Comparison between Preoperative Methadone and Buprenorphine Use on Postoperative Opioid Requirement: A Retrospective Cohort Study

A retrospective analysis of perioperative medications for opioid-use disorder and tapering additional postsurgical opioids via a transitional pain service

AIMS

To investigate perioperative opioid requirements in patients on methadone or buprenorphine as medication for opioid-use disorder (MOUD) who attended a transitional pain clinic (Personalized Pain Program, PPP).

METHODS

This retrospective cohort study assessed adults on MOUD with surgery and attendance at the Johns Hopkins PPP between 2017 and 2022. Daily non-MOUD opioid use over 6 time-points was evaluated with regression models controlling for days since surgery. The time to complete non-MOUD opioid taper was analysed by accelerated failure time and Kaplan-Meier models.

RESULTS

Fifty patients (28 on methadone, 22 on buprenorphine) were included with a median age of 44.3 years, 54% male, 62% Caucasian and 54% unemployed. MOUD inpatient administration occurred in 92.8% of patients on preoperative methadone but only in 36.3% of patients on preoperative buprenorphine. Non-MOUD opioid use decreased over time postoperatively (β = -0.54, P < .001) with a median decrease of 90 mg morphine equivalents (MME) between the first and last PPP visit, resulting in 46% tapered off by PPP completion. Older age and duration in PPP were associated with lower MME, while mental health conditions, longer hospital stays and higher discharge opioid prescriptions were associated with higher MME. The average time to non-MOUD opioid taper was 1.79× longer in patients on buprenorphine (P = .026), 2.75× in males (P = .023), 4.66× with mental health conditions (P < .001), 2.37× with chronic pain (P = .031) and 3.51× if on preoperative non-MOUD opioids; however, higher initial MOUD level decreased time to taper (P = .001).

CONCLUSIONS

Postoperative opioid tapering utilizing a transitional pain service is possible in patients on MOUD.

Post-operative pain control in patients on buprenorphine or methadone for opioid use disorder

OBJECTIVE

This study aimed to determine whether there is a difference in pain scores and opioid consumption after elective surgery in patients maintained on methadone or buprenorphine for opioid use disorder (OUD). Additionally, we investigated the impact of continuing or discontinuing methadone or buprenorphine on post-operative pain outcomes.

DESIGN

A single-center retrospective cohort study.

SETTING

Tertiary care medical center.

PATIENTS AND PARTICIPANTS

Adults aged 18 years or older with OUD maintained on buprenorphine or methadone who underwent elective surgery between January 1, 2017, and January 1, 2021.

INTERVENTIONS

Patients were identified through electronic medical records, and demographic and clinical data were collected.

MAIN OUTCOME MEASURES

The primary outcome was opioid consumption at 24 hours post-operatively, measured in milligram morphine equivalents. The secondary outcome was opioid consumption and pain scores up to 72 hours post-operatively, assessed using a numeric rating scale.

RESULTS

This study included 366 patients (64 percent on buprenorphine and 36 percent on methadone). Opioid utilization significantly increased when buprenorphine was not administered post-operatively. Both groups exhibited comparable total opioid consumption during the post-operative period. In the buprenorphine cohort, pain scores differed significantly based on the receipt of medications for OUD post-operatively.

CONCLUSIONS

This study reinforces existing evidence supporting the continuation of medications for opioid use disorder, specifically buprenorphine and methadone, during the perioperative period. Dissemination of guideline recommendations is essential to ensure optimal post-operative pain management for this patient population.

Effects of a Two-Month Exercise Training Program on Concurrent Non-Opiate Substance Use in Opioid-Dependent Patients during Substitution Treatment

BACKGROUND

This randomized controlled trial aimed to evaluate the effects of a two-month exercise intervention on the concurrent non-opiate substance use (alcohol, cocaine, cannabis, and benzodiazepines) in opioid users during their medication treatment.

METHODS

Ninety opioid users (41 females) in methadone and buprenorphine medication treatment were randomly divided into four groups: (a) buprenorphine experimental (BEX; n = 26, aged 41.9 ± 6.1 yrs); (b) buprenorphine control (BCON; n = 25, aged 41.9 ± 5.6 yrs); (c) methadone experimental (MEX; n = 20, aged 46.7 ± 6.6 yrs); and (d) methadone control (MCON; n = 19, aged 46.1 ± 7.5 yrs). The experimental groups (BEX and MEX) followed an aerobic exercise training program on a treadmill for 20 min at 70% HRmax, 3 days/week for 8 weeks. Socio-demographic, anthropometric, and clinical characteristics, as well as non-opioid drug use in days and quantity per week, were assessed before and after the intervention period.

