How to switch from morphine or oxycodone to methadone in cancer patients? a randomised clinical phase II trial

Methadone Conversion Using a 3-Day Switch Strategy in Patients with Cancer on High-Dose Opioids: A Retrospective Study

INTRODUCTION

Methadone has shown effectiveness in pain control in patients with cancer who are intolerant to other opioids in China. However, the optimal strategy for methadone conversion from previous high doses of opioids in refractory cancer pain remains debatable. This study aimed to describe the efficacy and safety of a 3-day switch (3DS) strategy for methadone conversion in patients with refractory cancer pain on high doses of opioids.

METHODS

We retrospectively reviewed 30-day medical records of 70 patients with refractory cancer pain who used a 3DS strategy for methadone conversion from previous high doses of opioids from July 2018 to December 2022. The 3DS strategy indicated that the methadone dose was increased by one third every day for 3 days. Data on the rate of successful conversion, the time to stable analgesia after conversion, the conversion efficiency, the corrected QT (QTc) interval, the actual conversion ratios, adverse events (AEs), and quality of life were analyzed.

RESULTS

Seventy patients received 3DS methadone conversion and 64 patients were eligible for analysis. Fifty patients (78%) achieved stable analgesia, and the median time to stable analgesia was 8.14 ± 2.70 (range 6-14) days. The average dose of methadone was 77.94 ± 42.74 mg. The most common AEs (≥ 10%) included constipation, dry mouth, nausea, and cold sweats. The incidence of constipation was reduced post-methadone conversion, and a statistically significant but asymptomatic prolongation of the QTc interval was observed. Additionally, the actual conversion ratios were lower than Ayonrinde's recommended ratios.

CONCLUSIONS

The 3DS strategy for methadone conversion is applicable in Chinese patients with refractory cancer pain on high doses of opioids.

Comparison of a novel methadone rotation method with other commonly used methods

OBJECTIVES

To compare a novel method of methadone rotation used in a specialist palliative care inpatient unit (SPCU) in Cork, Ireland, with rapid titration methods using Perth and Brisbane Protocols as well as the Edmonton method of methadone rotation.

METHODS

A retrospective chart review was performed in March-June 2022. All patients who completed rotation to methadone during 2018-2019 in the SPCU were included. 2018-2019 was selected to study a population not affected by the coronavirus pandemic. Oral morphine equivalent (OME) was calculated using the opioid conversion chart. From the OME, the expected daily methadone dose was calculated using the Perth, Brisbane and Edmonton methods. These figures were then compared directly with the actual methadone doses achieved using our dosing schedule.

RESULTS

A comparison of the expected doses using the Perth and Brisbane rapid titration protocols and stable daily dose achieved revealed that the stable methadone dose was significantly lower than both rapid titration protocols (p=<0.0001) and (p=0.0035, respectively). However, a comparison of the expected dose using the Edmonton method and the dose achieved did not determine any significant difference (p=0.7602).

CONCLUSIONS

This is the first evaluation of a novel Irish method of methadone rotation and demonstrates a lower overall daily methadone dose compared with established protocols.

Opioid analgesic dose and route conversion ratio studies: a scoping review to inform an eDelphi guideline

BACKGROUND

Clinicians regularly prescribe opioids to manage acute and chronic cancer pain, frequently to address acute postoperative pain, and occasionally to manage chronic non-cancer pain. Clinical efficacy may be suboptimal in some patients due to side effects and/or poor response, and opioid rotation/switching (conversions) is frequently necessary. Despite the widespread practice, opioid conversion ratios are inconsistent between clinicians, practices, and countries. Therefore, we performed a scoping systematic review of opioid conversion studies to inform an international eDelphi guideline.

METHODS

To ensure a comprehensive review, we conducted a systematic search across multiple databases (OVID Medline, PsycINFO, Embase, EBM-Cochrane Database of Systematic Reviews and Registered Trials, LILACS, IMEMR, AIM, WPRIM) using studies published up to June 2022. Additionally, we performed hand and Google Scholar searches to verify the completeness of our findings. Our inclusion criteria encompassed randomized and non-randomized studies with no age limit, with only a few pediatric studies identified. We included studies on cancer, non-cancer, acute, and chronic pain. The level and grade of evidence were determined based on the Multinational Supportive Care in Cancer (MASCC) criteria.

