Methadone initiation and rotation in the outpatient setting for patients with cancer pain

Clinical Presentation and Management of Malignant Psoas Syndrome: A Scoping Review of Case Reports and Case Series

Malignant psoas syndrome (MPS) is a rare and underreported clinical syndrome that significantly impacts the quality of life of cancer patients through metastatic infiltration of the iliopsoas muscle. Patients suffering from MPS often present with painful hip flexion, loss of mobility, and immense pain in their legs and back. The current literature describing the clinical presentation, management, and prognosis of MPS is limited primarily to case reports and outdated literature reviews. There remains a gap in the current knowledge of MPS and in the management of this complex cancer-related pain syndrome. Thus, this scoping review aimed to map current case reports and case series on MPS for clinical presentation, treatment modalities, and resulting prognoses of MPS in late-stage cancer patients. A systemized search using the databases Embase and PubMed (Medline) was conducted to access case reports and case series published between January 1990 and October 2022 that met the study's inclusion criteria: (1) adult patients with metastatic cancer; (2) MPS symptoms secondary to infiltration of iliopsoas; (3) clinical presentation, treatment modality, and prognosis; and (4) English-language text. Our search strategy yielded 1926 citations. After removing 629 duplicates, 1,283 reports were excluded due to failure to meet eligibility criteria (n=1,271) or inaccessibility (n=12). Using the JBI appraisal tools for case reports and case series, a total of 14 articles remained for the final review. With histories of either genitourinary, hepatic, gastric, or skin cancer, each case reported new onset intense pain in the legs, back, abdomen, or pelvis with associated symptoms such as flexion of the hip or gait disorder. A computerized tomography (CT) scan, magnetic resonance imaging (MRI), or positron emission tomography (PET) scan typically confirmed metastasis into the iliopsoas causing these symptoms, which suggested MPS. Each case utilized two to seven different pain management strategies to alleviate MPS symptoms. Many cases first used opioids for pain relief. Following a necessitated increase in morphine equivalent daily dose, a subsequent increase in the strength of analgesic, change in route of administration, and integration of combination drug therapy were generally added to the treatment regime. Many cases reported successful management of symptoms through utilizing methadone, radiation therapy, botulinum toxin injection, increased opioid dosage, or epidural catheter administration of opioids. A unified clinical definition of MPS may be required to inform physicians of this syndrome to help support clinical decisions regarding treatments for patients. The studies indicated that a clearer guideline for treatment protocol may be warranted as most cases reported utilizing various treatment medication dosages and procedures with vastly differing results.

Levorphanol as a Second Line Opioid in Cancer Patients Presenting to an Outpatient Supportive Care Center: An Open-label Study

CONTEXT

Levorphanol is a potent opioid agonist and NMDA receptor blocker with minimal drug interactions, and there are few reports of its use in cancer patients.

OBJECTIVES

We aimed to determine the frequency of successful opioid rotation (OR) to levorphanol and the median opioid rotation ratio (ORR) from Morphine Equivalent Daily Dose (MEDD).

METHODS

This is a prospective, single-group, interventional study. Cancer outpatients requiring an OR and receiving a MEDD of 60-300 mg were rotated to levorphanol using a ratio of 10:1 and assessed daily for 10-day. Successful OR was defined as a 2-point improvement in the Edmonton Symptom Assessment System (ESAS) pain score on day 10 or achieving the personalized pain goal between days 3-10 in patients with uncontrolled pain or resolution of opioid side effects (OSE) in those undergoing OR for OSE alone. The ORR to levorphanol was calculated using net-MEDD (MEDD before OR minus the MEDD of the breakthrough opioid used along with levorphanol after OR).

RESULTS

Forty patients underwent OR to levorphanol, and uncontrolled pain 35/40 (87.5%) was the most common indication. The median net-MEDD and levorphanol doses were 95 and 10 mg, respectively, and 33/40 (82.5%) had a successful OR with a median (IQR) ORR of 8.56 (7.5-10). Successful OR was associated with significant improvement in ESAS and OSE scale scores. There was a strong association between MEDD and levorphanol dose.

CONCLUSION

This study provided preliminary data that cancer patients could be successfully rotated to levorphanol using an ORR of 8.5. Levorphanol was associated with improved pain and symptom control and was well- tolerated.

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 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.

OUP accepted manuscript

Aim

The aim of this study was to assess the efficacy and adverse effects of methadone when used as first-line therapy in patients that are either receiving low doses of opioids or none.

Methods

Patients with advanced cancer were prospectively assessed. Opioid-naive patients (L-group) were started with methadone at 6 mg/day. Patients receiving weak or other opioids in doses of <60 mg/day of OME (H-group) were started with methadone at 9 mg/day. Methadone doses were changed according to the clinical needs to obtain the most favorable balance between analgesia and adverse effects. Edmonton Symptom Asssement Score (ESAS), Memorial Delirium Assessment Score (MDAS), doses of methadone, and the use of adjuvant drugs were recorded before starting the study treatment (T0), 1 week after (T7), 2 weeks after (T14), 1 month after (T30), and 2 months after (T60). Methadone escalation index percent (MEI%) and in mg (MEImg) were calculated at T30 and T60.

