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

Polypharmacy and Reversible Drug Induced QT Prolongation in a Patient with Advanced Cancer: Case Report

QT prolongation is related to the development of ventricular arrhythmias such as Torsade de Pointes (TdP) that can lead to sudden cardiac death. Several drugs used in the treatment of patients with advanced cancer may induce QT prolongation due to their interference with cardiac ion channels. Some patients may be at higher risk if predisposing factors are present. Herein we present the case of a patient with advanced cancer under anti-tumor treatment with radical intention that developed a reversible drug-induced QT prolongation when simultaneously treated with methadone, haloperidol and fluoxetine that presented with chest pain and bradycardia. An approach to cancer patients at risk for drug-induced QT prolongation is discussed highlighting the need of a thorough medication review with a special focus in the patient with polypharmacy.

Methadone switching for refractory cancer pain

BACKGROUND

Methadone is commonly considered an alternative opioid treatment for refractory cancer pain. This study aims to investigate the efficacy, safety, and cost of methadone in the treatment of refractory cancer pain.

METHODS

A retrospective study was conducted in patients who used methadone for refractory cancer pain from April 2016 to December 2020 at a cancer specialized hospital. Pain control, evaluated via pain score and breakthrough pain frequency, and adverse events of methadone were compared with analgesic regimens prior to methadone administration. The factors potentially affecting the switching outcome were analyzed via multivariate analysis. Moreover, the cost of pain control was estimated.

RESULTS

Ninety patients received methadone for poor pain control (74.4%), intolerable adverse events (10.0%), or both (15.6%) after prior opioid treatments. Sixty-four patients (71.1%) were successfully switched to methadone with median pain score significantly decreased from 4.0 to 2.0 (p < 0.001) and median daily frequency of breakthrough pain from 3.0 to 0.0 (p < 0.001) at a maintained median conversion ratio of 6.3 [interquartile range (IQR): 4.0-10.0] to prior opioid treatment. Similar adverse event profiles of constipation, nausea, vomiting, and dizziness were observed between methadone and prior opioid regimens. The median daily cost of analgesic regimens was significantly reduced from $19.5 (IQR: 12.3-46.2) to $10.8 (IQR: 7.1-18.7) (p < 0.01) after switching to methadone. The 3-day switch method significantly improved the rate of successful switching compared with the stop and go method (odds ratio = 3.37, 95% CI: 1.30-8.76, p = 0.013).

CONCLUSION

Methadone is an effective, safe, and cost-saving treatment for patients with refractory cancer pain.

Management of opioid use disorder and associated conditions among hospitalized adults: A Consensus Statement from the Society of Hospital Medicine

Hospital-based clinicians frequently care for patients with opioid withdrawal or opioid use disorder (OUD) and are well-positioned to identify and initiate treatment for these patients. With rising numbers of hospitalizations related to opioid use and opioid-related overdose, the Society of Hospital Medicine convened a working group to develop a Consensus Statement on the management of OUD and associated conditions among hospitalized adults. The guidance statement is intended for clinicians practicing medicine in the inpatient setting (e.g., hospitalists, primary care physicians, family physicians, advanced practice nurses, and physician assistants) and is intended to apply to hospitalized adults at risk for, or diagnosed with, OUD. To develop the Consensus Statement, the working group conducted a systematic review of relevant guidelines and composed a draft statement based on extracted recommendations. Next, the working group obtained feedback on the draft statement from external experts in addiction medicine, SHM members, professional societies, harm reduction organizations and advocacy groups, and peer reviewers. The iterative development process resulted in a final Consensus Statement consisting of 18 recommendations covering the following topics: (1) identification and treatment of OUD and opioid withdrawal, (2) perioperative and acute pain management in patients with OUD, and (3) methods to optimize care transitions at hospital discharge for patients with OUD. Most recommendations in the Consensus Statement were derived from guidelines based on observational studies and expert consensus. Due to the lack of rigorous evidence supporting key aspects of OUD-related care, the working group identified important issues necessitating future research and exploration.

The Use of Low-Dose Methadone as Add-On to Ongoing Opioid Treatment in Palliative Cancer Care—An Underrated Treatment?

The aim of this review is to summarize the current knowledge of low-dose methadone treatment in palliative cancer care. In Sweden, methadone is quite common in specialized palliative care, where almost a tenth of patients are prescribed this drug. Negative attitudes towards methadone do not seem to prevent it from being used for pain management, and by starting with low doses and then increasing slowly and gradually, methadone can apparently be introduced safely. It is still uncertain whether methadone has a better analgesic effect than other opioids. However, for pain relief in cancer patients with severe and complex cancer-related pain, NMDA receptor inhibition with methadone may, in selected cases, be an attractive alternative, especially in the form of low-dose supplements to other ongoing opioids. Due to long half-life and complex metabolism, the use of methadone requires an experienced physician and solid follow-up. Continuous administration of opioids, including low-dose methadone, has been proven effective and safe in reducing pain in dying patients without increasing the risk of confusion, regardless of age.

Methadone Switching for Cancer Pain: A New Classification of Initiation Protocols, Based on a Critical Literature Review

Background: The initiation of methadone, a known effective analgesic for cancer pain, is complex. The existing protocols are often inadequately described; therefore, a classification of literature is needed. We reviewed and classified the recent literature on methadone initiation protocols in cancer patients experiencing severe pain. Objective: To provide a new classification of initiation protocols, based on a critical literature review. Data Sources: The MEDLINE database was searched for articles published until March 25, 2021, using the terms "cancer pain," "methadone," "methadone introduction," or "methadone initiation." The search was limited to human studies, randomized controlled trials (RCTs), other clinical trials, meta-analyses, and case reports. Selected articles were assessed for initiation details (rapid or progressive), administered dose (fixed rescue dose or ad libitum), and dose calculation (fixed or progressive ratios using morphine equivalent daily dose [MEDD] for daily or unitary dose). Results: Twenty-four publications that met our inclusion criteria were analyzed. No large-scale prospective double-blind RCTs with robust design were identified. Most studies assessed relatively small numbers of patients. Eight initiation types were identified, of which three involved seven "high quality" studies: "rapid switch-fixed doses and rescue dose-progressive daily ratio," "progressive switch-fixed dose and rescue dose-progressive daily ratio," and "rapid switch-ad libitum-fixed ratio for unitary dose" protocols. This classification provides the latest information on methadone initiation protocols. The total daily dose of methadone varied largely across protocols. Conclusion: We recommend a maximal daily methadone dose of 100 mg (3 doses of 30 mg or 5 doses of 20 mg) for MEDD <500 mg, when the two "ad libitum" protocols are used. Further clinical research on this topic is warranted.