RESULTS

Our search yielded 21,118 abstracts, including 140 randomized (RCT) and 68 non-randomized (NRCT) clinical trials. We compared these results with recently published conversion ratios. Modest correlations were noted between published reviews and the present scoping systematic review.

CONCLUSION

The present scoping systematic review found low-quality evidence to support an opioid conversion guideline. We will use these data, including conversion ratios and type and route of administration, to inform an eDelphi guideline.

A better interpretation of data regarding the opioid switching to methadone

In a recent study methadone has been reported more effective witha 3-day switch (3DS) was more effective than the stop and go strategy (SAG). Many shorcomings, however, are of concerns. The poor selection fo patients with low level of pain intensity, the incomprehensibile choice of of SAG or 3DS, and considerations reported in a previous controlled study with evident methodological limits, make their conclusion inaccurate. Controlled studies are fundamental in research. However, a pragmatic approach reflecting daily practice should be carefully taken into consideration. A more flexible use of SAG strategy and strict clinical observation to change doses according to the clinical response may provide the optimal treatment in patients receiving high doses of opioids.

Reply to "A better interpretation of data regarding the opioid switching to methadone"

In our article ?Methadone switching for refractory cancer pain' (BMC palliative care, 2022) we explore the efficacy, safety and economics of methadone in treatment of patients with refractory cancer pain in China. Professor Mercadante provided a better interpretation of data regarding the opioid switching to methadone in the Matters Arising. In this article, we answered the questions in Mercadante et al.'s comments one by one.

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.

Cancer Pain Treatment Strategies in Patients with Cancer

Management of cancer pain is challenging. Despite the poor evidence, opioid therapy still remains the cornerstone for the management of cancer-related pain. Opioids should be given according to the clinical presentation in the different stages of disease. There is no drug of choice, as most opioids are effective. Thus, the choice should be based on the individual characteristics of patients. Optimization of opioid therapy may allow individual treatment according to the patient's characteristics and pain syndromes, providing timely alternatives in the different stages of disease. While most patients respond to an appropriate treatment associated with a comprehensive assessment and symptom control, a high level of experience and knowledge is necessary in determining conditions to maximize the analgesic response, eventually adding adjuvants in some specific circumstances. Alternative opioids may improve the balance between analgesia and adverse effects in the presence of a poor response to the first opioid in a large number of patients. Finally, a selected population can benefit from some interventional procedures.

Oral Morphine as an Alternative Substitution Treatment for Opioid Use Disorder, a Rare but Non-risk-free Use

Background

National health monitoring agencies have reported the alternative use of morphine sulfate painkiller for maintenance treatment of opioid use disorder (OUD), associated with a potential increase in overdose risk.

Objectives

This study sought to assess the prevalence of regular and occasional legally prescribed morphine use in patients treated for OUD and compare their characteristics to those of patients receiving conventional opioid maintenance treatment (OMT), buprenorphine or methadone. Then, we assessed the factors associated with opioid overdose risk.

Methods

Data were extracted from the French national healthcare system database, covering the entire population in 2015. Diagnosis associated with hospital discharge and long-term disease codes were extracted to select the population and identify outcomes and covariates. OUD non-chronic pain patients were divided into regular (≤35 days between dispensing and ≥3 months of continuous treatment duration) morphine users, and occasional users. Their sociodemographic and health characteristics were compared to OMT controls. A multivariate logistic regression model was performed to determine factors associated with opioid overdose.

Results

In patients treated for OUD, 2,237 (2.2%) morphine users (1,288 regular and 949 occasional), 64,578 (63.7%) buprenorphine and 34,638 (34.1%) methadone controls were included. The prevalence of regular morphine use among patients treated for OUD regularly receiving an opioid was 1.3%. Compared to users who receive morphine regularly, occasional users had an increased risk of overdose [OR = 2.2 (1.5-3.3)], while the risk was reduced in the buprenorphine group [OR = 0.5 (0.4-0.7)] and not significantly different for methadone [OR = 1.0 (0.7-1.4)]. Other overdose risk factors were low-income, comorbidity, i.e., psychiatric conditions, alcohol use disorder or complications related to intravenous drug use, and coprescription with benzodiazepines or pregabalin. These factors were more frequent in morphine groups.