Results

Eighty-two patients were assessed. In both groups H and L, there were significant changes in pain and symptom intensity at the different times during the study. Adverse effects as causes of drop-out were minimal. Mean MEImg was 0.09 (SD 0.28) and 0.02 (SD 0.07) at T30 and T60, respectively. MEI% was 1.01 (SD 3.08) and 0.27 (SD 0.86) at T30 and T60, respectively.

Conclusion

Methadone used as a first-line opioid therapy provided good analgesia with limited adverse effects and a minimal opioid-induced tolerance.

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.

CYP2B6 Functional Variability in Drug Metabolism and Exposure Across Populations-Implication for Drug Safety, Dosing, and Individualized Therapy

Adverse drug reactions (ADRs) are one of the major causes of morbidity and mortality worldwide. It is well-known that individual genetic make-up is one of the causative factors of ADRs. Approximately 14 million single nucleotide polymorphisms (SNPs) are distributed throughout the entire human genome and every patient has a distinct genetic make-up which influences their response to drug therapy. Cytochrome P450 2B6 (CYP2B6) is involved in the metabolism of antiretroviral, antimalarial, anticancer, and antidepressant drugs. These drug classes are commonly in use worldwide and face specific population variability in side effects and dosing. Parts of this variability may be caused by single nucleotide polymorphisms (SNPs) in the CYP2B6 gene that are associated with altered protein expression and catalytic function. Population variability in the CYP2B6 gene leads to changes in drug metabolism which may result in adverse drug reactions or therapeutic failure. So far more than 30 non-synonymous variants in CYP2B6 gene have been reported. The occurrence of these variants show intra and interpopulation variability, thus affecting drug efficacy at individual and population level. Differences in disease conditions and affordability of drug therapy further explain why some individuals or populations are more exposed to CYP2B6 pharmacogenomics associated ADRs than others. Variabilities in drug efficacy associated with the pharmacogenomics of CYP2B6 have been reported in various populations. The aim of this review is to highlight reports from various ethnicities that emphasize on the relationship between CYP2B6 pharmacogenomics variability and the occurrence of adverse drug reactions. In vitro and in vivo studies evaluating the catalytic activity of CYP2B6 variants using various substrates will also be discussed. While implementation of pharmacogenomic testing for personalized drug therapy has made big progress, less data on pharmacogenetics of drug safety has been gained in terms of CYP2B6 substrates. Therefore, reviewing the existing evidence on population variability in CYP2B6 and ADR risk profiles suggests that, in addition to other factors, the knowledge on pharmacogenomics of CYP2B6 in patient treatment may be useful for the development of personalized medicine with regards to genotype-based prescription.

First-line methadone for cancer pain: titration time analysis

BACKGROUND

Methadone is a low-cost, strong opioid that is increasingly used as a first-line treatment for pain in palliative care (PC). Its long and unpredictable half-life and slow elimination phase can make titration challenging. Evidence for titration modalities is scarce.

OBJECTIVE

To describe the titration phase of the treatment with low-dose first-line methadone and the use of methadone for breakthrough pain.

METHODS

Prospective study with strong opioid-naïve patients with moderate to severe cancer pain followed at a tertiary PC unit in Argentina. Starting methadone dose was 2.5-5 mg/day every 8, 12, or 24 h. Titration allowed daily dose increases from day 1, and prescription of oral methadone 2.5 mg every 2 h with a maximum of 3 rescue doses/day for breakthrough pain. Pain control, methadone stabilization dose, and adverse effects, among other variables, were daily assessed over the first 7 days (T0-T7).

RESULTS

Sixty-two patients were included. Initial median (IQR) methadone dose was 5 (2.5) mg/day. Pain intensity decreased from a median (IQR) of 8 (2.3) at T0 to 4 (2.3) at T1 and remained ≤ 4 until T7 (all p < 0.0001 compared to T0). Similar results were obtained through the categorical and tolerability scales for pain. Fifty patients (81%) reached pain control, 66% in the first 48 h. Methadone daily doses at T2 and T7 were higher than that at T0: 7.5 (3) and 6.7 (5.5) versus 5 (2.5), respectively (all p < 0.05). The opioid escalation index at T7 was 1.7%. The median (IQR) number of rescues, stabilization dose, and time for stabilization was 0 (1), 5(4.5) mg, and 3(2) days, respectively. Two patients were discontinued due to delirium. All other side effects were mild.

CONCLUSIONS

First-line, low-dose methadone using rescue methadone resulted in a pronounced and rapid decrease in pain, with minimal need for titration and for breakthrough doses, and no evidence of accumulation or sedation by the end of the week.