A Randomized Controlled Trial Evaluating the Analgesic Effect of the Combination of Methadone With Morphine for Cancer Related Pain

CONTEXT AND OBJECTIVES

Although opioids play an indispensable role in the management of cancer-related pain, inadequate pain relief still occurs. The primary objective of this study was to evaluate whether the combination of a low dose of methadone with morphine promotes a reduction in opioid consumption; the secondary objectives were if the association promotes lower pain intensity, and adverse effects (AEs).

MATERIALS AND METHODS

A sample if 41 patients with cancer-related pain in palliative setting were included. Patients were starting the third step of the analgesic ladder, and 1 group (n=21) achieve methadone (2.5 mg/12 h) in combination with morphine/methadone, and another group (n=20) received morphine alone. Both groups could use morphine (5 mg) as needed to maintain pain intensity <4, and adjuvant in stable dose. The following outcomes were evaluated: total morphine dose, pain intensity, and AEs.

RESULTS

There was no difference in the number of adjuvants, and the dose of morphine used. Pain intensity was significantly lower in the morphine/methadone group after 2 weeks, with no statistically significant difference at other timepoints. There was no difference between groups in the AEs.

CONCLUSION

Low dose of methadone in combination with morphine provided faster pain control as compared with morphine alone, and although this study was not powered to show differences in AEs, we did not notice a difference.

Pharmacogenomics of methadone: a narrative review of the literature

Background: Methadone, a synthetic opioid with longer duration of action and lower abuse potential compared with morphine, is used to prevent opioid withdrawal, as well as to manage chronic and acute surgical pain. The variability in response to methadone has been widely recognized. The purpose of this article is to review the literature on the pharmacogenetic factors underlying this variability. Materials & methods: This is a narrative overview of the literature on the genetic variants affecting pharmacodynamics and pharmacokinetics of methadone, retrieved from searches of databases such as PubMed and google scholar. Discussion: Clinical responses to methadone may be affected by genetic variants in the opioidergic, dopaminergic and neurotrophic pathways. Polymorphisms in genes related to disposition and elimination of methadone alter the pharmacokinetics, and possibly pharmacodynamics of methadone. Cytochrome P450 enzymes and P-glycoprotein variants contribute to the interindividual variability in methadone pharmacokinetics. Evidence for single gene variants affecting methadone response remains weak. Multiple genetic variants must be considered in conjunction to improve predictive ability. Conclusion: Evidence remains scarce at this time, to recommend pharmacogenetic testing before methadone administration. Well-powered clinical studies are needed with population pharmacokinetic-pharmacodynamic modeling and multigenetic signature-based predictions to enable tailored use of methadone in clinical practice.

Suppressor capacity of copper nanoparticles biosynthesized using Crocus sativus L. leaf aqueous extract on methadone-induced cell death in adrenal phaeochromocytoma (PC12) cell line

In this research, we prepared and formulated a neuroprotective supplement (copper nanoparticles in aqueous medium utilizing Crocus sativus L. Leaf aqueous extract) for determining its potential against methadone-induced cell death in PC12. The results of chemical characterization tests i.e., FE-SEM, FT-IR, XRD, EDX, TEM, and UV–Vis spectroscopy revealed that the study showed that copper nanoparticles were synthesized in the perfect way possible. In the TEM and FE-SEM images, the copper nanoparticles were in the mean size of 27.5 nm with the spherical shape. In the biological part of the present research, the Rat inflammatory cytokine assay kit was used to measure the concentrations of inflammatory cytokines. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) test was used to show DNA fragmentation and apoptosis. Caspase-3 activity was assessed by the caspase activity colorimetric assay kit and mitochondrial membrane potential was studied by Rhodamine123 fluorescence dye. Also, the cell viability of PC12 was measured by trypan blue assay. Copper nanoparticles-treated cell cutlers significantly (p ≤ 0.01) decreased the inflammatory cytokines concentrations, caspase-3 activity, and DNA fragmentation and they raised the cell viability and mitochondrial membrane potential in the high concentration of methadone-treated PC12 cells. The best result of neuroprotective properties was seen in the high dose of copper nanoparticles i.e., 4 µg. According to the above results, copper nanoparticles containing C. sativus leaf aqueous extract can be used in peripheral nervous system treatment as a neuroprotective promoter and central nervous system after approving in the clinical trial studies in humans.

The role of methadone in cancer-induced bone pain: a retrospective cohort study

PURPOSE

Cancer-induced bone pain (CIBP) can be challenging to manage in advanced cancer. The unique properties of methadone may have a role in refractory CIBP. We aimed to evaluate the analgesic effects of methadone for CIBP when other opioids are ineffective or intolerable.

METHODS

A retrospective study of palliative care inpatients rotated to methadone from another opioid for CIBP over a 4-year period. Primary outcome was ≥ 30% reduction in pain intensity (11-point numeric rating scale) from baseline to completion of methadone rotation (MR). Secondary outcomes were ≥ 50% reduction in pain intensity and changes in long-acting and breakthrough opioid requirements.