Conclusions

Patients that were prescribed oral morphine represented a small minority of the treated for OUD. The poorer health condition affected by numerous comorbidities and higher risk of opioid overdose in patients treated with oral morphine compared with OMT controls points toward the need to better supervise the practices of these patients, to strengthen multidisciplinary care and risk reduction measures.

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.

Revision of Pharmacological Treatment Recommendations for Cancer Pain: Clinical Guidelines from the Japanese Society of Palliative Medicine

Background: Pain is one of the most common symptoms in cancer patients. The Japanese Society for Palliative Medicine (JSPM) first published its clinical guidelines for the management of cancer pain in 2010. Since then, more research on cancer pain management has been reported, and new drugs have become available in Japan. Thus, the JSPM has now revised the clinical guidelines using a validated methodology. Methods: This guideline was developed through a systematic review, discussion, and the Delphi method, following a formal guideline development process. Results: Thirty-five recommendations were created: 19 for the pharmacological management of cancer pain, 6 for the management of opioid-induced adverse effects, and 10 for pharmacological treatment procedures. Due to the lack of evidence that directly addressed our clinical questions, most of the recommendations had to be based on consensus among committee members and other guidelines. Discussion: It is critical to continue to build high-quality evidence in cancer pain management, and revise these guidelines accordingly.

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.

Assistance of a Palliative Care Certified Nurse in the Alleviation of Refractory Cancer Pain by Switching Opioids to Oral Methadone in a Japanese Outpatient Setting

Although methadone has the potential to improve the management of cancer pain, it has some serious problems, such as respiratory depression and QT interval prolongation. Therefore, patients who are prescribed methadone must be educated, monitored, and supported by specialized medical staff, especially in the outpatient setting. We assessed the effectiveness of support from the palliative care certified nurse who used the checklists in opioid switching to oral methadone for patients with refractory pain. Through the multidisciplinary palliative care team at our hospital, 15 outpatients with cancer pain were prescribed oral methadone between April 2013 and December 2020, and 14 cases were successful in switching to methadone. After taking medication, the certified nurse called the patient's home daily for 3 to 5 days and confirmed that the patient had taken the methadone, the degree of pain, the number of rescue medications, and the appearance of side effects, such as respiratory depression. Careful management by a multidisciplinary team is essential for opioid switching to oral methadone administration for outpatients. Certified nurses may play an important role in maintaining safety and resolving the patients' and families' anxieties with respect to the prescription of methadone.

Switching Ratio from Parenteral to Oral Methadone 1:1.2 Is Safer Compared with Ratio 1:2 in Patients with Controlled Cancer Pain: A Multicenter Randomized-Controlled Trial (RATIOMTD-010810)

Background: The most commonly used switching ratio from parenteral to oral methadone is 1:2. Methadone is highly bioavailable and a lower ratio might result in similar analgesia with less toxicity. Objective: To compare success and side effects with two ratios from parenteral to oral methadone: 1:2 versus 1:1.2 in hospitalized patients with cancer pain. Design: A multicenter double-blind randomized clinical trial. Settings/Particiants: Inpatients with well-controlled cancer pain with parenteral methadone requiring rotation to the oral route. Measurements: Outcomes included pain intensity (Brief Inventory Pain), opioid toxicity (Common Toxicology Criteria for Adverse Events), and methadone dose. Success was defined as no toxicity with good pain control at 72 hours. Results: Thirty-nine of forty-four randomized patients were evaluable: 21 in ratio 1:2 and 18 in ratio 1:1.2. Seventy-one percent male. Median age 65 years. No significant differences in basal clinical characteristics between both groups. Median methadone dose pre/post switching was 24.5 mg ±13.5 and 49 mg ±27.3 for ratio 1:2, versus 23.3 mg ±9.4 (p: not significant) and 28 mg ±11.3 (p < 0.01) for ratio 1:1.2. Pain was well controlled without differences between both ratios. Drowsiness at day +1 (p < 0.017) and myoclonus at day +3 (p < 0.019) were more prevalent in group 1:2. Success was observed in 12 patients in ratio 1:2 versus 18 in ratio 1:1.2 (p < 0.001). Methadone side effects were observed in 12 patients in ratio 1:2 (mainly neurotoxicity symptoms) versus 2 in ratio 1:1.2 (p < 0.005). Conclusion: Ratio 1:1.2 when changing from parenteral to oral methadone resulted in lower toxicity and no difference in analgesia. More conservative dose adjustment during methadone route change should be considered. European Clinical Trials Register (EudraCT No. 2010-024092-39).