Methadone-mediated sensitization of glioblastoma cells is drug and cell line dependent

PURPOSE

D,L-methadone (MET), an analgesic drug used for pain treatment and opiate addiction, has achieved attention from oncologists and social media as possible chemoensitizing agent in cancer therapy, notably brain cancer (glioblastoma multiforme, GBM). MET has been reported to enhance doxorubicin-induced cytotoxicity in GBM cells via activation of the µ-opioid receptor (MOR). Here, we extended this work and quantified the toxic effect of MET in comparison to other opioids alone and in combination with doxorubicin and the clinically more relevant alkylating drug temozolomide (TMZ), using a set of GBM cell lines and primary GBM cells.

METHODS

MOR expression in GBM cells was investigated by immunofluorescence and immunoblotting. Resistance to drugs alone and in combination with anticancer drugs was assessed by MTT assays. Concentration effect curves were fitted by nonlinear regression analysis and IC50 values were calculated. Apoptosis and necrosis rates were determined by annexin V/propidium iodide (PI)-flow cytometry.

RESULTS

MET alone was cytotoxic in all GBM cell lines and primary GBM cells at high micromolar concentrations (IC50 ~ 60-130 µM), observed both in the metabolic MTT assay and by quantifying apoptosis and necrosis, while morphine and oxycodone were not cytotoxic in this concentration range. Naloxone was not able to block MET-induced cytotoxicity, indicating that cell death-inducing effects of MET are not MOR-dependent. We recorded doxorubicin and TMZ concentration- response curves in combination with fixed MET concentrations. MET enhanced doxorubicin-induced cytotoxicity in only one cell line, and in primary cells it was observed only in a particular MET concentration range. In all assays, MET was not effective in sensitizing cells to TMZ. In two cell lines, MET even decreased the cell's sensitivity to TMZ.

CONCLUSION

MET was found to be cytotoxic in GBM cells in vitro only at high, clinically not relevant concentrations, where it was effective in inducing apoptosis and necrosis. Sensitizing effects were only observed in combination with doxorubicin, but not with TMZ, and are dependent on cell line and the applied drug concentration. Therefore, our findings do not support the use of MET in the treatment of GBM in combination with TMZ, as no sensitizing effect of MET was observed.

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.

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.

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

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

Adult Cancer Pain, Version 3.2019, NCCN Clinical Practice Guidelines in Oncology

In recent years, the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Adult Cancer Pain have undergone substantial revisions focusing on the appropriate and safe prescription of opioid analgesics, optimization of nonopioid analgesics and adjuvant medications, and integration of nonpharmacologic methods of cancer pain management. This selection highlights some of these changes, covering topics on management of adult cancer pain including pharmacologic interventions, nonpharmacologic interventions, and treatment of specific cancer pain syndromes. The complete version of the NCCN Guidelines for Adult Cancer Pain addresses additional aspects of this topic, including pathophysiologic classification of cancer pain syndromes, comprehensive pain assessment, management of pain crisis, ongoing care for cancer pain, pain in cancer survivors, and specialty consultations.

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.

Efficacy of D,L-methadone in the treatment of glioblastoma in vitro

AIM

Recently, D,L-methadone has been put forward as adjuvant treatment in glioblastoma (GBM).

METHODS

We analyzed the μ-opioid receptor expression in a set of GBM cell lines and investigated the efficacy of D,L-methadone alone and in combination with temozolomide (TMZ). Results & conclusion: Expression of the μ-opioid receptor was similar in the tested cell lines. High concentrations of D,L-methadone induced apoptosis in all cell lines and showed treatment interaction with TMZ. However, in lower dosages, reflecting clinically attainable concentrations, D,L-methadone alone showed no efficacy, and induced even higher proliferation in one specific cell line. Also, no interaction with TMZ was observed. These results suggest caution to the premature use of D,L-methadone in the treatment of GBM patients.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

Methadone as a First-Line Opioid in Cancer Pain Management: A Systematic Review

AIM

The objective of this review was to assess the existent evidence for the use of methadone as a first-line therapy in cancer pain management.

METHODS

A systematic literature search on MEDLINE and Embase databases was carried out from each database, setting up the date to August 30, 2017. Studies were included if methadone was a first-line drug as a Step 3 of World Health Organization analgesic ladder, or at low doses (Step 2), if they were conducted in adult patients with cancer pain, and if they contained outcomes on pain- and opioid-related adverse effects.

RESULTS

The initial search yielded 219 records. Ten articles were considered after the initial screening according to inclusion and exclusion criteria. They included three longitudinal open-label studies. In two studies methadone was initiated at low doses (≤10 mg/day). These studies suggested that methadone was effective in providing analgesia and well tolerated as first opioid at different starting doses and in different conditions and settings. Five additional studies were randomized controlled studies with morphine in patients who had received opioids for moderate pain. Methadone, compared with oral morphine, or transdermal fentanyl, either at low (Step 2 level) or relatively higher doses (Step 3 level), provided similar analgesia with similar adverse effects profile with limited dose escalation in time.

