Opioid Induced Hyperalgesia

Occurrence rate and risk factors for rest and procedural pain in critically ill patients: A systematic review and meta-analysis

OBJECTIVES

To summarize the occurrence rates and identified the risk factors for pain at rest and during procedures in critically ill patients.

METHODS

This study conducted a systematic review and meta-analysis. The Embase, PubMed, CINAHL Plus, Web of Science Core Collection and ProQuest Dissertations & Theses A&I databases were searched from inception to January 10, 2025, for relevant studies. Two independent researchers screened the articles, reviewed them, and extracted data. The data were analyzed using a random-effects model.

RESULTS

This meta-analysis included 23 observational studies with prospective, retrospective, and cross-sectional study designs encompassing 8,073 adult participants. The pooled occurrence rate of pain at rest among critically ill patients was 41 % (95 % confidence interval [CI] = 0.27 to 0.57), whereas that of pain during procedures was 68.4 % (95 % CI = 0.58 to 0.77). Most studies on intensive care unit (ICU)-related pain were conducted in the Asia Pacific region, the Americas, and Western Europe. Age was determined to be negatively associated with pain at rest, whereas opioid use percentage and percentage of male were positively associated with the occurrence of pain during procedures.

CONCLUSIONS

Pain at rest and during procedures is highly prevalent and often undertreated in ICU patients. Health-care providers should develop and implement effective pain management strategies to mitigate both pain at rest and procedural pain in critically ill patients.

IMPLICATIONS FOR CLINICAL PRACTICE

Pain is a frequent and troubling experience for patients in the ICU, so healthcare providers need to assess and address it regularly. This study also pinpointed specific factors linked to pain at rest and during procedures, some of which can be changed or managed. These results offer ICU medical team valuable insights for identifying high-risk patients and delivering personalized interventions to minimize pain.

Utilizing Dexmedetomidine for Opioid-Resistant Pain and Anxiety in the Palliative Care Unit: A Case Report on Efficacy, Withdrawal Challenges, and Protocol Adaptations

Dexmedetomidine (Precedex™) has proved useful in palliating anxiety and intractable pain in patients at the end of life. However, abrupt cessation can precipitate withdrawal, which is highly unpleasant and potentially dangerous. Here, we present the case of a patient whose intractable pain was successfully palliated with a dexmedetomidine infusion but who then developed severe withdrawal when the infusion was stopped with a change in her plan of care. We present a review of the literature around transitioning patients off dexmedetomidine and highlight the need for more guidance on nonintensive care unit management of its side effects and alternatives.

A Prospective Cohort Study to Determine Which Opioid-Naïve Emergency Department Patients Are at Risk of Persistent Opioid Use

STUDY OBJECTIVE

It is unclear which opioid-naïve emergency department (ED) patients prescribed an opioid progress to opioid use disorder. We tested the hypothesis that opioid-induced euphoria and persistent pain 2 weeks after an ED visit would be associated with persistent prescribed opioid use among opioid-naïve ED patients who presented to the ED with pain and were discharged with an opioid prescription.

METHODS

This was a prospective cohort study. We enrolled patients during an ED visit and followed them by telephone 48 hours, 2 weeks, and 6 months later. We also reviewed the state prescription monitoring database at 6 months. Persistent opioid use was defined as ≥1 opioid prescription/month after ED discharge. At 48 hours, participants were asked: How much euphoria, joy, or happiness did the opioid medication give you? and how much would you like to use the medication again? Each of these was assessed on a 0 to 10 scale. Pain was measured with a 4-item ordinal scale: severe, moderate, mild, or none.

RESULTS

A total of 699 patients were eligible for participation and enrolled. Of these, 17/699 (2%) developed new-onset persistent opioid use. Median feeling euphoria, joy, or happiness was 0 (interquartile range [IQR]: 0, 0); median like to use again was 6 (IQR: 0, 10). A total of 296/256 (45%) reported moderate or severe pain in the affected area at 2 weeks. Neither euphoria/joy/happiness (odds ratio [OR] 0.84, 95% confidence interval [CI] 0.61 to 1.15) nor take again (OR 1.06, 95% CI 0.92 to 1.21) was associated with persistent opioid use. Moderate or severe pain was associated with persistent opioid use (OR 5.15, 95% CI 1.43 to 18.50).

CONCLUSION

Persistence of pain 2 weeks later but not opioid-induced euphoria is associated with progression to persistent prescribed opioid use. If validated, these data would allow an integrated health care system to identify patients at risk of progression.

Opioid-free versus opioid-based anesthesia in laparoscopic sleeve gastrectomy: a single-center, randomized, controlled trial

BACKGROUND

Opioids are commonly used in general anesthesia for pain management. However, they are linked to significant side effects. Patients undergoing laparoscopic sleeve gastrectomy, particularly those with obesity, are at higher risk of experiencing adverse effects associated with opioids. Therefore, there is a need to explore alternative anesthesia options that do not rely on opioids. This study aims to investigate the efficacy of opioid-free anesthesia (OFA) compared to traditional opioid-based anesthesia (OBA) in patients undergoing laparoscopic sleeve gastrectomy.