How to Use Methadone in an Era of an Opioid Epidemic

OPINION STATEMENT

The opioid epidemic is one of the most important public health crises as opioid-related deaths have become a leading cause of accidental death in the USA. Various efforts have been made to understand how to safely and appropriately prescribe opioids for patients with chronic pain, including those with cancer-related pain. We find the guidelines proposed by the Expert Consensus White Paper on the use of methadone to be current, comprehensive, and practical. While methadone is a complex medication with unique pharmacokinetics and pharmacodynamics, it remains a superior choice for many patients with cancer pain given its cost and applicability in a variety of situations. Methadone should be prescribed in the context of experienced clinicians as well as an interdisciplinary team. At a critical time when preventing opioid-related deaths is a priority, we recommend implementing additional precautions for monitoring including universal screening for risk of non-medical opioid use, education on proper storage and disposal, as well as discussing a plan with patients and caregivers in the case of serious complications such as opioid overdose.

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.

Comparing Methadone Rotation to Consensus Opinion

CONTEXT

Methadone is a complex but useful medication for pain management in palliative care. Recent expert opinions have been published on the safe and effective use of methadone.

OBJECTIVES

To determine the success of methadone rotations and evaluate concordance with consensus recommendations by a palliative care consult service.

METHODS

A retrospective study of methadone rotation practice by a palliative care consult service and outcomes for patients hospitalized between January 1, 2012 and December 31, 2018 at a single academic medical center. A successful rotation was defined as a 30% reduction in pain or as-needed medication use sustained for at least three consecutive days. Patient outcomes were compared with expert consensus recommendations.

RESULTS

About 59 patients met the inclusion criteria. The study population was mostly Caucasian men and women of equal proportions who were started on methadone for inadequate pain control. Sixty-eight percent of patients were successfully rotated. Subjects who were rotated using a standardized protocol were six times more likely to have a successful rotation (odds ratio 6.28 [1.25-30.92]; P = 0.0238).

CONCLUSION

The utilization of a standardized protocol was associated with better patient outcomes.

Conversion of other opioids to methadone: a retrospective comparison of two methods

CONTEXT

A rapid method of methadone conversion known as the Perth Protocol is commonly used in Australian palliative care units. There has been no follow-up or validation of this method and no comparison between different methods of conversion.

OBJECTIVES

The primary objective of this study was to test the hypothesis that the achieved doses of methadone are independent of the conversion method (rapid vs slower). The secondary objectives included examining the relationship between calculated target doses, actual achieved doses and duration of conversions.

METHODS

This is a retrospective chart audit conducted at two hospital sites in the Brisbane metropolitan area of Australia which used different methadone conversion methods.

RESULTS

Methadone conversion ratios depended on previous opioid exposure and on the method of conversion used. The method most commonly used in Australia for calculating target doses for methadone when converting from strong opioids is a poor predictor of actual dose achieved. More appropriate conversion ratios are suggested.

CONCLUSION

Further research is needed to refine the ratios used in practice when converting patients from strong opioids to methadone. Caution and clinical expertise are required. A palliative methadone registry may provide useful insights.

A Comparative Study of Opioid Switching to Methadone for Cancer Pain Control in Successful and Unsuccessful Cases

Background: Methadone may play a role in the control of refractory cancer pain in opioid switching, although some cases fail to switch to methadone. Objective: To evaluate the differences in the clinical aspects in switching to methadone between successful cases (SCs) and unsuccessful cases (UCs). Design: This was a retrospective study of the clinical aspects of cancer patients who experienced opioid switching from other opioids to methadone. Setting/Subjects: Eighty-seven patients who were prescribed oral methadone in our hospital were analyzed. Methadone was initiated from other opioids due to refractory pain in the stop-and-go switching. Among the 87 cases, 7 cases were excluded from further analysis because methadone administration was stopped due to vomiting or self-cessation within six days from switching. Results: Among the 80 cases who had methadone for seven days or more, 70 cases (SCs) were successful in switching to methadone, according to the Japanese definition, although 10 cases (UCs) who experienced the rapid progression of illness failed due to oral difficulty in the course of titration. In comparison of the clinical characteristics between SCs and UCs, the number of days alive from the start of the administration of methadone was significantly greater in the SCs than in the UCs (SCs: 87.1, UCs: 19, p < 0.0001), but no significant differences were observed for any other factors. Conclusion: From this comparative retrospective study of opioid switching to methadone for cancer pain control between SCs and UCs, early switching to methadone may be useful for patients with advanced cancer pain.