CONCLUSION

Available data are not sufficient to draw net conclusion. However, open-label and controlled studies have shown that methadone may be effective as first-line drug in the management of cancer pain, providing analgesia and adverse effect profiles similar to those produced by other opioids. The finding that methadone doses tend to remain stable suggests that metabolic characteristics and extraopioid analgesic effects, as its well antihyperalgesic properties may be interesting potential advantages. Further studies should provide information regarding the long-term use of methadone or the need to switch from methadone to other opioids when a loss of analgesic response occurs.

Practical Pharmacology of Methadone: A Long-acting Opioid

Methadone is a naturally long-acting analgesic with unique pharmacodynamic and pharmacokinetic properties compared to other opioids, available now in India, to treat severe pain. It has the potential to dramatically relieve suffering among patients with serious illness who are living with persistent physical pain. However, clinicians must appreciate its unique pharmacologic properties and its use in clinical practice safely and effectively. The available formulation in India is a racemic mixture of the S- and R-enantiomers, and as such, it will have a propensity for drug-drug and drug-genetic interactions that can increase the risk of Torsades de Point and respiratory depression. Appropriate patient selection, careful dosing and thorough monitoring of methadone will mitigate these risks.

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.

Methadone for Pain Management: Past, Present and Future

Methadone for pain management in this article describes briefly pain, methadone as a Level 3 World Health Organization ladder opioid in the context of India and rest of the world, as well as the relationship to past, present, and future possibilities of pain management. Acute pain is proportional to the injury most of the times, and such proportionality may not exist in chronic pain. Pain management over decades has changed because of knowledge and availability of molecules and compounds to reduce chronic pain. Naturally occurring opioids from "poppy" such as morphine and heroin were available through cultivation and trade for pain management and recreational use in different parts of the world for centuries. Methadone has been a synthetic molecule discovered in the 1930s in Germany. It has been used for harm reduction for opioid use disorder in the form of "methadone maintenance treatment". This program exists since the 1950s while pain management started around the late 1970s in Europe and North America. More recently, the knowledge of acute and chronic pain at a molecular level, including ion channel modification, allowed the use of coanalgesics and opioids prudently. The concept of "total pain, neuroplasticity, and neurotransmitters" how they could be modified for better pain management with pharmaceuticals and nonpharmacological methods are being investigated, and evidence is being practiced clinically. In the present context, education for physicians, allied health professionals, patients, and family caregivers is important. Education to the physicians can skill and capacity build in the community and can be associated with educational research and peer-reviewed publications. The future remains promising, as innovations such as pharmacogenomics, nanotechnology, molecular, and quantum biology may create evidence, along with physical and psychological rehabilitation, to prevent and holistically better pain management.

Practical Guide for Using Methadone in Pain and Palliative Care Practice

Since the 2014 Amendment to the NDPS Act methadone has been released in India for pain management. The methadone is supplied as racemic mixture with R & S methadone with benefit in pain management and associated adverse effects. Physicians need to be aware of adverse effects so that methadone can be administered safely. Similarly, patients and families need to store and use methadone carefully and experience the benefits and not increase the risk of further morbidity. Considerable amount of literature on methadone is available and sometimes conflicting, hence the article is attempting to guide a physician to use methadone safely to acquire experience and expertise over time.

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.

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.

The Opioid Rotation Ratio From Transdermal Fentanyl to "Strong" Opioids in Patients With Cancer Pain

CONTEXT

One-third of cancer patients require opioid rotation (OR) to treat uncontrolled pain or opioid-induced neurotoxicity. Although fentanyl is the most frequently rotated opioid in cancer patients, the accurate opioid rotation ratio (ORR) from transdermal fentanyl (TDF) to other so-called "strong" opioids is unknown.

OBJECTIVES

We aimed to determine the ORR of TDF to strong opioids, as measured by morphine equivalent daily dose (MEDD).

METHODS

We reviewed 2471 consecutive patient visits (938 patients) to our supportive care center for an OR from TDF to strong opioids. Information regarding demographics, symptoms, and MEDD was collected in patients who followed up within six weeks. Linear regression analysis was used to estimate the ORR between TDF dose and net MEDD (MEDD after OR minus MEDD of the breakthrough opioid used along with TDF before OR).

RESULTS

Among 47 eligible patients, the median age was 54 years, 53% were male, and 77% had advanced cancer. The median time to follow-up was 14 days. Uncontrolled pain (83%) was the most common reason for OR. In patients with OR and no worsening of pain at follow-up (n = 41), the median ORR (range) from TDF mg/day to net MEDD mg/day was 100 (12.5-217) and from TDF mcg/hour to net MEDD was 2.4 (0.3-5.2); the correlation of TDF dose to net MEDD was 0.60 (P < 0.0001).

CONCLUSION

The median ORR from TDF mg/day to MEDD is 100 and from TDF mcg/hour to MEDD is 2.4, suggesting that TDF 100 mcg/hour is equivalent to an MEDD of 240 mg.