RESULTS

Ninety-four eligible patients completed MR for the following reasons: poor pain control (72.3%), opioid toxicities (4.3%) or both (23.4%). On completion of MR, 70.2% and 53.2% achieved a ≥ 30% and ≥ 50% reduction in pain respectively, with mean pain intensity score reduced from 5.6 (SD = 2.1) at baseline to 2.6 (SD = 2.5) (p < 0.001). Mean calculated daily methadone dose pre-MR was 25.7 mg (SD = 10.9), with 72.3% of patients requiring a lower dose on completion of MR (mean 17.0 mg, SD = 8.5). The mean number of breakthrough opioid analgesia used a day reduced from 3.4 (SD = 2.3) to 1.8 (SD = 1.7) (p < 0.001).

CONCLUSIONS

MR for CIBP may result in reduction in pain intensity, when other opioids are ineffective or intolerable, with patients requiring reduced overall dosing of their long-acting opioid and frequency of breakthrough opioid use.

Methadone in Cancer Pain

Methadone has been an unique, versatile, cost effective, synthetic opioid utilized in nociceptive as well as neuropathic pain. Pain and palliative care physicians started accepting methadone in treatment of complex pain associated with advanced cancer and neuropathic pain syndromes in which conventional opioids were no longer effective. The challenge is in accepting methadone as a main stream first line opioid, from being considered as a second line replacement/substitution drug all these years. Methadone has a significant role as opioid rotation in refractory cancer pain, especially when started early leading to successful conversion. Advantages of methadone in paediatric patients with advanced cancer were its safety and efficacy as a first-choice opioid, availability as a liquid formulation and its infrequent dose requirements. Methadone is neither recommended nor justified to be used as an anti-cancer drug and its role as an anti-cancer agent is a misconception. Many guidelines were proposed after 2008 to address methadone safety. Most of them emphasized on prevention of cardiac arrhythmia and association of methadone with QTc prolongation rather than address the real issue. Methadone has been established to be safe when used in opioid naïve patients with careful titration instituted in an ambulatory setting and has equal success in opioid rotation in outpatient setup. Methadone prescription should be carried out by experienced pain and palliative care providers with careful dose titration and clinical monitoring.

A single-institution, randomized, pilot study evaluating the efficacy of gabapentin and methadone for patients undergoing chemoradiation for head and neck squamous cell cancer

BACKGROUND

The objective of the current study was to compare the safety and efficacy between 2 analgesic regimens for patients with head and neck cancer (HNC) undergoing definitive chemoradiation (CRT).

METHODS

The current study was a prospective, single-institution, 2-arm, randomized pilot study. Patients with American Joint Committee on Cancer seventh edition stage II to stage IV squamous cell carcinoma of the head and neck who were undergoing CRT were randomized to either arm 1, which entailed high-dose gabapentin (2700 mg daily) with the institutional standard of care (hydrocodone and/or acetaminophen progressing to fentanyl as needed), or arm 2, which comprised low-dose gabapentin (900 mg daily) with methadone. The primary endpoints were safety and toxicity. Secondary endpoints were pain, opioid requirement, and quality of life (QOL). Differences between the treatment arms at multiple time points were compared using a generalized linear mixed regression model with Sidak correction.

RESULTS

A total of 60 patients (31 in arm 1 and 29 in arm 2) were enrolled from April 2015 to August 2017. There was no difference between the treatment arms with regard to adverse events or serious adverse events. Pain was not found to be different between the treatment arms. More patients in arm 1 did not require an opioid during treatment (42% vs 7%; P = .002). Patients in arm 2 experienced significantly better QOL outcomes across multiple domains, including overall health (P = .05), physical functioning (P = .04), role functioning (P = .01), and social functioning (P = .01).

CONCLUSIONS

High-dose prophylactic gabapentin increased the percentage of patients who required no opioid during treatment. Methadone may improve QOL compared with a regimen of short-acting opioids and fentanyl. However, pain was found to significantly worsen throughout treatment regardless of treatment arm, necessitating further studies to identify a more optimal regimen.

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.

Delay-Dependent Impairments in Memory and Motor Functions After Acute Methadone Overdose in Rats

Methadone is used as a substitution drug for the treatment of opioid dependence and chronic pain. Despite its widespread use and availability, there is a serious concern with respect to the relative safety of methadone. The purpose of this study was to characterize how acute methadone overdose affects the cognitive and motor performance of naïve healthy rats. The methadone overdose was induced by administering an acute toxic dose of methadone (15 mg/kg; ip; the equivalent dose of 80% of LD50) to adolescent rats. Resuscitation using a ventilator pump along with a single dose of naloxone (2 mg/kg; ip) was administered following the occurrence of apnea. The animals which were successfully resuscitated divided randomly into three apnea groups that evaluated either on day 1, 5, or 10 post-resuscitation (M/N-Day 1, M/N-Day 5, and M/N-Day 10 groups) in the Y-maze and novel object memory recognition tasks as well as pole and rotarod tests. The data revealed that a single toxic dose of methadone had an adverse effect on spontaneous behavior. In addition, Recognition memory impairment was observed in the M/N-Day 1, 5, and 10 groups after methadone-induced apnea. Further, descending time in the M/N-Day 5 group increased significantly in comparison with its respective Saline control group. The overall results indicate that acute methadone-overdose-induced apnea produced delay-dependent cognitive and motor impairment. We suggest that methadone poisoning should be considered as a possible cause of delayed neurological disorders, which might be transient, in some types of memory or motor performance in naïve healthy rats.

Update in Hospital Palliative Care: Symptom Management, Communication, Caregiver Outcomes, and Moral Distress

BACKGROUND

Updated knowledge of the palliative care (PC) literature is needed to maintain competency and best address the PC needs of hospitalized patients. We critiqued the recent PC literature with the highest potential to impact hospital practice.

METHODS

We reviewed articles published between January 2016 and December 2016, which were identified through a handsearch of leading journals and a MEDLINE search. The final 9 articles selected were determined by consensus based on scientific rigor, relevance to hospital medicine, and impact on practice.

