Use of methadone as an alternative to morphine for chronic pain management: a noninferiority retrospective observational study

Intraoperative Methadone Use Is Associated With Reduced Postoperative Pain and More Rapid Opioid Weaning After Coronary Artery Bypass Grafting

OBJECTIVE

To explore the association between intraoperative methadone use, postoperative pain, and opioid consumption after coronary artery bypass grafting (CABG) surgery.

DESIGN

Retrospective cohort study.

SETTING

Single academic medical center.

PARTICIPANTS

Patients undergoing isolated CABG over a 5-year period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic data, comorbidities, and intraoperative anesthetic medications were recorded. Primary study outcomes were average and maximum pain scores and morphine milligram equivalent consumption on the first 2 postoperative days (PODs). Linear mixed-effects regression models were used to examine the effect of intraoperative methadone use on study outcomes. Among 1,338 patients, 78.6% received intraoperative methadone (0.2 mg/kg). Patients who did not receive methadone had higher average (estimated [Est], 0.48; 95% confidence interval [CI], 0.22-0.73; p < 0.001) and maximum postoperative (Est, 0.49; 95% CI, 0.23-0.75; p < 0.001) pain scores over PODs 0 to 2. For postoperative opioid consumption, there was a significant intraoperative methadone use-time interaction effect on postoperative opioid use (odds ratio [OR], 2.21; 95% CI, 1.74-2.80; p < 0.001). Across PODs 0 to 2, patients who received intraoperative methadone had a faster decline in postoperative opioid use than those who did not receive intraoperative methadone. Patients who did not receive intraoperative methadone were extubated slightly faster (OR, 0.82; 95% CI, 0.72-0.93; p < 0.01).

CONCLUSIONS

Our data suggest that the use of intraoperative methadone is safe, reduces postoperative pain, and expedites weaning from postoperative opioids after CABG surgery.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Chemical similarity of molecules with physiological response

Measuring the similarity among molecules is an important task in various chemically oriented problems. This elusive concept is hard to define and quantify. Moreover, the complexity of the problem is elevated by bifurcating the notion of molecular similarity to structural and chemical similarity. While the structural similarity of molecules is being extensively researched, the so-called chemical similarity is being mentioned scarcely. Here, we propose a way of converting the physico-chemical properties into molecular fingerprints. Then, using the apparatus of measuring the structural similarity, the chemical similarity can be assessed. The proof of a concept is demonstrated on a set of molecules that induce diverse physiological responses.

Pro-Con Debate: Role of Methadone in Enhanced Recovery After Surgery Protocols-Superior Analgesic or Harmful Drug?

Enhanced recovery after surgery (ERAS) protocols are standardized and designed to provide superior analgesia, reduce opioid consumption, improve patient recovery, and reduce hospital length of stay. Yet, moderate-to-severe postsurgical pain continues to afflict over 40% of patients and remains a major priority for anesthesia research. Methadone administration in the perioperative setting may reduce postoperative pain scores and have opioid-sparing effects, which may be beneficial for enhanced recovery. Methadone possesses a multimodal profile consisting of µ-opioid agonism, N-methyl-d-aspartate (NMDA) receptor antagonism, and reuptake inhibition of serotonin and norepinephrine. Furthermore, it may attenuate the development of chronic postsurgical pain. However, caution is advised with perioperative use of methadone in specific high-risk patient populations and surgical settings. Methadone's wide pharmacokinetic variability, opioid-related adverse effects, and potential negative impact on cost-effectiveness may also limit its use in the perioperative setting. In this PRO-CON commentary article, the authors debate whether methadone should be incorporated in ERAS protocols to provide superior analgesia with no increased risks.