Methadone for Pain Management: Past, Present and Future

MOP-dependent enhancement of methadone on the effectiveness of ALA-PDT for A172 cells by upregulating phosphorylated JNK and BCL2

BACKGROUND

Methadone, as a long-acting opioid analgesic, shows an ability to sensitize the treatment of ALA-PDT for glioblastoma cells (A172) in vitro by promoting apoptosis. However, the mechanisms how methadone enhances the effectiveness of ALA-PDT for tumor cells remains to be clarified.

METHODS

The expression of mu opioid receptor (MOP), apoptosis, phosphorylated c-Jun N-terminal kinase (JNK) and phosphorylated apoptosis regulator B cell lymphoma 2 (BCL2) were measured by flow cytometry. Cytotoxicity was determined using Cell Counting Kit-8 (CCK-8). A MOP antagonist, naloxone, was used to evaluate the role of MOP in the above process.

RESULTS

It was found that A172 cells show the expression of MOP and that naloxone inhibits the enhancement of the methadone effect on apoptosis following ALA-PDT (p < 0.05). Phosphorylated JNK and BCL2 induced by ALA-PDT were promoted in the presence of methadone (p < 0.05). These methadone effects were also inhibited by naloxone (p < 0.05).

CONCLUSIONS

The results suggest that apoptosis induced by ALA-PDT is enhanced by methadone, mostly MOP-mediated, through the upregulation of accumulation of phosphorylated JNK and BCL2, leading to a promotion of cytotoxicity of ALA-PDT for A172 cells.

Methadone in Cancer Pain

Methadone has been an unique, versatile, cost effective, synthetic opioid utilized in nociceptive as well as neuropathic pain. Pain and palliative care physicians started accepting methadone in treatment of complex pain associated with advanced cancer and neuropathic pain syndromes in which conventional opioids were no longer effective. The challenge is in accepting methadone as a main stream first line opioid, from being considered as a second line replacement/substitution drug all these years. Methadone has a significant role as opioid rotation in refractory cancer pain, especially when started early leading to successful conversion. Advantages of methadone in paediatric patients with advanced cancer were its safety and efficacy as a first-choice opioid, availability as a liquid formulation and its infrequent dose requirements. Methadone is neither recommended nor justified to be used as an anti-cancer drug and its role as an anti-cancer agent is a misconception. Many guidelines were proposed after 2008 to address methadone safety. Most of them emphasized on prevention of cardiac arrhythmia and association of methadone with QTc prolongation rather than address the real issue. Methadone has been established to be safe when used in opioid naïve patients with careful titration instituted in an ambulatory setting and has equal success in opioid rotation in outpatient setup. Methadone prescription should be carried out by experienced pain and palliative care providers with careful dose titration and clinical monitoring.

Ethics of Opioid Prescriber Regulations: Physicians, Patients, and Pain

BACKGROUND

Opioid addiction affects patients of every race, sex, and socioeconomic status. Overprescribing is a known cause of the opioid crisis. Various agencies have implemented requirements and programs to combat practitioner overprescribing; however, there can be adverse ethical consequences when regulations are used to influence physician behavior. We aimed to explore the ethical aspects of some of these interventions.

METHODS

We reviewed various interventions for opioid prescribing through the lens of ethical inquiry. Specifically, we evaluated (1) requirements for educational programs for prescribers and patients, (2) prescription monitoring programs, (3) prescription limits, (4) development of condition-specific pain management guidelines, (5) increased utilization of naloxone, and (6) opioid disposal programs. We also evaluated patient satisfaction survey questions relating to pain.

RESULTS

The present analysis demonstrated that the following regulatory interventions are ethically sound: requirements for educational programs for prescribers and patients, robust prescription monitoring programs that cross state lines, increased prescribing of naloxone for at-risk patients, development of condition-specific pain management guidelines, improvement of opioid disposal programs, and elimination of pain-control questions from patient satisfaction surveys. However, implementation of strict prescribing limits without accommodation for procedure and patient characteristics may have negative ethical consequences.

CONCLUSIONS

Although the importance of addressing the current opioid crisis cannot be understated, as surgeons, we must examine ethical implications of any new regulations that affect musculoskeletal patient care.