RESULTS

Key findings include the following: scheduled antipsychotics were inferior to a placebo for nonterminal delirium; a low-dose morphine was superior to a weak opioid for moderate cancer pain; methadone as a coanalgesic improved high-intensity cancer pain; many hospitalized patients on comfort care still receive antimicrobials; video decision aids improved the rates of advance care planning (ACP) and hospice use and decreased costs; standardized, PC-led intervention did not improve psychological outcomes in families of patients with a chronic critical illness; caregivers of patients surviving a prolonged critical illness experienced high and persistent rates of depression; people with non-normative sexuality or gender faced additional stressors with partner loss; and physician trainees experienced significant moral distress with futile treatments.

CONCLUSIONS

Recent research provides important guidance for clinicians caring for hospitalized patients with serious illnesses, including symptom management, ACP, moral distress, and outcomes of critical illness.

Methadone against cancer: Lost in translation

Recently, the opioid analgesic d,l-methadone has gained much attention as a potential antineoplastic compound, considerably triggered through lay press and media. In consequence, physicians and pharmacists are currently confronted with numerous patients willing to use d,l-methadone against their malignancies. Well-performed in vitro and in vivo models have in fact shown pro-apoptotic effects of d,l-methadone or other opioids, but also proliferation-stimulating properties. Moreover, the mechanisms of proposed opioid-stimulated apoptosis are incompletely described or contradicting. Finally, the receptors mostly responsible for induction of apoptosis by d,l-methadone remain unclear as contributions of both µ-opioid receptors, Fas cell death receptors, toll-like receptors, N-Methyl-d-aspartate receptors and opioid growth factor receptors were suggested. Such ambiguity prevents rational application of d,l-methadone or patient stratification to enhance beneficial antineoplastic effects. From a clinical point of view, d,l-methadone and other opioids might in fact prolong survival, but such effects likely originate from their analgesic and neuro-psychotropic properties and, thus, improvements of quality of life. Crucial obstacles to the administration of d,l-methadone are incomplete knowledge about its systemic disposition, highly variable pharmacokinetics, profound drug-drug- or drug-disease interaction and QT-prolongation potential. This article summarizes and rates the pharmacological basis of d,l-methadone as an antineoplastic agent and puts its administration in clinical oncology into perspective. Despite enthralling experimental findings about d,l-methadone-mediated apoptosis in cancerous cells or tissues, clinicians should realize the current lack of evidence for the use of d,l-methadone as an antineoplastic agent. Its administration against cancer pain is, however, tenable, albeit restricted to certain clinical situations.

Challenges of Using Methadone in the Indian Pain and Palliative Care Practice

Palliative care providers across India lobbied to gain access to methadone for pain relief and this has finally been achieved. Palliative care activists will count on the numerous strengths for introducing methadone in India, including the various national and state government initiatives that have been introduced recognizing the importance of palliative care as a specialty in addition to improving opioid accessibility and training. Adding to the support are the Non-Governmental Organizations (NGOs), the medical fraternity and the international interactive and innovative programs such as the Project Extension for Community Health Outcome. As compelling as the need for methadone is, many challenges await. This article outlines the challenges of procuring methadone and also discusses the challenges specific to methadone. Balancing the availability and diversion in a setting of opioid phobia, implementing the amended laws to improve availability and accessibility in a country with diverse health-care practices are the major challenges in implementing methadone for relief of pain. The unique pharmacology of the drug requires meticulous patient selection, vigilant monitoring, and excellent communication and collaboration with a multidisciplinary team and caregivers. The psychological acceptance of the patient, the professional training of the team and the place where care is provided are also challenges which need to be overcome. These challenges could well be the catalyst for a more diligent and vigilant approach to opioid prescribing practices. Start low, go slow could well be the way forward with caregiver education to prescribe methadone safely in the Indian palliative care setting.

Overall Survival among Cancer Patients Undergoing Opioid Rotation to Methadone Compared to Other Opioids

BACKGROUND

Methadone has been associated with lower overall survival (OS) in patients with chronic pain. There are no data available on the association of methadone with OS in cancer patients.

OBJECTIVE

Our aim was to compare the OS in cancer outpatients undergoing opioid rotation (OR) to methadone and other strong opioids.

DESIGN

Demographics, symptoms, and morphine equivalent daily dose (MEDD) were collected in patients who underwent OR from strong opioids to either methadone or other strong opioids and returned for a follow-up within six weeks.

SETTING/SUBJECTS

Nine hundred thirty-eight consecutive outpatients to the supportive care center of a tertiary cancer center were reviewed.

MEASUREMENTS

Kaplan-Meier curves were used to evaluate survival.

RESULTS

Of a total of 164 eligible patients, 54/76 patients who underwent OR to methadone and 48/88 patients who underwent OR to other opioids returned for a follow-up visit. The median age was 56 years, 54% were male, and 87% had advanced cancer. There were no significant differences between the two groups in patient characteristics, performance status, MEDD, and pain scores. The Kaplan-Meier curves revealed no significant difference in median OS between all patients undergoing OR to methadone and other opioids [3.75 months (95% confidence interval, CI, 2.30-6.46) vs. 2.62 months (95% CI 1.74-4.33); p = 0.35] and also among those who returned for a follow-up following an OR to methadone and other opioids [5.15 months (95% CI 3.64-7.41) vs. 5.90 months (95% CI 2.62-9.28); p = 0.89].

CONCLUSIONS

We observed no significant difference in OS in cancer patients in methadone group compared to other opioids.

Efficacy and Safety of Two Methadone Titration Methods for the Treatment of Cancer-Related Pain: The EQUIMETH2 Trial (Methadone for Cancer-Related Pain)

CONTEXT

In the European Association for Palliative Care recommendations for cancer pain management, there was no consensus regarding the indications, titration, or monitoring of methadone.

OBJECTIVES

This national, randomized, multicenter trial aimed to compare two methadone titration methods (stop-and-go vs. progressive) in patients with cancer-related pain who were inadequately relieved by or intolerant to Level 3 opioids.

METHODS

The primary end point was the rate of success/failure at Day 4, defined as pain relief (reduction of at least two points on the visual scale and a pain score <5 for two consecutive days) and no overdose (Rudkin scale ≥3 and respiratory rate <8/minute). The patients were followed for two months after enrollment.