RESULTS

Following the exercise training, the weekly non-opioid substance consumption (days) decreased (p < 0.05) in both exercise groups and was lower in BEX compared to MEX, while no differences were observed (p > 0.05) between the control groups (BCON vs. MCON) or compared to their baseline levels. Similarly, the daily amount of non-opiate substance intake was reduced (p < 0.05) post-training in BEX and MEX, whereas it did not differ (p > 0.05) in BCON and MCON compared to the baseline.

CONCLUSIONS

The two-month exercise intervention reduced the non-opioid drug use in both the methadone and buprenorphine substitution groups compared to the controls, suggesting that aerobic exercise training may be an effective strategy for treating patients with OUDs.

Endogenous opiates and behavior: 2022

This paper is the forty-fifth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2022 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Association Between Postoperative Methocarbamol and Postoperative Pain Opioid Dose Requirements: A Retrospective Cohort Study

OBJECTIVES

We tested the hypothesis that patients who received methocarbamol postoperatively experience less severe pain and require smaller doses of opioids than those who did not receive methocarbamol.

MATERIALS AND METHODS

This is a retrospective cohort study of patients undergoing surgery involving the musculoskeletal system. Of 9089 patients, 704 received methocarbamol during 48 hours postoperatively, while 8385 did not receive methocarbamol. The patients who received methocarbamol postoperatively and the patients who did not receive methocarbamol were compared on the time-weighted average (TWA) pain score and opioid dose requirements in morphine milligram equivalents (MME) during the first 48 hours postoperatively, using propensity score-weighted regression models to adjusting for preoperative and intraoperative covariates.

RESULTS

Postoperative 48-hour TWA pain scores were 5.5±1.7 (mean±SD), and 4.3±2.1 for methocarbamol and non-methocarbamol patients. Postoperative 48-hour opioid dose requirements in MME were 276 [170-347] (median [interquartile range (IQR)]) mg, and 190 [60-248] mg for methocarbamol and non-methocarbamol patients. In propensity score-weighted regression models, receiving methocarbamol postoperatively was associated with 0.97-point higher postoperative TWA pain score (95% CI, 0.83-1.11; P <0.001), and 93.6-MME higher postoperative opioid dose requirements (95% CI, 79.9 to 107.4; P <0.001), compared with not receiving methocarbamol postoperatively.

DISCUSSION

Postoperative methocarbamol was associated with significantly higher acute postoperative pain burden and opioid dose requirements. Although the results of the study are influenced by residual confounding, they suggest a limited-if any-benefit of methocarbamol as an adjunct of postoperative pain management.

Diels-Alder Adducts of Morphinan-6,8-Dienes and Their Transformations

6,14-ethenomorphinans are semisynthetic opiate derivatives containing an ethylene bridge between positions 6 and 14 in ring-C of the morphine skeleton that imparts a rigid molecular structure. These compounds represent an important family of opioid receptor ligands in which the 6,14-etheno bridged structural motif originates from a [4 + 2] cycloaddition of morphinan-6,8-dienes with dienophiles. Certain 6,14-ethenomorphinans having extremely high affinity for opioid receptors are often non-selective for opioid receptor subtypes, but this view is now undergoing some revision. The agonist 20R-etorphine and 20R-dihydroetorphine are several thousand times more potent analgesics than morphine, whereas diprenorphine is a high-affinity non-selective antagonist. The partial agonist buprenorphine is used as an analgesic in the management of post-operative pain or in substitution therapy for opiate addiction, sometimes in combination with the non-selective antagonist naloxone. In the context of the current opioid crisis, we communicated a summary of several decades of work toward generating opioid analgesics with lesser side effects or abuse potential. Our summary placed a focus on Diels-Alder reactions of morphinan-6,8-dienes and subsequent transformations of the cycloadducts. We also summarized the pharmacological aspects of radiolabeled 6,14-ethenomorphinans used in molecular imaging of opioid receptors.