Definition, diagnosis and treatment strategies for opioid-induced bowel dysfunction–Recommendations of the Nordic Working Group

Background and aims

Opioid-induced bowel dysfunction (OIBD) is an increasing problem due to the common use of opioids for pain worldwide. It manifests with different symptoms, such as dry mouth, gastro-oesophageal reflux, vomiting, bloating, abdominal pain, anorexia, hard stools, constipation and incomplete evacuation. Opioid-induced constipation (OIC) is one of its many symptoms and probably the most prevalent. The current review describes the pathophysiology, clinical implications and treatment of OIBD.

Methods

The Nordic Working Group was formed to provide input for Scandinavian specialists in multiple, relevant areas. Seven main topics with associated statements were defined. The working plan provided a structured format for systematic reviews and included instructions on how to evaluate the level of evidence according to the GRADE guidelines. The quality of evidence supporting the different statements was rated as high, moderate or low. At a second meeting, the group discussed and voted on each section with recommendations (weak and strong) for the statements.

Results

The literature review supported the fact that opioid receptors are expressed throughout the gastrointestinal tract. When blocked by exogenous opioids, there are changes in motility, secretion and absorption of fluids, and sphincter function that are reflected in clinical symptoms. The group supported a recent consensus statement for OIC, which takes into account the change in bowel habits for at least one week rather than focusing on the frequency of bowel movements. Many patients with pain receive opioid therapy and concomitant constipation is associated with increased morbidity and utilization of healthcare resources. Opioid treatment for acute postoperative pain will prolong the postoperative ileus and should also be considered in this context. There are no available tools to assess OIBD, but many rating scales have been developed to assess constipation, and a few specifically address OIC. A clinical treatment strategy for OIBD/OIC was proposed and presented in a flowchart. First-line treatment of OIC is conventional laxatives, lifestyle changes, tapering the opioid dosage and alternative analgesics. Whilst opioid rotation may also improve symptoms, these remain unalleviated in a substantial proportion of patients. Should conventional treatment fail, mechanism-based treatment with opioid antagonists should be considered, and they show advantages over laxatives. It should not be overlooked that many reasons for constipation other than OIBD exist, which should be taken into consideration in the individual patient.

Conclusion and implications

It is the belief of this Nordic Working Group that increased awareness of adverse effects and OIBD, particularly OIC, will lead to better pain treatment in patients on opioid therapy. Subsequently, optimised therapy will improve quality of life and, from a socio-economic perspective, may also reduce costs associated with hospitalisation, sick leave and early retirement in these patients.

Methadone as first-line opioid treatment for cancer pain in a developing country palliative care unit

PURPOSE

The use of methadone for cancer pain is limited by the need of expertise and close titration due to variable half-life. Yet, it is a helpful palliative strategy in low-resources countries given its long-acting effect at low cost and worth additional study. Our aim was to describe the prescription and outcomes of methadone as a first-line treatment for cancer pain in a tertiary palliative care unit (PCU) in Argentina.

METHODS

Retrospective review of medical records of patients with moderate to severe cancer pain seen at the PCU in 1-year period, who initiated strong opioids at the first consultation. Data collected during the first month of treatment included disease and pain characteristics, initial and final opioid type and dose and need for opioid rotation.

RESULTS

Methadone was the most frequent opioid both at the initial and last assessment (71 and 66 % of the prescriptions). In all, treatment with strong opioids provided considerable decrease in pain intensity (p < 0.001) with low and stable opioid dose. Median and interquartile range (IR) of oral morphine equivalent daily dose (OMEDD) was 26 (16-32) and 39 (32-55) mg for initial and final assessments, respectively (p = 0.3). In patients initiated with methadone, the median (IR) daily methadone dose was 5 (4-6) mg at first and 7.5 (6-10) mg at final assessment, and the median (IR) index of opioid escalation was 0 (0-4) mg; (p < 0.05). Patients on methadone underwent less percentage of opioid rotation (15 versus 50 %; p < 0.001) and longer time to rotation (20.6 ± 4.4 versus 9.0 ± 2.7 days; p < 0.001) than patients on other opioids.

CONCLUSIONS

Results indicate the preference of methadone as first-line strong opioid treatment in a PCU, providing good pain relief at low doses with low need for rotation. Several considerations about the costs of strong opioids in the region are given.

Methadone Pharmacogenetics: CYP2B6 Polymorphisms Determine Plasma Concentrations, Clearance, and Metabolism

BACKGROUND

Interindividual variability in methadone disposition remains unexplained, and methadone accidental overdose in pain therapy is a significant public health problem. Cytochrome P4502B6 (CYP2B6) is the principle determinant of clinical methadone elimination. The CYP2B6 gene is highly polymorphic, with several variant alleles. CYP2B6.6, the protein encoded by the CYP2B6*6 polymorphism, deficiently catalyzes methadone metabolism in vitro. This investigation determined the influence of CYP2B6*6, and other allelic variants encountered, on methadone concentrations, clearance, and metabolism.