RESULTS

The cancer-related pain characteristics of the 146 patients were as follows: 16% were nociceptive, 85% experienced breakthrough pain, and 84% had mixed types of pain. The reasons for switching to methadone were a lack of efficacy that was either isolated (56%) or associated with intolerance (38%). Adequate pain relief was obtained in 80% of the patients (median of three days in both groups [P = 0.12]) and lasted until D56. The rate of success/failure was approximately 40% at Day 4 in both groups, with overdoses in 13% of the patients throughout the study. The two methods were considered equally easy to perform by nearly 60% of the clinicians.

CONCLUSION

Methadone is an effective and sustainable second-line alternative opioid for the treatment of cancer-related pain. The methods of titration are comparable in terms of efficacy, safety, and ease of use.

Methadone as a Coanalgesic for Palliative Care Cancer Patients

BACKGROUND

Methadone offers many advantages for treating cancer pain. However, its pharmacokinetic profile makes its use as a full-dose opioid challenging.

OBJECTIVES

To evaluate the efficacy and safety of low-dose methadone as an adjunct to opioids in the treatment of cancer pain in palliative care patients.

DESIGN

A cohort was followed retrospectively for up to 60 days after the initiation of methadone as a coanalgesic.

SETTING/SUBJECTS

Patients were eligible if they were prescribed methadone as a coanalgesic for cancer pain management and followed by the palliative care team.

MEASUREMENTS

The primary efficacy end point was reduction of pain intensity (11-point numerical rating scale). Variables associated with pain intensity reduction were explored using logistic regressions. Adverse events were collected throughout the follow-up.

RESULTS

Seventy-two of the 146 subjects (49%) qualified as significant responders (≥30% reduction in pain intensity). Median time to significant response was seven days, and pain intensity on the day of methadone initiation predicted the response to treatment. The most frequently reported adverse events were drowsiness, confusion, constipation, and nausea. As expected in a palliative care population, there was a substantial amount of missing data.

CONCLUSIONS

A significant reduction in pain can be seen rapidly after the addition of methadone as a coanalgesic, particularly among patients with high pain intensity. More studies are needed to corroborate the efficacy of methadone as an adjunct to opioids.

Efficacy and Safety of Methadone as a Second-Line Opioid for Cancer Pain in an Outpatient Clinic: A Prospective Open-Label Study

INTRODUCTION

Most clinical reports on methadone rotation describe outcomes in hospitalized patients. The few studies that have included outpatients are retrospective. The aim of this study was to assess the efficacy and safety of methadone as a second-line opioid in adult patients with advanced cancer after rotation in routine clinical practice at a palliative care outpatient clinic.

PATIENTS AND METHODS

This was a prospective, open-label study of 145 patients whose treatment was rotated from other opioids to methadone. Informed consent was obtained in all cases. The main outcome measure was change in the variable "worst pain" at day 28. Pain and pain interference were assessed with the Brief Pain Inventory, with side effects evaluated according to the Common Terminology Criteria for Adverse Events version 3.0. Pain levels were evaluated at study entry and at days 3, 7, 9, 14, 21, and 28.

RESULTS

Rotation to methadone was performed for the following reasons: poor pain control (77.9%), opioid side effects (2.1%), or both (20%). The mean daily oral morphine equivalent dose before rotation was 193.7 mg. The median worst and average pain scores decreased significantly (p < .0001) from baseline to day 28: The median worst pain score decreased from 9 (interquartile range [IQR]: 8-10) to 6 (IQR: 3-8), and the median average pain score decreased from 6 (IQR: 5-7) to 4 (IQR: 2-5). The proportions of patients with moderate to severe worst and average pain decreased by 30.3% and 47.5%, respectively, by day 28. No increase in opioid toxicity was observed during the study.

CONCLUSION

In outpatients with advanced cancer, rotation to methadone as a second-line opioid was efficacious and safe when using a tiered scheme with close follow-up by experienced health professionals.

IMPLICATIONS FOR PRACTICE

The results of this study, conducted prospectively under real clinical conditions, support the efficacy and safety of oral methadone as a second-line opioid in ambulatory patients with cancer. Moreover, these findings corroborate previously reported outcomes in retrospective outpatient studies and prospective studies that evaluated inpatient populations. Although more research into methadone rotation strategies is still needed, this study describes a successful tiered scheme of oral methadone rotation that was proven safe and effective during follow-up.

Therapeutic and recreational methadone cardiotoxicity

Several classes of drugs have been associated with an increased risk of cardiovascular disease and occurrence of arrhythmias potentially involved in sudden deaths in chronic users even at therapeutic doses. The study presented herein focuses on pathological changes involving the heart possibly due to methadone use. 60 cases were included in the study in total and were divided into three groups (therapeutic methadone users: 20 cases, recreational methadone users: 20 cases, and sudden death group in subjects who had never taken methadone: 20 cases). Autopsies, histology, biochemistry and toxicology were performed in all cases. Macroscopic and microscopic investigation results in therapeutic methadone users were similar to those observed in sudden, unexpected deaths in non-methadone users. In recreational methadone consumers, macroscopic and microscopic examination of the heart failed to provide results consistent with acute or chronic myocardial or coronary damage, thereby corroborating the hypothesis of death most likely following respiratory depression.

Factors associated with illicit methadone injecting in a Canadian setting

BACKGROUND AND OBJECTIVES

While methadone is well established as an evidence-based treatment for opioid use disorder, safety concerns persist regarding its diversion. The authors examine the prevalence of and risk factors associated with injection of methadone in an urban population.

METHODS

Between December 2005 and November 2013, data were derived from two open prospective studies of persons who inject drugs (PWID) in Vancouver, Canada. Generalized estimating equations (GEE) logistic regression was used to determine factors independently associated with illicit methadone injecting.

