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

Conversion ratios for opioid switching: a pragmatic study

BACKGROUND

The final conversion ratios among opioids used for successful switching are unknown. The aim of this study was to determine the initial and final conversion ratios used for a successful opioid switching in cancer patients, and eventual associated factors.

METHODS

Ninety-five patients who were successfully switched were evaluated. The following data were collected: age, gender, Karnofsky performance score, primary cancer, cognitive function, the presence of neuropathic, and incident pain. Opioids, route of administration, and their doses expressed in oral morphine equivalents used before OS were recorded as well as opioids use for starting opioid switching, and at time of stabilization. Physical and psychological symptoms were routinely evaluated by Edmonton Symptom Assessment Scale.

RESULTS

No statistical changes were observed between the initial conversion ratios and those achieved at time of stabilization for all the sequences of opioid switching. When considering patients switched to methadone, there was no association between factors taken into considerations.

CONCLUSION

Opioid switching is a highly effective and safe technique, improving analgesia and reducing the opioid-related symptom burden. The final conversion ratios were not different from those used for starting opioid switching. Patients receiving higher doses of opioids should be carefully monitored for individual and unexpected responses in an experienced palliative care unit, particularly those switched to methadone. Future studies should provide data regarding the profile of patients with difficult pain to be hospitalized.

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.

Methadone for Pain Management: A Pharmacotherapeutic Review

Methadone is increasingly being used for its analgesic properties. Despite the increasing popularity, many healthcare providers are not familiar with methadone's complex pharmacology and best practices surrounding its use. The purpose of this narrative review article is to discuss the pharmacology of methadone, the evidence surrounding methadone's use in acute pain management and both chronic cancer and non-cancer pain settings, as well as highlight pertinent safety, monitoring, and opioid rotation considerations. Methadone has a unique mechanism of action when compared with all other opioids and for this reason methadone has come to hold a niche role in the management of opioid-induced hyperalgesia and central sensitization. Understanding of the mechanisms of variability in methadone disposition and drug interactions has evolved over the years, with the latest evidence revealing that CYP 2B6 is the major determinant of methadone elimination and plays a key role in methadone-related drug interactions. From an acute pain perspective, most studies evaluating the use of intraoperative intravenous methadone have reported lower pain scores and post-operative opioid requirements. Oral methadone is predominantly used as a second-line opioid treatment for select chronic pain conditions. As a result, several oral morphine to oral methadone conversion ratios have been proposed, as have methods in which to rotate to methadone. From an efficacy standpoint, limited literature exists regarding the effectiveness of methadone in the chronic pain setting with most of the available efficacy data pertaining to methadone's use in the treatment of cancer pain. Many of the prospective studies that exist feature low participant numbers. Few clinical trials investigating the role of methadone as an analgesic treatment are currently underway. The complicated pharmacokinetic properties of methadone and risks of harm associated with this drug highlight how critically important it is that healthcare providers understand these features before prescribing/dispensing methadone. Particular caution is required when converting patients from other opioids to methadone and for this reason only experienced healthcare providers should undertake such a task. Further randomized trials with larger sample sizes are needed to better define the effective and safe use of methadone for pain management.

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.

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.

Best Practices in the Management of Nonmedical Opioid Use in Patients with Cancer-Related Pain

INTRODUCTION

Nonmedical opioid use (NMOU) in patients with cancer is a term covering a spectrum of nonprescribed opioid use. The extent to which an individual uses opioids in a nonprescribed manner will influence propensity for adverse effects such as neurotoxicity, substance use disorder, overdose, and death.

OBJECTIVES

The objectives of this study were to (A) evaluate current literature regarding management of NMOU in patients with cancer-related pain; (B) provide best practice recommendations based on evidence; and (C) integrate practices derived from the management of noncancer pain, where clinically appropriate or when the oncology literature is limited.

METHODS

This study is a narrative review.