METHODS

Healthy volunteers in genotype cohorts CYP2B6*1/*1 (n = 21), CYP2B6*1/*6 (n = 20), and CYP2B6*6/*6 (n = 17), and also CYP2B6*1/*4 (n = 1), CYP2B6*4/*6 (n = 3), and CYP2B6*5/*5 (n = 2) subjects, received single doses of IV and oral methadone. Plasma and urine methadone and metabolite concentrations were determined by tandem mass spectrometry.

RESULTS

Average S-methadone apparent oral clearance was 35 and 45% lower in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively, compared with CYP2B6*1/*1. R-methadone apparent oral clearance was 25 and 35% lower in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively, compared with CYP2B6*1/*1. R- and S-methadone apparent oral clearance was threefold and fourfold greater in CYP2B6*4 carriers. IV and oral R- and S-methadone metabolism was significantly lower in CYP2B6*6 carriers compared with that of CYP2B6*1 homozygotes and greater in CYP2B6*4 carriers. Methadone metabolism and clearance were lower in African Americans in part because of the CYP2B6*6 genetic polymorphism.

CONCLUSIONS

CYP2B6 polymorphisms influence methadone plasma concentrations, because of altered methadone metabolism and thus clearance. Genetic influence is greater for oral than IV methadone and S- than R-methadone. CYP2B6 pharmacogenetics explains, in part, interindividual variability in methadone elimination. CYP2B6 genetic effects on methadone metabolism and clearance may identify subjects at risk for methadone toxicity and drug interactions.

Cancer pain management: safe and effective use of opioids

Pain remains a serious consequence of cancer and its treatment. Although significant advances have been made in providing effective cancer pain control, barriers persist. Lack of knowledge, limited time, financial restrictions, and diminished availability of necessary medications serve as significant obstacles. Safe and effective opioid use in a patient with cancer requires skill to overcome these challenges. Understanding the mechanism of action, along with the pharmacokinetics and pharmacodynamics, of opioids will lead to appropriate selection, dosing, and titration of these agents. Rotation from one opioid or route to another is an essential proficiency for oncologists. As opioid-related adverse effects often occur, the oncology team must be expert in preventing and managing constipation, nausea, sedation, and neurotoxicities. An emerging concern is overtreatment-the excessive and prolonged use of opioids in patients when these agents may produce more harm than benefit. This can occur when opioids are used inappropriately to treat comorbid psychologic issues such as anxiety and depression. Recognizing risk factors for overuse along with key components of universal precautions will promote safe use of these medications, supporting adherence and preventing diversion, thereby protecting the patient, the prescriber, and the community. Because substance use disorders are not rare in the oncology setting, attention must be given to the balance of providing analgesia while limiting harm. Caring for patients with substance misuse requires compassionate, multidisciplinary care, with input from supportive oncology/palliative care as well as addiction specialists.

The opioid rotation ratio of hydrocodone to strong opioids in cancer patients

PURPOSE

Cancer pain management guidelines recommend initial treatment with intermediate-strength analgesics such as hydrocodone and subsequent escalation to stronger opioids such as morphine. There are no published studies on the process of opioid rotation (OR) from hydrocodone to strong opioids in cancer patients. Our aim was to determine the opioid rotation ratio (ORR) of hydrocodone to morphine equivalent daily dose (MEDD) in cancer outpatients.

PATIENTS AND METHODS

We reviewed the records of consecutive patient visits at our supportive care center in 2011-2012 for OR from hydrocodone to stronger opioids. Data regarding demographics, Edmonton Symptom Assessment Scale (ESAS), and MEDD were collected from patients who returned for follow-up within 6 weeks. Linear regression analysis was used to estimate the ORR between hydrocodone and MEDD. Successful OR was defined as 2-point or 30% reduction in the pain score and continuation of the new opioid at follow-up.

RESULTS

Overall, 170 patients underwent OR from hydrocodone to stronger opioid. The median age was 59 years, and 81% had advanced cancer. The median time between OR and follow-up was 21 days. We found 53% had a successful OR with significant improvement in the ESAS pain and symptom distress scores. In 100 patients with complete OR and no worsening of pain at follow-up, the median ORR from hydrocodone to MEDD was 1.5 (quintiles 1-3: 0.9-2). The ORR was associated with hydrocodone dose (r = -.52; p < .0001) and was lower in patients receiving ≥40 mg of hydrocodone per day (p < .0001). The median ORR of hydrocodone to morphine was 1.5 (n = 44) and hydrocodone to oxycodone was 0.9 (n = 24).

CONCLUSION

The median ORR from hydrocodone to MEDD was 1.5 and varied according to hydrocodone dose.

Toward a systematic approach to opioid rotation

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

Palliative care research: lessons learned by our team over the last 25 years

BACKGROUND

In the last 25 years, palliative care has made major progress as an interdisciplinary specialty that addresses quality-of-life issues for patients with life-limiting illnesses and their families. Research by numerous investigators has contributed to our increasing body of knowledge to support an evidence-based practice.