RESULTS

During the study, 1911 individuals (34% women) were recruited; 134 (7%) participants reported methadone injecting at least once. In multivariable analysis, Caucasian ethnicity [adjusted odds ratio (AOR) = 1.90, 95% confidence interval (CI) = 1.20-3.00]; homelessness (AOR = 1.46, 95% CI = 1.09-1.95); drug dealing (AOR = 2.10, 95% CI = 1.50-2.93); ≥daily heroin injection (AOR = 1.57, 95% CI = 1.08-2.26); ≥daily crack smoking (AOR = 2.06, 95% CI = 1.44-2.95); being a victim of violence (AOR = 1.48, 95% CI = 1.04-2.12); and non-fatal overdose (AOR = 1.67, 95% CI = 1.67 (1.00-2.79) were independently and positively associated with methadone injection; female gender (AOR = 0.47, 95% CI = 0.30-0.75) was negatively associated.

DISCUSSION AND CONCLUSIONS

The diversion of methadone for illicit injection in this urban setting was associated with several markers of addiction severity and other health and social vulnerabilities.

SCIENTIFIC SIGNIFICANCE

These findings underscore the need to ensure methadone accessibility while limiting diversion-related risk.

Methods of Rotation From Another Strong Opioid to Methadone for the Management of Cancer Pain: A Systematic Review of the Available Evidence

CONTEXT

Up to 44% of patients with cancer-related pain require opioid rotation (OR) because of inadequate analgesia or side effects. No consensus exists regarding the most efficacious method for rotation to methadone.

OBJECTIVES

To define the available evidence regarding methods of rotation to methadone and to determine if sufficient evidence exists regarding the superiority of one method.

METHODS

A predefined search strategy, using Medical Subject Headings (MeSH) search terms and keywords combined using Boolean operators, was performed. Study selection was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. Data were extracted, quality of studies assessed, and narrative synthesis undertaken.

RESULTS

A total of 3214 potentially relevant studies were identified. Twenty-five studies were included: 15 retrospective and 10 prospective (n = 1229). One trial compared three-day switch (3DS) and rapid conversion (RC) methods; two, 3DS; 10, RC; nine, ad libitum (AL). Success rates were as follows: 3DS-93%, RC-71.7%, and AL-92.8%. The single clinical trial and retrospective studies demonstrated poorer analgesia and an excess of adverse events (AEs) in the RC group (five dropouts because of AEs) compared with the 3DS group (no severe AEs). Time to stable analgesia was as follows: RC <4.3 days and AL <6 days.

CONCLUSION

Evidence identified was mainly from uncontrolled observational studies, making causality difficult to establish. Studies were heterogeneous in methodology and outcome measures. There was a trend toward excess AEs using the RC method, in comparison to the AL and 3DS methods. The methodological quality of the AL studies was low. A direct comparison of AL and 3DS methods would be informative.

Out-of-hospital mortality among patients receiving methadone for noncancer pain

IMPORTANCE

Growing methadone use in pain management has raised concerns regarding its safety relative to other long-acting opioids. Methadone hydrochloride may increase the risk for lethal respiratory depression related to accidental overdose and life-threatening ventricular arrhythmias.

OBJECTIVE

To compare the risk of out-of-hospital death in patients receiving methadone for noncancer pain with that in comparable patients receiving sustained-release (SR) morphine sulfate.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted using Tennessee Medicaid records from 1997 through 2009. The cohort included patients receiving morphine SR or methadone who were aged 30 to 74 years, did not have cancer or another life-threatening illness, and were not in a hospital or nursing home. At cohort entry, 32 742 and 6014 patients had filled a prescription for morphine SR or methadone, respectively. The patients' median age was 48 years, 57.9% were female, and comparable proportions had received cardiovascular, psychotropic, and other musculoskeletal medications. Nearly 90% of the patients received the opioid for back pain or other musculoskeletal pain. The median doses prescribed for morphine SR and methadone were 90 mg/d and 40 mg/d, respectively.

MAIN OUTCOMES AND MEASURES

The primary study end point was out-of-hospital mortality, given that opioid-related deaths typically occur outside the hospital.

RESULTS

There were 477 deaths during 28 699 person-years of follow-up (ie, 166 deaths per 10 000 person-years). After control for study covariates, patients receiving methadone had a 46% increased risk of death during the follow-up period, with an adjusted hazard ratio (HR) of 1.46 (95% CI, 1.17-1.83; P < .001), resulting in 72 (95% CI, 27-130) excess deaths per 10 000 person-years of follow-up. Methadone doses of 20 mg/d or less, the lowest dose quartile, were associated with an increased risk of death (HR, 1.59; 95% CI, 1.01-2.51, P = .046) relative to a comparable dose of morphine SR (<60 mg/d).

CONCLUSIONS AND RELEVANCE

The increased risk of death observed for patients receiving methadone in this retrospective cohort study, even for low doses, supports recommendations that it should not be a drug of first choice for noncancer pain.

[Use of methadone in the elderly with cancer pain: a systematic review]

OBJECTIVE

To identify the clinical use of methadone as an analgesic in the management of cancer pain in elderly patients.

MATERIAL AND METHODS

We performed a systemic review of the literature on the specific use of methadone in elderly with cancer pain in MEDLINE, COCHRANE DATABASE and SCOPUS. A second search was conducted in MEDLINE to look for clinical trials and systematic review of the use of methadone in cancer pain, selecting only those in which the mean age of patients was ≥ 65 years old.

RESULTS

Four articles were obtained in the first search, and from the second 7 clinical trials, none of them specific to methadone use in elderly patients with cancer.

CONCLUSIONS

There are insufficient data on the use of methadone as an analgesic in the elderly with cancer. Given its pharmacological characteristics it must be used by trained personnel. Several recommendations are proposed for its use as an analgesic in the treatment of cancer pain in the elderly.