IMPLICATIONS

Although harm from NMOU was thought to be rare among oncology patients, about one in five patients with cancer is at risk of adverse outcomes including prolonged opioid use, high opioid doses, and increased health care utilization. The management of NMOU can be challenging because pain is a multidimensional experience encompassing physical, psychological, and spiritual domains. An interdisciplinary team approach is most effective, and management strategies may include (A) education of patients and families; (B) harm reduction, including opioid switching, decreasing the overall daily dose, avoiding concurrent sedative use, and using adjuvant medications for their opioid-sparing potential; (C) managing psychological and spiritual distress with an interdisciplinary team and techniques such as brief motivational interviewing; and (D) risk mitigation by pill counts, frequent clinic visits, and accessing statewide prescription drug monitoring plans.

CONCLUSION

Although many of the management strategies for NMOU in patients with cancer-related pain are modeled on those for chronic non-cancer-related pain, there is emerging evidence that education and harm-reduction initiatives specifically for cancer-related pain are effective.

IMPLICATIONS FOR PRACTICE

Nonmedical opioid use (NMOU) in patients with cancer is a term covering a broad spectrum of nonprescribed opioid use. The extent to which an individual uses opioids in a nonprescribed manner will influence propensity for adverse effects such as neurotoxicity, substance use disorder, overdose, and death. This review evaluates the evidence for best practices in oncology and addresses limitations in the literature with supplemental evidence from noncancer chronic pain. Management recommendations for NMOU are provided, based on a combination of literature-based evidence and best clinical practice. Effective management of NMOU in oncology has the potential to improve quality of life, decrease health utilization, and improve survival.

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.

Malignant psoas syndrome associated with gynecological malignancy: Three case reports and a review of the literature

Malignant psoas syndrome (MPS) is a rare and unique cancer-associated syndrome caused by the malignant involvement of the psoas major muscle, and is characterized by ipsilateral lumbosacral plexopathy and painful hip flexion. The pain in MPS is often distressing and intractable, and there is no established effective treatment approach. Herein, the present study reports on three cases of MPS associated with gynecological malignancies, wherein symptom improvement was observed following chemotherapy or radiotherapy. Among 39 cases documented in the literature, female genital tract malignancies were the most frequent causes of MPS; however, the condition may be under-diagnosed, owing to the lack of general recognition. Considering the development of recent high-precision radiation therapy, palliative radiotherapy may serve an important role in the management of MPS. For physicians treating gynecological cancers, early detection of MPS is clinically important as this may allow patients to receive possible therapies and improve their quality of life in end-stage cancer. Further prospective studies should be performed to evaluate effective therapeutic approaches for MPS.

Methadone: Maximizing Safety and Efficacy for Pain Control in Patients with Cancer

Methadone is a valuable opioid in the management of patients who have cancer with pain. Methadone is a mu-, kappa-, and delta-opioid agonist, and an N-methyl-D-aspartate receptor antagonist. These mechanisms of action make methadone an attractive option for complex pain syndromes. It is critically important that providers consider a patient's risk status before beginning methadone. Careful consideration must be given to dosing methadone in both opioid-naïve and opioid-tolerant patients, with vigilant monitoring for therapeutic effectiveness and potential toxicity until the patient achieves steady state.

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 as a "Tumor Theralgesic" against Cancer

Methadone has beneficial characteristics as an analgesic against cancer pain, including high bioavailability, multiple receptor affinities, and lack of active metabolites that might induce adverse side effects. However, methadone has an own pharmacological profile that should be considered in the treatment of cancer patients. There is evidence from preclinical studies that methadone could also elicit antitumor activity by downregulating the threshold of apoptosis and to enhance the effects of different chemotherapeutic agents. This confirms the concept of using methadone as a chemosensitizer in the future treatment of cancer. Our article discusses major issues about the role of methadone as a possible “tumor theralgesic,” combining tumor therapeutic and analgesic activities.