AIM

We highlight some lessons learned by our group in the process of conducting palliative care research, focusing in particular on symptom assessment; the management of pain, fatigue, cachexia, dyspnea, delirium, and opioid-induced neurotoxicity; and outcomes of our palliative care program.

DESIGN

Narrative review of selected literature, focusing on studies conducted by our group.

DATA SOURCES

This article is based on the Second Vittorio Ventafridda Memorial Lecture by Dr Eduardo Bruera, delivered at the European Association for Palliative Care, Trondheim, Norway on 8 June 2012.

RESULTS

For each topic, we review some of the pivotal studies in palliative care, discuss the challenges in research design, and outline possible directions for future research.

CONCLUSIONS

We conclude by sharing some of what we learned about the processes, pearls, and pitfalls of palliative care research.

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.

Adult cancer pain

Pain is a common symptom associated with cancer and its treatment. Pain management is an important aspect of oncologic care, and unrelieved pain significantly comprises overall quality of life. These NCCN Guidelines list the principles of management and acknowledge the range of complex decisions faced in the management oncologic pain. In addition to pain assessment techniques, these guidelines provide principles of use, dosing, management of adverse effects, and safe handling procedures of pharmacologic therapies and discuss a multidisciplinary approach for the management of cancer pain.

Opioid prescribing practices before and after initiation of palliative care in outpatients

CONTEXT

Prescription Monitoring Programs (PMPs) are being developed and implemented in many states to deter abuse, diversion, and overdose, and physicians may use PMPs to help guide their treatment choices for individual patients.

OBJECTIVES

To evaluate the changes in prescribing practices and pain score outcomes in patients with cancer before and after an initial consult in an outpatient palliative care clinic.

METHODS

This is a retrospective study with a sample of 60 consecutive patients who had been referred by oncologists for difficult-to-manage pain and whose initial palliative care consult was with either of the two physicians in the outpatient palliative care clinic. For each patient, lists were compiled of all prescriptions for controlled medications and filled for the 90-day periods immediately before and after the initial consult. Data from patient charts were combined with information from the Virginia PMP, which included prescriptions written before and after the initiation of palliative care, written by prescribers both inside and outside the palliative care clinic.

RESULTS

After the palliative care consult, the proportion of patients on long-acting opioids increased from 45% to 73%. Self-reported pain outcomes, which were compiled for the subset of patients who continued palliative care for at least 60 days, showed a median decrease of two units on a 0-10 scale. A decrease was seen in the use of medications that compound acetaminophen with opioids.

CONCLUSION

Data from a PMP proved useful in understanding the changes in a population of patients. Favorable changes were observed in prescribing practices and pain outcomes.

The use of very-low-dose methadone for palliative pain control and the prevention of opioid hyperalgesia

BACKGROUND

Opioid dose escalation may cause hyperalgesia, mediated by the N-methyl-D-aspartate (NMDA) pathway. Methadone is an atypical opioid that inhibits hyperalgesia through NMDA-blockade, especially at low doses.

OBJECTIVE

To evaluate the efficacy of using very-low-dose methadone as the sole long-acting opioid agent in a hospice practice.

DESIGN

A retrospective, observational study of the use of methadone, ≤15 mg daily, with as-needed short-acting opiates. Adjuvant nonopioid medications included haloperidol, which may have NMDA-blocking effects.

SETTING/SUBJECTS

We reviewed the records of 240 patients admitted to a community-based hospice from July 1, 2011 to April 1, 2012, with data collected until hospice discharge or until April 30, 2012.

MEASUREMENTS

Descriptive statistics were used to summarize patient demographics, medication regimens, and reported pain scores measured on a numeric rating scale from 0 to 10.

RESULTS

All patients received short-acting opiates, in a morphine-equivalent dose of 5 mg every 4 hours as needed, while 40% also received methadone at a median daily dose of 5 mg. Of those on methadone, almost half received scheduled haloperidol. The population had a median reported pain score of 0 and a peak score of 3, with similar results seen for cancer and noncancer groups. Two-thirds of patients never reported a pain score greater than 3.

CONCLUSION

The use of very-low-dose methadone in conjunction with adjuvant haloperidol resulted in excellent pain control without dose escalation or opioid-induced hyperalgesia, for both cancer and noncancer diseases. We conclude that low-dose methadone should be part of first-line treatment in palliative pain management.

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

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

Opioid switching in patients with advanced cancer followed at home. A retrospective analysis

CONTEXT

Opioid switching has been found to improve opioid responsiveness in different conditions. However, data on opioid switching performed at home are almost nonexistent, despite the fact that most patients are followed at home.

OBJECTIVES

The aim of this retrospective survey was to determine frequency, indications, usefulness, and safety of opioid switching when treating advanced cancer-related pain in patients followed at home.