An overview of treatment strategies for cancer pain with a focus on interventional strategies and techniques

SUMMARY As the incidence of cancer increases, considerations for pain treatments become more important and varied. While traditional views on pain therapy are successful in treating the majority of cancer-related pain, a continuum has developed to include interventional strategies in addition to pharmacologic management. Further improvements in understanding anatomy in the context of imaging and pathophysiology of cancer-pain syndromes direct our current interventional pain management options. We discuss the current interventional treatment options regularly used in the cancer-pain population.

Eastern Canadian Colorectal Cancer Consensus Conference: standards of care for the treatment of patients with rectal, pancreatic, and gastrointestinal stromal tumours and pancreatic neuroendocrine tumours

The annual Eastern Canadian Colorectal Cancer Consensus Conference was held in Halifax, Nova Scotia, October 20-22, 2011. Health care professionals involved in the care of patients with colorectal cancer participated in presentation and discussion sessions for the purposes of developing the recommendations presented here. This consensus statement addresses current issues in the management of rectal cancer, including pathology reporting, neoadjuvant systemic and radiation therapy, surgical techniques, and palliative care of rectal cancer patients. Other topics discussed include multidisciplinary cancer conferences, treatment of gastrointestinal stromal tumours and pancreatic neuroendocrine tumours, the use of folfirinox in pancreatic cancer, and treatment of stage ii colon cancer.

Methadone rotation for cancer patients with refractory pain in a palliative care unit: an observational study

BACKGROUND

Methadone has been reported to be as effective as morphine for cancer pain management. It is commonly used as an alternative opioid in case of insufficient relief.

OBJECTIVE

Our aim was to assess efficacy and tolerance of opioid rotation to methadone for refractory cancer pain management in palliative care unit (PCU) inpatients.

METHODS

All the patients undergoing opioid rotation to methadone from 2008 to 2011 in two PCUs (Lyon and Nice, France) were included. Pain assessments were undertaken on day 0 (D0), day 3 (D3), day 7 (D7), and day 14 (D14) using a visual analogue scale (VAS; 0-10) and the Douleur Neuropathique 4 (DN4) scale for neuropathic pain. Patients reported pain relief using a 4-point Likert scale (1=no relief; 4=important relief ).

RESULTS

Nineteen patients (7 females) with a median age of 55 (Q1-Q3; 44-58) underwent methadone rotation. The most common type of cancer was gastrointestinal. Seventeen patients had a diagnosis of mixed pain syndromes. Morphine equivalent daily dose (MEDD) prior to switching was 480 mg (Q1-Q3; 100-1021), and at least two nonmethadone opioid rotations had already been done for 13 patients. Between D0 and D7, the VAS score decreased by 4 points (p<0.001). The DN4 score became negative on D7 for 11 of 17 patients (65%). On D7, 16 of 18 patients (89%) expressed moderate to greater than moderate pain relief. Methadone was discontinued in one patient on D7 because it was deemed ineffective and for 8 patients, who were unable to take oral drugs, it was discontinued after D14.

CONCLUSION

Our results suggest that methadone is effective and well tolerated for refractory cancer pain.

Palliative and end-of-life care in lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

In the United States, lung cancer is a major health problem that is associated with significant patient distress and often limited survival, with some exceptions. The purpose of this article is to address the role of palliative and end-of-life care in the management of patients with lung cancer and to address the need for good communication skills to provide support to patients and families.

METHODS

This article is based on an extensive review of the medical literature up to April 2012, with some articles as recent as August 2012. The authors used the PubMed and Cochrane databases, as well as EBESCO Host search, for articles addressing palliative care, supportive care, lung neoplasm, and quality of life in cancer or neoplasm, with no limitation on dates. The research was limited to human studies and the English language.

RESULTS

There was no "definitive" work in this area, most of it being concurrence based rather than evidence based. Several randomized controlled trials were identified, which are reviewed in the text. The article focuses on the assessment and treatment of suffering in patients with lung cancer, as well as the importance of communication in the care of these patients over the course of the disease. The aim of medical care for patients with terminal lung cancer is to decrease symptom burden, enhance the quality of remaining life, and increase survival benefit. A second objective is to emphasize the importance of good communication skills when addressing the needs of the patient and his or her family, starting at the time of diagnosis, which in itself is a life-changing event. Too often we do it poorly, but by using patient-centered communication skills, the outcome can be more satisfactory. Finally, the article addresses the importance of advance care planning for patients with lung cancer, from the time of diagnosis until the last phase of the illness, and it is designed to enhance the physician's role in facilitating this planning process.

CONCLUSIONS

This article provides guidance on how to reduce patient distress and avoid nonbeneficial treatment in patients with lung cancer. The goal is to decrease symptom burden, enhance quality of life, and increase survival benefit. Good communication and advance care planning are vital to the process.

Epidural methadone results in dose-dependent analgesia in cancer pain, further enhanced by epidural dexamethasone

Background:

This study was designed to evaluate the role of epidural methadone-lidocaine in cancer pain combined or not to epidural dexamethasone.

Methods:

In all, 72 cancer patients, 32- to 67-year-old were randomized to six groups (n=12) and prospectively studied to examine analgesia and adverse effects for 3 weeks. Patients received single-dose protocol epidural test drugs: Control group (CG) received epidural 40-mg lidocaine diluted to 10-ml volume with saline. Dexamethasone group (DG) 40-mg lidocaine plus 10-mg dexamethasone. The 2.5MetG 2.5-mg epidural methadone with 40-mg lidocaine; the 5MetG, 5-mg epidural methadone plus 40-mg lidocaine, the 7.5MetG, 7.5-mg epidural methadone plus 40-mg lidocaine and finally the 7.5Met-DexG, 7.5-mg methadone with 40-mg lidocaine and 10-mg dexamethasone.

Results:

Groups CG, DG and 2.5MetG were similar regarding analgesia and side effects. Patients from 5MetG and 7.5MetG took 3±1 and 5±1 days, respectively, to restart oral morphine. Patients from 7.5MetDG took 14±2 to restart oral morphine (P<0.001). Daily somnolence and appetite improved in the 7.5MetDG during 2-week evaluation (P<0.005). Fatigue improved for both DG and 7.5MetDG during 2-week evaluation (P<0.005). By the third week of evaluation, all patients were similar.

