTc. Prolonged QTc is rare in this population.

Attitudes, Beliefs, and Practices of Pediatric Palliative Care Physicians Regarding the Use of Methadone in Children With Advanced Cancer

CONTEXT

Methadone is a long-acting opioid known for its unique pharmacokinetic and pharmacodynamic properties. Most research on methadone in children is limited to its effect on the prolongation of the corrected QT (QTc) interval.

OBJECTIVES

To better understand the attitudes, beliefs, and practices of pediatric palliative care physicians regarding the use of methadone in children with advanced cancer.

METHODS

A survey was sent to the American Academy of Pediatrics Section of Hospice and Palliative Medicine LISTSERV. Information on demographics, dosing of methadone, and the use of electrocardiograms (ECGs) was collected.

RESULTS

One-hundred and five respondents (91%) provide palliative care to children ≥ 50% of the time, and a majority (81, 77%) prescribe methadone. Most (62, 77%) physicians were board certified in Hospice and Palliative Medicine, and most (39, 63%) certified via the direct pathway ("grandfathering"). Most physicians (57, 70%) do not use loading doses of methadone. Board-certified physicians trended toward decreasing methadone dose more (40% ± 19%) than non-board-certified physicians (28%, ±20%) when changing from the oral to intravenous route (P = 0.07). Respondents defined a QTc interval as "prolonged" (mean ± SD) at 444 milliseconds (±68 milliseconds). The percentage of patients receiving a baseline ECG was 65% (±33%). The most common reason for not performing a baseline ECG was that the patient was on hospice (13, 36%).

CONCLUSIONS

There are consistent practices, attitudes, and beliefs of pediatric palliative care providers with regard to methadone. More education is needed on the accurate value of a prolonged QTc interval.

Methadone for Pain Management in Children with Cancer

Methadone is a synthetic opioid with unique pharmacodynamic and pharmacokinetic properties. It is effective in treating both nociceptive and neuropathic pain, which commonly co-exist in children with cancer. Upon reviewing the literature describing the use of methadone in pediatric oncology patients, publications are limited in number and low in quality of evidence; nevertheless, there is support for the safety and efficacy of methadone in treating pain in children with cancer, particularly when pain is refractory to conventional treatment. Although the risk of life-threatening arrhythmia is commonly cited as an argument against the use of methadone, our review of the literature did not support this finding in children. Further evaluation with prospective studies is warranted to develop evidence-based recommendations for the use of methadone in pediatric oncology.

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.

Practices, Attitudes, and Beliefs of Palliative Care Physicians Regarding the Use of Methadone and Other Long-Acting Opioids in Children with Advanced Cancer

BACKGROUND

Palliative care physicians often assist with pain management in children with cancer, but little is known about how they use long-acting opioids for chronic pain with these patients.

OBJECTIVE

To determine the practices, attitudes, and beliefs of palliative care physicians toward the use of long-acting opioids in children with advanced cancer.

DESIGN

An electronic survey was sent to all members of The American Academy of Pediatrics (AAP) Section of Hospice and Palliative Medicine (SOHPM) and those identified as physicians who provide palliative care to children on the AAP SOHPM LISTSERV^®.

RESULTS

The response rate to the survey was 62% (116/188). A majority (66% [77/116]) of physicians are board certified in both pediatrics and hospice and palliative medicine. This represents 28% of all board-certified pediatric palliative care physicians. Most palliative care physicians report comfort in using long-acting opioids in children (84-94%), with the exception of long-acting hydromorphone (37%). Physicians perceived methadone as least costly (3%) but associated it with a higher perceived family resistance (51%). As compared with pediatric palliative care fellowship-trained physicians, nonpediatric fellowship-trained physicians perceived titration of oxycodone ER and morphine ER to be easier (p = 0.06, p = 0.07) and less likely to agree that the main reason for starting methadone is that the existing formulations of other long-acting opioids are unsuitable for children (p = 0.05).

CONCLUSIONS

Most physicians who provide palliative care to children are comfortable using opioids but there is significant variation in the level of comfort with different opioids. This information will be helpful in developing targeted education for palliative care providers.

Methadone as the Initial Long-Acting Opioid in Children with Advanced Cancer

BACKGROUND

Methadone is an attractive medication for treating children with advanced cancer with pain as it is the only long-acting opioid available as a liquid. However, it is not frequently used due to concerns about potential toxicities and side effects.

OBJECTIVE

Evaluate the efficacy and safety of methadone as the first long-acting opioid in children with advanced cancer.

DESIGN

Retrospective chart review of 52 consecutive patients referred to Pediatric Supportive Care for pain management started on methadone as their first long-acting opioid. Data collected at baseline, follow-up visits #1 (F1) and #2 (F2) included child and parent-reported outcomes for various physical and psychological symptoms, opioid side effects and other clinical data. Symptoms were rated on a 0 (not at all) to 4 (a lot) scale.