[Opioid switch and change of route of administration in cancer patients treated by morphine]

This paper reviewed the 2002 guidelines established by the National Federation of Cancer Centres. A group of experts nominated by the 3 French Societies involved in the treatment of cancer pain (AFSOS, SFAP, SFETD), established new guidelines ratios for morphine switching and/or changing of route of administration, in patients for whom either pain was not adequatly managed or adverse effects were unbearable. After a rapid reminder of the pharmacokinetics and metabolism properties of morphine, experts explained why the theory of opioid rotation (oxycodone, hydromorphone, fentanyl, methadone, tapentadol) using fixed equianalgesic ratios is not any more appropriate for a secure clinical practice. In the light of recent publications enhancing our knowledge on the efficacy of new drug switching ratios and for changing the route of administration of morphine, the group of experts recommended to use reconsidered switching ratios favoring security upon efficacy, to minimize overdosing and adverse effects. Consequently, after the new conversion ratio (using slow release opioids) was applied, a second titration should be done by means of normal release rescue formulations for breakthrough pain episodes. A smartphone App. OpioConvert^® will be available for rapid and secure dose conversions.

Opioid Rotation in Cancer Pain Treatment

BACKGROUND

Rotating several different WHO level III opioid drugs is a therapeutic option for patients with chronic cancer-related pain who suffer from inadequate analgesia and/or intolerable side effects. The evidence favoring opioid rotation is controversial, and the current guidelines in Germany and other countries contain only weak recommendations for it.

METHODS

This review is based on pertinent publications retrieved by a systematic review of the literature on opioid rotation for adult patients with chronic cancerrelated pain who are regularly taking WHO level III opioids by the oral or trans - dermal route.

RESULTS

9 individual studies involving a total of 725 patients were included in the analysis, and 3 previous systematic reviews of studies involving a total of 2296 patients were also analyzed. Morphine, oxycodone, fentanyl, hydromorphone, and buprenorphine were used as first-line opioid drugs, and hydromorphone, bupre - norphine, tapentadol, fentanyl, morphine, oxymorphone, and methadone were used as second-line opioid drugs. In all of the studies, pain control was achieved for 14 days after each rotation. In most of them, the dose of the new drug introduced in each rotation needed to be increased above the dose initially calculated from a rotation ratio, with the exception of rotations to methadone. The frequency of side effects was only rarely lessened, but patients largely considered the result of opioid rotation to be positive. No particular opioid drug was found to be best.

CONCLUSION

Opioid rotation can improve analgesia and patient satisfaction. The success of opioid rotation appears to depend on the magnitude of the initial dose, among other factors. Tables of equianalgesic doses should be considered no more than a rough guide for determining the dose of the new drug. Rotations to methadone should be carried out under clinical supervision in experienced hands.

Methadone versus Fentanyl in Patients with Radiation-Induced Nociceptive Pain with Head and Neck Cancer: A Randomized Controlled Noninferiority Trial

BACKGROUND

Pain is still a burden for many patients with cancer. A recent trial showed the superiority of methadone over fentanyl in neuropathic pain, and we expect that this finding could influence the number of patients treated with methadone.

METHODS

We performed a randomized controlled noninferiority trial in patients with nociceptive pain. Eighty-two strong-opioid-naïve patients with head and neck cancer with substantial pain (pain numeric rating scale [NRS] score ≥ 4) due to radiation therapy were included. Forty-two patients were treated with methadone, and 40 with fentanyl. Patients were evaluated at 1, 3, and 5 weeks. The primary outcomes were reduction in average pain and clinical success (50% pain decrease). We set the predefined noninferiority margin at 1 on the NRS and 10% clinical success. Secondary outcomes were pain interference, global perceived effect (GPE), side effects, and opioid escalation index.