Conclusions:

Epidural methadone plus lidocaine resulted in dose-dependent analgesia, further improved by epidural dexamethasone, which also improved fatigue.

Mechanism-based inactivation of cytochrome P450 2B6 by methadone through destruction of prosthetic heme

Methadone is a μ-opioid receptor agonist widely used in the treatment of narcotic addiction and chronic pain conditions. Methadone is metabolized predominantly in the liver by cytochromes P450 to its pharmacologically inactive primary metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine. Initial in vitro data suggested that CYP3A4 is the major isoform responsible for the in vivo clearance of methadone in humans. However, recent clinical data have indicated that CYP2B6 is actually the major isoform responsible for methadone metabolism and clearance in vivo. In this study, methadone was shown to act as a mechanism-based inactivator of CYP2B6. Methadone inactivates CYP2B6 in a time-, concentration-, and NADPH-dependent manner with a K(I) = 10.0 μM and k(inact) = 0.027 min⁻¹. The loss of CYP2B6 activity in the presence of methadone and NADPH occurred with concomitant loss of the reduced CO spectrum of the P450. Moreover, there was good correlation between the loss of CYP2B6 activity and the loss of the CO-binding spectrum. High-performance liquid chromatography analysis of the native heme of the inactivated CYP2B6 demonstrated that approximately 75% loss of heme was accompanied by comparable inactivation of CYP2B6. Liquid chromatography-mass spectrometry analysis did not reveal the formation of a protein adduct during the inactivation. The evidence strongly suggests that destruction of prosthetic heme is the underlying mechanism leading to the inactivation of CYP2B6 by methadone.

Management of Severe Neuropathic Cancer Pain

Neuropathic cancer pain is common, very disabling and difficult to treat. It can be related to tumor invasion of neural structures and neuronal damage by surgery, chemotherapy and radiation therapy. Adjuvant analgesics are often used with opioids to control neuropathic pain in cancer patients. Methadone, a synthetic opioid with multiple mechanisms of action, is gaining increasing importance as an effective agent in the treatment of cancer related neuropathic pain. This case illustrates the challenges of managing severe pain in a patient with head and neck cancer while undergoing anti-tumor treatment. A review of the adjuvant analgesics and opioids, particularly methadone, in the management of neuropathic pain is also included.

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.

Pain management in patients with cancer: focus on opioid analgesics

Cancer pain is generally treated with pharmacological measures, relying on using opioids alone or in combination with adjuvant analgesics. Weak opioids are used for mild-to-moderate pain as monotherapy or in a combination with nonopioids. For patients with moderate-to-severe pain, strong opioids are recommended as initial therapy rather than beginning treatment with weak opioids. Adjunctive therapy plays an important role in the treatment of cancer pain not fully responsive to opioids administered alone (ie, neuropathic, bone, and visceral colicky pain). Supportive drugs should be used wisely to prevent and treat opioids’ adverse effects. Understanding the pharmacokinetics, pharmacodynamics, interactions, and cautions with commonly used opioids can help determine appropriate opioid selection for individual cancer patients.

Effects of the delta-opioid agonist SNC80 on the abuse liability of methadone in rhesus monkeys: a behavioral economic analysis

RATIONALE

Delta-opioid agonists enhance the antinociceptive efficacy of methadone and other mu-opioid agonists. However, relatively little is known about the degree to which delta agonists might enhance the abuse-related effects of mu agonists.

OBJECTIVE

This study used a behavioral economic approach to examine effects of the delta agonist SNC80 [(+)-4-[(αR)-α-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide] on the reinforcing effects of methadone in a drug self-administration assay. Interactions between SNC80 and cocaine were also examined for comparison.

METHODS

Rhesus monkeys (n = 4), surgically implanted with indwelling intravenous catheters, were tested in two phases. In phase 1, drug self-administration dose-effect curves for methadone (0.0032-0.1 mg/kg/injection (inj)) and cocaine (0.0032-0.32 mg/kg/inj) alone were determined under a fixed-ratio 10 (FR 10) schedule of reinforcement. In phase 2, FR values were increased every 3 days (FR 1-FR 1800) during availability of methadone alone (0.032 mg/kg/inj) and in combination with varying proportions of SNC80 (0.1:1, 0.3:1, and 0.9:1 SNC80/methadone) or of cocaine alone (0.032 mg/kg/inj) and in combination with varying proportions of SNC80 (0.33:1, 1:1, and 3:1 SNC80/cocaine). Demand curves related drug intake to FR price, and measures of reinforcement were derived.

RESULTS

Methadone and cocaine alone each functioned as a reinforcer. SNC80 did not alter measures of reinforcement for either methadone or cocaine.

CONCLUSIONS

SNC80 at proportions previously shown to enhance methadone-induced antinociception did not enhance the abuse-related effects of methadone. These results support the proposition that delta agonists may selectively enhance mu agonist analgesic effects without enhancing mu agonist abuse liability.

An unusual case of accidental poisoning: fatal methadone inhalation

In this report, the authors present a case of unusual, accidental methadone intoxication in a 40-year-old man, who had inhaled methadone powder. The drug dealer was a pharmacy technician; methadone had been stolen from a pharmacy and sold as cocaine. After having inhaled methadone powder, he suffered cardiopulmonary arrest. He was admitted to hospital where he died after 24 h of intensive care. The autopsy revealed congestion of internal organs and cerebral and pulmonary edema. Microscopically, the heart showed no changes. The toxicological analyses performed on blood and urine taken at the hospital revealed methadone, cannabinoids, and ethanol. The blood methadone concentration was 290 μg/L. The urine methadone concentration was 160 μg/L. Midazolam and lidocaine, which were administered to the patient at the hospital, were also detected in the blood. The cause of death was determined to be methadone intoxication. The literature has been reviewed and discussed. To date, and to our knowledge, only very few cases of accidental death resulting from methadone inhalation have been described up to the case presented herein.