RESULTS

Pain (mean ± standard deviation [SD]) scored by the child was 3.6 (±0.6)/4 at baseline and 1.8 (±1.1)/4 at F1 (p < 0.0001). Compared to baseline, pain scored by the child at F2 was 1.2 (±1.3)/4 (p < 0.0001). Pain scored by the parent was 3.5 (±0.7)/4 at baseline and 1.4 (±1.3)/4 at F1 (p < 0.0001). Compared to baseline, pain scored by the parent at F2 was 1.0 (±1.2)/4 (p < 0.0001). Thirty-three (70%) patients at F1 and 23 (79%) patients at F2 did not need a change in dose of methadone. No cardiac arrhythmias or opioid neurotoxicity was observed.

CONCLUSIONS

Initiation of methadone was effective and safe as the first long-acting opioid in children with pain.

When to Use Methadone for pain: A Case-Based Approach

The case studies are written in this article to illustrate how methadone might be used for pain in the Indian context. These cases might be used for discussion in a multidisciplinary team, or for individual study. It is important to understand that pain requires a multidisciplinary approach as opioids will assist only with physical, i.e. neuropathic and nociceptive pain, but not emotional, spiritual, or relational pain or the pain of immobility. The social determinants of pain were included to demonstrate how emotional, relational, and psychological dimensions of pain amplify the physical aspects of pain. The case studies follow a practical step-wise approach to pain while undergoing cancer treatment, pain toward the end-of-life and needing longer acting opioid. Methadone in children, and methadone in conditions of opioid toxicity or where there is a need for absorption in the proximal intestine cases are included.

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.

Extreme doses of intravenous methadone for severe pain in two children with cancer

We describe the effect and side effects in two children with cancer treated with intravenous methadone in extreme doses (>10 mg/kg/day) due to vincristine-induced neuropathy where surgical procedures provoked severe neuropathic pain. The maximum daily dose was 33 and 25 mg/kg/day. Methadone remained effective at adjusted doses. Few side effects were reported. No significant changes in paraclinical data were observed. Prolonged QTc-interval occurred only during concomitant treatment with fluconazole. In conclusion, methadone should be seen as a part of the armamentarium against cancer-related pain. Methadone can be used in extreme doses with appropriate monitoring by clinicians experienced in its use.

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.

Pediatric pain management in palliative care

SUMMARY 

The management of pain in pediatric palliative care (PPC) is essential. Whilst the field of pain management has developed over the years, much of what is done in PPC is based on anecdotal evidence or adult studies. This review explores recent developments in pain management in PPC, in particular the WHO guidelines on the pharmacological treatment of persisting pain in children with medical illnesses. Key issues discussed include the definition, assessment, pharmacological and integrative management of pain, availability of medications, education and research. Whilst advances have been made, including publication of the guidelines, significant gaps exist in terms of the evidence base, education and access to essential medications and both interdisciplinary and international collaboration are required to meet these gaps.

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.

Toward a systematic approach to opioid rotation

Patients requiring chronic opioid therapy may not respond to or tolerate the first opioid prescribed to them, necessitating rotation to another opioid. They may also require dose increases for a number of reasons, including worsening disease and increased pain. Dose escalation to restore analgesia using the primary opioid may lead to increased adverse events. In these patients, rotation to a different opioid at a lower-than-equivalent dose may be sufficient to maintain adequate tolerability and analgesia. In published trials and case series, opioid rotation is performed either using a predetermined substitute opioid with fixed conversion methods, or in a manner that appears to be no more systematic than trial and error. In clinical practice, opioid rotation must be performed with consideration of individual patient characteristics, comorbidities (eg, concurrent psychiatric, pulmonary, renal, or hepatic illness), and concurrent medications, using flexible dosing protocols that take into account incomplete opioid cross-tolerance. References cited in this review were identified via a search of PubMed covering all English language publications up to May 21, 2013 pertaining to opioid rotation, excluding narrative reviews, letters, and expert opinion. The search yielded a total of 129 articles, 92 of which were judged to provide relevant information and subsequently included in this review. Through a review of this literature and from the authors’ empiric experience, this review provides practical information on performing opioid rotation in clinical practice.

Pain care for patients with epidermolysis bullosa: best care practice guidelines

BACKGROUND

Inherited epidermolysis bullosa (EB) comprises a group of rare disorders that have multi-system effects and patients present with a number of both acute and chronic pain care needs. Effects on quality of life are substantial. Pain and itching are burdensome daily problems. Experience with, and knowledge of, the best pain and itch care for these patients is minimal. Evidence-based best care practice guidelines are needed to establish a base of knowledge and practice for practitioners of many disciplines to improve the quality of life for both adult and pediatric patients with EB.

