A review of common methods to convert morphine to methadone

Methadone Dose and Timing of Administration as Predictors of Sleep Apnea Syndrome During Methadone Maintenance Treatment: A Retrospective Cross-sectional Study

Background

This study aimed to assess the association of sleep apnea syndrome (SAS) with methadone dose and timing of administration in patients receiving methadone maintenance treatment (MMT) for opioid use disorder (OUD).

Methods

This retrospective cross-sectional study was conducted on adult patients receiving MMT who had a nocturnal respiratory polygraphy between November 2015 and December 2021. Data on methadone treatment and polygraph recording, including the apnea-hypopnea index (AHI) were collected.

Findings

A total of 40 patients, mostly male (72.5%), with a mean age of 35±6.7 years and a mean body mass index (BMI) of 25.1±4.5 kg/m2 were included. The daily dose of methadone was significantly associated with an AHI≥15 events/h as well as an AHI≥30 events/h, even after adjustment for age, gender, BMI, and benzodiazepine use. However, these associations were not preserved when the time of administration (day vs evening) was considered, while the evening administration was significantly associated with an AHI≥15 events/h. The best sensitivity and specificity for the prediction of AHI≥15 events/h and AHI≥30 events/h were obtained with daily methadone doses of≥72.5 mg and 77.5 mg, respectively.

Conclusion

In this sample of MMT patients, methadone doses of 72.5 mg and 77.5 mg were the best cut-off values for predicting AHI≥15 and≥30 events/h, respectively, especially when taken in the evening. These results should draw clinicians' attention to the importance of SAS screening, and further studies are needed, notably comparisons with buprenorphine.

Buprenorphine/naloxone versus methadone opioid rotation in patients with prescription opioid use disorder and chronic pain: study protocol for a randomized controlled trial

BACKGROUND

Opioids are effective in pain-management, but long-term opioid users can develop prescription opioid use disorder (OUD). One treatment strategy in patients with OUD is rotating from a short-acting opioid to a long-acting opioid (buprenorphine/naloxone (BuNa) or methadone). Both BuNa and methadone have been shown to be effective strategies in patients with OUD reducing opioid misuse, however data on head-to-head comparison in patients with chronic non-malignant pain and prescription OUD are limited.

METHODS

This two-armed open-label, randomized controlled trial aims to compare effectiveness between BuNa and methadone in patients with chronic non-malignant with prescription OUD (n = 100). Participants receive inpatient rotation to either BuNa or methadone with a flexible dosing regimen. The primary outcome is opioid misuse 2 months after rotation. Secondary outcomes include treatment compliance, side effects, analgesia, opioid craving, quality of life, mood symptoms, cognitive and physical functioning over 2- and 6 months follow-up. Linear mixed model analysis will be used to evaluate change in outcome parameters over time between the treatment arms.

DISCUSSION

This is one of the first studies comparing buprenorphine/naloxone and methadone for treating prescription OUD in a broad patient group with chronic non-malignant pain. Results may guide future treatment for patients with chronic pain and prescription OUD. Trial registration https://www.trialregister.nl/ , NL9781.

Buprenorphine Microdosing for the Pain and Palliative Care Clinician

Buprenorphine (BUP) can be a safe and effective alternative to traditional opioids for many patients with chronic pain. For patients on higher doses of opioids, rotation to BUP is complicated by the requirement of an opioid-free interval or withdrawal during the transition. Microdosing inductions, in which BUP is gradually titrated, while full agonist opioids are continued, are a viable alternative to traditional inductions. The objective of this article is to review the current literature on BUP microdosing induction, with a focus on patients using opioids for pain. A literature review of the PubMed database was performed in the United States on articles published from inception to May 2021. A total of 34 publications were included. The most commonly utilized microdosing strategy involved administering divided doses of sublingual (SL) products marketed for opioid use disorder treatment, with 25 (73.5%) articles reporting use of partial SL tablets or films (ranging from 1/8 to 1/2 of a 2 mg product) at some point during the induction. Transdermal patches, low-dose SL BUP available in Europe, intravenous BUP, and buccal BUP have also been used. Beyond the products used, the speed of the microinduction, setting, final BUP dosing, and management of concomitant full agonists vary widely in the literature. Microdosing regimens should be individualized based on local guidelines and patient-specific factors. Further studies comparing the safety and efficacy of different protocols are warranted.

Opioid Rotation to Methadone for Refractory Cancer Pain: A Case Series

Methadone has been increasingly used in the treatment of refractory cancer pain with different conversion methods and ratios described.A retrospective chart review of patients on methadone for cancer pain was conducted to assess its use as the primary opioid, focusing on pain characteristics, opioid rotation indication, previous analgesics, adverse effects and final methadone dose in comparison with the pre-rotation Morphine Equivalent Daily Dose (MEDD).Eight patients were rotated to methadone due to refractory moderate-severe cancer pain and achieved good pain relief. Three developed adverse effects (2 mild, 1 serious). None required withdrawal of methadone. The final methadone dose required varied significantly from predictions made based on equianalgesic conversion tables.Methadone is effective for the treatment of refractory cancer pain. The eventual required methadone doses for these patients were significantly different from predicted doses suggested by equianalgesic conversion tables and guidelines. This highlights the importance of individualized titration and careful clinical assessment during the rotation and in the days after, to prevent serious adverse effects.

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.

A review of common methods to convert morphine to methadone

When dosed appropriately on carefully chosen patients, methadone can be a very safe and effective choice in managing chronic pain. Many authors have discussed important issues surrounding patient selection, drug interactions, screening for QTc prolongation and monitoring. This article will focus on the dosing dilemma that exists after the patient is deemed an appropriate candidate for methadone and a conversion is necessary from another opioid. Despite many publications dedicated to addressing this challenging topic, there is no consensus on the most appropriate method for converting an opioid regimen to methadone. Given the lack of concrete guidance, clinicians in a community setting are likely to be faced with an increased challenge if there are no available pain specialists to provide clinical support. Common methods for converting morphine to methadone will be reviewed and two clinical patient scenarios used to illustrate the outcomes of applying the methods.