RESULTS

Noninferiority was shown for decrease in NRS for maximum and mean pain scores at 1 and 3 weeks. Noninferiority was shown for clinical success at 1 week only. The opioid escalation index was lower in the methadone group at 3 and 5 weeks as compared to fentanyl (1.44 vs. 1.99, P = 0.004; and 1.50 vs. 2.32, P = 0.013). The pain interference in the methadone group was significantly decreased at 3 weeks only. GPE and side effects were not different.

CONCLUSION

This is the first study to show noninferiority of methadone compared to fentanyl at 1 and 3 weeks in the treatment of radiation-induced nociceptive pain in patients with head and neck cancer.

Methadone for cancer pain

BACKGROUND

This is an updated review originally published in 2004 and first updated in 2007. This version includes substantial changes to bring it in line with current methodological requirements. Methadone is a synthetic opioid that presents some challenges in dose titration and is recognised to cause potentially fatal arrhythmias in some patients. It does have a place in therapy for people who cannot tolerate other opioids but should be initiated only by experienced practitioners. This review is one of a suite of reviews on opioids for cancer pain.

OBJECTIVES

To determine the effectiveness and tolerability of methadone as an analgesic in adults and children with cancer pain.

SEARCH METHODS

For this update we searched CENTRAL, MEDLINE, Embase, CINAHL, and clinicaltrials.gov, to May 2016, without language restriction. We also checked reference lists in relevant articles.

SELECTION CRITERIA

We sought randomised controlled trials comparing methadone (any formulation and by any route) with active or placebo comparators in people with cancer pain.

DATA COLLECTION AND ANALYSIS

All authors agreed on studies for inclusion. We retrieved full texts whenever there was any uncertainty about eligibility. One review author extracted data, which were checked by another review author. There were insufficient comparable data for meta-analysis. We extracted information on the effect of methadone on pain intensity or pain relief, the number or proportion of participants with 'no worse than mild pain'. We looked for data on withdrawal and adverse events. We looked specifically for information about adverse events relating to appetite, thirst, and somnolence. We assessed the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

We revisited decisions made in the earlier version of this review and excluded five studies that were previously included. We identified one new study for this update. This review includes six studies with 388 participants. We did not identify any studies in children.The included studies differed so much in their methods and comparisons that no synthesis of results was feasible. Only one study (103 participants) specifically reported the number of participants with a given level of pain relief, in this case a reduction of at least 20% - similar in both the methadone and morphine groups. Using an outcome of 'no worse than mild pain', methadone was similar to morphine in effectiveness, and most participants who could tolerate methadone achieved 'no worse than mild pain'. Adverse event withdrawals with methadone were uncommon (12/202) and similar in other groups. Deaths were uncommon except in one study where the majority of participants died, irrespective of treatment group. For specific adverse events, somnolence was more common with methadone than with morphine, while dry mouth was more common with morphine than with methadone. None of the studies reported effects on appetite.We judged the quality of evidence to be low, downgraded due to risk of bias and sparse data. For specific adverse events, we considered the quality of evidence to be very low, downgraded due to risk of bias, sparse data, and indirectness, as surrogates for appetite, thirst and somnolence were used.There were no data on the use of methadone in children.

AUTHORS' CONCLUSIONS

Based on low-quality evidence, methadone is a drug that has similar analgesic benefits to morphine and has a role in the management of cancer pain in adults. Other opioids such as morphine and fentanyl are easier to manage but may be more expensive than methadone in many economies.

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.

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.

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.

Methadone for Patients with Malignant Psoas Syndrome: Case Series of Three Patients

BACKGROUND

Malignant psoas syndrome (MPS) is a relatively rare syndrome that accompanies malignancy; the pain associated with MPS is often difficult to control. Methadone is known to be effective in relieving both nociceptive and neuropathic pain.

OBJECTIVE

Herein we describe treatment strategies for three patients with MPS, diagnosed by imaging and clinical findings, who responded to methadone treatment.

METHODS

Patient diagnoses, pain characteristics, and treatment were analyzed retrospectively. Subjects were three patients with MPS who presented to Hyogo Cancer Center with pain. A numeric rating scale (NRS; 0-10) was used to assess patients' pain levels.