METHODS

The process was begun at the request of Dystrophic Epidermolysis Bullosa Research Association International (DEBRA International), an organization dedicated to improvement of care, research and dissemination of knowledge for EB patients worldwide. An international panel of experts in pain and palliative care who have extensive experience caring for patients with EB was assembled. Literature was reviewed and systematically evaluated. For areas of care without direct evidence, clinically relevant literature was assessed, and rounds of consensus building were conducted. The process involved a face-to-face consensus meeting that involved a family representative and methodologist, as well as the panel of clinical experts. During development, EB family input was obtained and the document was reviewed by a wide variety of experts representing several disciplines related to the care of patients with EB.

RESULTS

The first evidence-based care guidelines for the care of pain in EB were produced. The guidelines are clinically relevant for care of patients of all subtypes and ages, and apply to practitioners of all disciplines involved in the care of patients with EB. When the evidence suggests that the diagnosis or treatment of painful conditions differs between adults and children, it will be so noted.

CONCLUSIONS

Evidence-based care guidelines are a means of standardizing optimal care for EB patients, whose disease is often times horrific in its effects on quality of life, and whose care is resource-intensive and difficult. The guideline development process also highlighted areas for research in order to improve further the evidence base for future care.

Drugs for chronic pain in children: a commentary on clinical practice and the absence of evidence

Pediatric chronic pain is widespread, under-recognized and undertreated. Best management usually involves a multimodal approach coordinated by a multidisciplinary team. The present commentary specifically discusses common pharmacological approaches to chronic pain in children, identifies gaps in knowledge and suggests several research directions that would benefit future clinical care.

Attitudes and practices of pediatric oncologists regarding methadone use in the treatment of cancer-related pain: results of a North American Survey

Methadone is effective in the treatment of cancer-related pain in adults. Pediatric oncologists may be reluctant to use methadone, given the paucity of existing research and a lack of familiarity with its use. This study's purpose was to assess pediatric oncologists' experience, comfort and practice of methadone prescription, and determine interest in and appropriate venues for education on methadone. A 22-item survey was sent by electronic mail to 1912 practicing pediatric oncologists. Six hundred thirty-one pediatric oncologists (33%) responded to the survey. Seventy-two percent of respondents reported they prescribe methadone to <10% of their patients receiving opioids. Physicians practicing ≥10 years (84% vs. 76%, P=0.01), at centers that see ≥100 new patients per year (86% vs. 76%, P=0.003), or who have received prior education on methadone (89% vs. 54%, P<0.001) were more likely to have prescribed methadone. The primary reasons respondents did not utilize methadone included a lack of knowledge of methadone's pharmacodynamics (39%), effectiveness (39%), and/or dosing equivalence (34%). Perceived competence with dose equivalence, belief that methadone is effective, and working in a division where >20 patients per year died were all independently associated with having prescribed methadone to >10% of patients on opioids. Eighty-five percent of respondents would like additional education on methadone. Many pediatric oncologists lack experience and education in the use of methadone. Formal education initiatives should be implemented to enhance pediatric oncologists' comfort and expertise in methadone use.

Severe central sleep apnea in a child with leukemia on chronic methadone therapy

We describe a child with acute myeloid leukemia (AML) who developed severe central sleep apnea (CSA) on methadone therapy for chronic pain management. His chemotherapy-related cerebral atrophy and renal insufficiency with impaired methadone clearance may have also contributed to the severity of his sleep-disordered breathing. Maintenance methadone treatment is not a common pediatric practice; therefore, the adverse effects of methadone therapy, including CSA, are rarely reported in children.

Perioperative management of the child on long-term opioids

The strategies used to manage children exposed to long-term opioids are extrapolated from adult literature. Opioid consumption during the perioperative period is more than three times that observed in patients not taking chronic opioids. A sparing use of opioids in the perioperative period results in both poor pain management and withdrawal phenomena. The child's pre-existing opioid requirement should be maintained, and acute pain associated with operative procedures should be managed with additional analgesia. This usually comprises short-acting opioids, regional or local anesthesia, and adjuvant therapies. Long-acting opioids, transdermal opioid patches, and implantable pumps can be used to maintain the regular opioid requirement. Intravenous infusion, nurse controlled analgesia, patient-controlled analgesia, or oral formulations are invaluable for supplemental requirements postoperatively. Effective management requires more than simply increasing opioid dose during this time. Collaboration of the child, family, and all teams involved is necessary. While chronic pain or palliative care teams and other staff experienced with the care of children suffering chronic pain may have helpful input, many pediatric hospitals do not have chronic pain teams, and many patients receiving long-term opioids are not palliative. Acute pain services are appropriate to deal with those on long-term opioids in the perioperative setting and do so successfully in many centers. Staff caring for such children in the perioperative period should be aware of the challenges these children face and be educated before surgery about strategies for postoperative management and discharge planning.