METHODS

A retrospective review of data from patients with advanced cancer followed at home by three home care teams for a period of two years was performed. Patients who had their opioids switched were selected. Reasons for switching opioid doses and routes of administration and outcomes were collected.

RESULTS

Two hundred one (17%) of 1141 patients receiving "strong" opioids were switched. The mean Karnofsky Performance Status score was 35.6, and the median survival was 30 days. The most frequent reason to switch was for convenience, and the most frequent switch was to parenteral morphine. In most patients, a better analgesic response was observed. Patients who were switched to parenteral morphine had a shorter survival in comparison with other opioid sequences (P<0.0005). After switching, opioid doses were increased by 23% and 41%, after a week and at time of death, respectively.

CONCLUSION

Opioid switching was useful for most patients in the home environment, at least in less complex circumstances, when done by experienced home care teams. Prospective studies are needed to provide information about the decision to admit to hospital for this purpose and the predictive factors that may relatively contraindicate transportation to a facility in severely ill patients.

Frequency, outcome, and predictors of success within 6 weeks of an opioid rotation among outpatients with cancer receiving strong opioids

BACKGROUND

Opioid rotation is used to treat uncontrolled pain and/or opioid-related adverse effects. Our aim was to determine the frequency, indications, outcomes, and predictors of successful opioid rotation in outpatients with cancer.

METHODS

Medical records of consecutive outpatients with cancer who received strong opioids and returned for follow-up visit within ≤6 weeks to our supportive care center from January to December 2008 were reviewed. Data on patient characteristics, symptoms, opioid use, indications for opioid rotation, outcomes, and morphine equivalent daily dose were collected. Successful opioid rotation was defined as a two-point or 30% reduction in the symptom score or the resolution of opioid-induced neurotoxicity and continuation of the new opioid at follow-up.

RESULTS

Opioid rotation was performed in 120 of 385 patients (31%). The median patient age was 55 years. There were 6/120 patients with missing data. Of the 114 evaluable patients, 68 (60%) were men, 81 (71%) were white, 27 (24%) had gastrointestinal cancer, and 90 (80%) had advanced-stage disease. The median Eastern Cooperative Oncology Group score was 1 (interquartile range: 1-2) and the median time between opioid rotation and follow-up was 14 days (interquartile range: 7-21 days). The most common indications for opioid rotation were uncontrolled pain (95/114; 83%) and opioid-induced neurotoxicity (13/114; 12%). A total of 35 patients (31%) had partial opioid rotation. The median improvements in pain and symptom distress score were -2 (interquartile range: -4 to 0; p < .001) and -5 (interquartile range: -14 to 7; p = .004), respectively. The morphine equivalent daily dose did not change significantly after opioid rotation (p = .156). A total of 65% of patients (74/114) had successful opioid rotation. There were no clinically significant independent predictors for successful opioid rotation.

CONCLUSION

Opioid rotation was conducted in 31% of outpatients with cancer, with a 65% success rate. The most frequent reason for opioid rotation was uncontrolled pain. There were no independent predictors for successful opioid rotation.

Opioid switching to methadone: a pharmacoepidemiological study from a national prescription database

BACKGROUND

Opioid switching to methadone is reported frequently to improve pain control in patients with an unacceptable balance between pain control and side effects during treatment with first line opioids, but carries a risk of drug accumulation and respiratory depression. To justify this risk it is required that less risky treatments are tried beforehand and that a sufficiently large proportion of patients experience a long-lasting improvement in pain control.

RESEARCH QUESTIONS

How large was the proportion of patients remaining on long term methadone treatment after a switch from a strong opioid to methadone? How long had the patients been treated with opioids before the switch to methadone?

METHODS

Longitudinal pharmacoepidemiological study from the complete national Norwegian Prescription Database.

RESULTS

One hundred and thirty (77%) cancer patients received more than one dispensed prescription of methadone. Forty-nine (40%) chronic non-malignant pain (CNMP) patients continued to have methadone prescriptions dispensed more than 6 months after the switch. Of 168 cancer patients, 48 (29%) had tried two strong opioids prior to the switch to methadone whereas 21 (12.5%) had tried three or more strong opioids. Similar numbers for 124 CNMP patients were 26 (21%) and 34 (27%), respectively.

INTERPRETATION

Opioid switching to methadone appears to provide a long lasting improvement in pain control in a significant proportion of patients. However, the study raises concerns that treatment options with less risk are not being exhausted prior to switching to methadone.

The effect of age on opioid switching to methadone: a systematic review

BACKGROUND

The aim of this review was to assess from the existing literature the effect of age on the outcome of opioid switching to methadone, and the possible influence on conversions ratios.

DISCUSSION

Older patients represent a challenge for physicians, as a further factor may play a role in dosing methadone and possibly on successful switching. Although existing data are not conclusive because this aspect did not receive particular attention in most studies, at the present time age has not been found to be independently associated with the dose ratio. Further prospective studies in a large sample of patients, subgrouped for classes of age, opioid doses, and reasons to switch, should be designed to provide more information.