RESULTS

All three patients were diagnosed with malignancies (prostate, cervical, and urachal) and had impaired gait and thigh extension. All had tumor invasion to the iliopsoas muscle, as determined by imaging, and were diagnosed with MPS. After starting methadone, symptoms improved in all patients and they were able to extend the thigh and walk normally. The NRS scores improved by an average of -7.3 points (95% confidence interval [CI] -4.97, -9.69) on Day 14; and the average time until symptom improvement after starting methadone was 2.3 days (95% CI 1.86, 2.80).

CONCLUSIONS

Methadone may be considered a treatment choice for MPS patients in whom pain is difficult to control.

Morphine or oxycodone for cancer-related pain? A randomized, open-label, controlled trial

CONTEXT

There is wide interindividual variation in response to morphine for cancer-related pain; 30% of patients do not have a good therapeutic outcome. Alternative opioids such as oxycodone are increasingly being used, and opioid switching has become common clinical practice.

OBJECTIVES

To compare clinical response to oral morphine vs. oral oxycodone when used as first-line or second-line (after switching) treatment in patients with cancer-related pain.

METHODS

In this prospective, open-label, randomized, controlled trial (ISRCTN65155201) with a selected crossover phase, patients with cancer-related pain were randomized to receive either oral morphine or oxycodone as first-line treatment. Dose was individually titrated until the patient reported adequate pain control. Patients who did not respond to the first-line opioid (either because of inadequate analgesia or unacceptable adverse effects) were switched to the alternative opioid.

RESULTS

Two hundred patients were recruited. On intention-to-treat analysis (n = 198, morphine 98, oxycodone 100), there was no significant difference between the numbers of patients responding to morphine (61/98 = 62%) or oxycodone (67/100 = 67%) when used as a first-line opioid. Similarly, there was no significant difference in subsequent response when patients were switched to either morphine (8/12 = 67%) or oxycodone (11/21 = 52%). Per-protocol analysis demonstrated a 95% response rate when both opioids were available. There was no difference in adverse reaction scores between morphine and oxycodone either in first-line responders or nonresponders.

CONCLUSION

In this population, there was no difference between analgesic response or adverse reactions to oral morphine and oxycodone when used as a first- or second-line opioid. These data provide evidence to support opioid switching to improve outcomes.

[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.

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.

Endogenous opiates and behavior: 2011

This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).

Serum concentrations of opioids when comparing two switching strategies to methadone for cancer pain

PURPOSE

Our aim was to compare pharmacological aspects of two switching strategies from morphine/oxycodone to methadone; the stop and go (SAG) strategy in which methadone is started directly after the initial opioid has been stopped, and the 3-days switch (3DS), in which morphine/oxycodone is gradually changed to methadone by cross-tapering over 3 days.

METHODS

Forty-two cancer patients with pain and/or opioid side effects were assessed in this randomised trial. Trough serum concentrations of methadone, morphine, morphine-6-glucuronide (M6G), and oxycodone were measured on days 1, 2, 3, 4, 7, and 14. Primary outcome was number of patients with methadone concentrations in apparent C(SS) on day 4. Secondary outcomes were exposure to opioids during the first 3 days, interindividual variation of opioid concentrations, and correlation between methadone concentrations and pain intensity (PI) day 3.

RESULTS

Thirty-five patients received methadone (16 in the SAG group, 19 in the 3DS group). The median preswitch morphine equivalent doses were 620 (range 350-2000) mg/day in the SAG group and 800 (range 90-3600) mg/day in the 3DS group (p = 0.43);42% reached C(SS) for methadone in the SAG group on day 4 compared with 22% in the 3DS group (p = 0.42). The SAG group was significantly less exposed to morphine/M6G/oxycodone and significantly more exposed to methadone in the first 3 days. Methadone showed a low correlation with PI. More patients dropped out after intervention in the SAG group than in the 3DS group (38% vs. 5%; p = 0.032). One SAG patient suffered from respiratory depression on day 5.

CONCLUSION

The SAG group was initially more exposed to methadone and less to the replaced opioids but without observed clinical benefit and with a higher dropout rate. Patients switched to methadone should be followed closely for the first 5 days, regardless of switching strategy.