Methadone use in children and young adults at a cancer center: a retrospective study

OBJECTIVE

To augment the literature on methadone applications in pediatric oncology, the authors reviewed the use of methadone at a pediatric cancer center over a 5-year period.

DESIGN AND SETTING

Forty-one patients received methadone for inpatient or outpatient pain management. The authors retrospectively reviewed their demographic characteristics, diagnoses, type of pain (nociceptive, neuropathic, or mixed) and causes of pain, and the indications, dose regimens, adverse effects, and outcomes of methadone treatment.

RESULTS

There were four types of clinical uses for methadone in 41 patients (10 patients had two): nociceptive pain unresponsive to other opioids (17 patients, 33.3 percent), neuropathic pain (20 patients, 39.2 percent), facilitation of weaning from opioids (11 patients, 21.6 percent), and end-of-life pain management (3 patients, 5.9 percent). The mean age of the 24 males (58.5 percent) and 17 females (41.5 percent) at the start of treatment was 15.7 years (range, 0.6-23 years). The most common diagnoses were leukemia (n = 10, 24.4 percent), osteosarcoma (n = 7, 17.0 percent), and rhabdomyosarcoma (n = 5, 12.2 percent). The causes of pain were bone marrow transplant (n = 13, 31.7 percent), amputation (n = 6, 14.6 percent), chemotherapy (n = 5, 12.2 percent), tumor (n = 5, 12.2 percent), limb-sparing surgery (n = 4, 9.8 percent), and other (n = 8, 19.5 percent). Efficacy was assessed at the end (or after 6 months) of methadone treatment. For many patients (43.1 percent), methadone showed efficacy in achieving the purpose for which it was prescribed, including reduction of nociceptive or neuropathic pain and prevention of opioid withdrawal. Sedation was the most common side effect (24.4 percent).

CONCLUSIONS

Methadone was effective for pediatric patients with neuropathic pain or nociceptive pain unresponsive to other opioids, and it effectively prevented opioid withdrawal.

Role of Palliative Care in Adolescent and Young Adult Oncology

Adolescents and young adults (AYAs) with cancer are a heterogeneous group. Nevertheless, there are sufficient unifying characteristics to form a distinct clinical entity. Management of this special group requires a broad-based interdisciplinary clinical team, which should include palliative care (PC), psychology, social work, oncology, and nursing representatives. The function of PC is to provide impeccable pain and other symptom control and to coordinate care as the disease progresses. Features unique to AYAs with cancer include the psychosocial developmental phases, a young person facing death, grief, and bereavement. Pharmacologic and medical interventions by PC in AYAs are broadly similar to adults. Developing trust and being flexible are key skills that PC must use with AYAs. There is a paucity of high-quality controlled studies in the PC literature in general and AYA-PC in particular. Therefore, the methodology of this article is largely based on the narrative and clinical experience. The experience is based on clinicians' work with AYAs with cancer in Israel and Australia. Clinical lessons will be drawn by comparing and contrasting the cultures. Nevertheless, most PC clinical interventions, both pharmacologic and psychosocial, are derived from literature where there is a good evidence base. Future development of PC within AYAs should be coordinated at a national level via appropriate palliative and oncology professional organizations.

The role of methadone in cancer pain treatment--a review

BACKGROUND

Methadone is an opioid analgesic of step 3 of the World Health Organization (WHO) analgesic ladder.

AIM AND METHODS

To outline pharmacodynamics, pharmacokinetics, drug interactions, equianalgesic dose ratio with other opioids, dosing rules, adverse effects and methadone clinical studies in patients with cancer pain. A review of relevant literature on methadone use in cancer pain was conducted.

RESULTS

Methadone is used in opioid rotation and administered to patients with cancer pain not responsive to morphine or other strong opioids when intractable opioid adverse effects appear. Methadone is considered as the first strong opioid analgesic and in patients with renal impairment. Methadone possesses different pharmacodynamics and pharmacokinetics in comparison to other opioids. The advantages of methadone include multimode analgesic activity, high oral and rectal bioavailability, long lasting analgesia, lack of active metabolites, excretion mainly with faeces, low cost and a weak immunosuppressive effect. The disadvantages include long and changeable plasma half-life, high bound to serum proteins, metabolism through P450 system, numerous drug interactions, lack of clear equianalgesic dose ratio to other opioids, QT interval prolongation, local reactions when administered subcutaneously.

CONCLUSIONS

Methadone is an important opioid analgesic at step 3 of the WHO analgesic ladder. Future controlled studies may focus on establishment of methadone equianalgesic dose ratio with other opioids and its role as the first strong opioid in comparative studies with analgesia, adverse effects and quality of life taken into consideration.