METHODS

This single-center randomized controlled trial included eighty-three patients undergoing laparoscopic sleeve gastrectomy in a tertiary hospital. Patients were randomly assigned to dexmedetomidine and lidocaine infusion (OFA) or remifentanil (OBA). All patients received intra-operative propofol, sevoflurane, a neuromuscular blocking agent, and ketamine. The primary outcome included opioid consumption during the post-anesthesia care unit (PACU). Secondary measures included intraoperative hemodynamic stability, time to extubation, PACU stay duration, opioid consumption during the first 48 h, and anti-emetic requirements. Independent samples t-test or Mann-Whitney U test was used to assess for differences across the two groups.

RESULTS

PACU morphine consumption, total postoperative morphine consumption, anti-emetic requirements up to 48 h after surgery, and pain levels after surgery were not statistically significantly different between OFA and OBA groups. Other variables were not statistically different between the two groups, except for intraoperative anti-hypertensives where more patients in the OFA groups required it.

CONCLUSIONS

Opioid-free anesthesia hasn't shown an opioid-sparing effect in patients with obesity undergoing laparoscopic sleeve gastrectomy. Larger multi-center studies are required to fully establish its effectiveness.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03507634); first trial registration date: 12/04/2018; first posted date: 25/04/2018.

Opioidergic tuning of social attachment: reciprocal relationship between social deprivation and opioid abuse

Individuals misusing opioids often report heightened feelings of loneliness and decreased ability to maintain social connections. This disruption in social functioning further promotes addiction, creating a cycle in which increasing isolation drives drug use. Social factors also appear to impact susceptibility and progression of opioid dependence. In particular, increasing evidence suggests that poor early social bond formation and social environments may increase the risk of opioid abuse later in life. The brain opioid theory of social attachment suggests that endogenous opioids are key to forming and sustaining social bonds. Growing literature describes the opioid system as a powerful modulator of social separation distress and attachment formation in rodents and primates. In this framework, disruptions in opioidergic signaling due to opioid abuse may mediate social reward processing and behavior. While changes in endogenous opioid peptides and receptors have been reported in these early-life adversity models, the underlying mechanisms remain poorly understood. This review addresses the apparent bidirectional causal relationship between social deprivation and opioid addiction susceptibility, investigating the role of opioid transmission in attachment bond formation and prosocial behavior. We propose that early social deprivation disrupts the neurobiological substrates associated with opioid transmission, leading to deficits in social attachment and reinforcing addictive behaviors. By examining the literature, we discuss potential overlapping neural pathways between social isolation and opioid addiction, focusing on major reward-aversion substrates known to respond to opioids.

Geriatric dermatologic surgery part II: Peri- and intraoperative considerations in the geriatric dermatologic surgery patient

Geriatric patients compose a growing proportion of the dermatologic surgical population. Dermatologists and dermatologic surgeons should be cognizant of the unique physiologic considerations that accompany this group to deliver highly effective care. The purpose of this article is to discuss the unique preoperative, intraoperative, and postoperative considerations geriatric patients present with to provide goal-concordant care. Preoperative considerations include medication optimization and anxiolysis. Intraoperative considerations such as fall risk assessment and prevention, sundowning, familial support, and pharmacologic interactions will be discussed. Lastly, effective methods for optimizing postoperative wound care, home care, and follow-up are reviewed.

Pharmacological interventions for remifentanil-induced hyperalgesia: A systematic review and network meta-analysis of preclinical trials

BACKGROUND

To improve perioperative pain management, several interventions have been suggested for the prevention of increased pain sensitivity caused by opioids (called opioid-induced hyperalgesia). It is currently unclear which intervention is the most effective or appropriate in preventing opioid-induced hyperalgesia. Remifentanil is the most investigated opioid causing opioid-induced hyperalgesia. Thus, to guide future research, we conducted a systematic review and a network meta-analysis of preclinical trials investigating pharmacological interventions for remifentanil-induced hyperalgesia.

METHODS

To identify relevant articles, electronic database searches were conducted in Embase, PubMed, Web of Science, and Google Scholar. Study characteristics were extracted, and the risk of bias was evaluated. Studies were included in the network meta-analysis if they shared similar characteristics with at least one other study. The interventions were ranked based on P-scores.

RESULTS

Overall, the 62 eligible trials tested 86 individual interventions and 6 combination interventions. Thirty-five studies eligible in the network meta-analysis formed five groups which were further divided into subgroups based on the quantitative sensory tests used. The best-ranked interventions within the subgroups were Anxa12-26, MRS2179, salicylaldehyde isonicotinoyl hydrazone (SIH), ANA-12, TDZD-8, ketamine, dexmedetomidine, JWH015, and the combination of KN93 and ketamine.

DISCUSSION

The current literature is too heterogeneous to produce a clear answer on which intervention is the most effective in preventing remifentanil-induced hyperalgesia. Future research in this field should prioritise finding the most effective intervention over testing the efficacy of new options. The results of our work can be used in planning which comparisons should be included in new trials.

The relationship of pain intensity and opioid craving with delayed methadone dose: A preliminary study of individuals with opioid use disorder

AIMS

Despite a strong theoretical link between opioid craving and pain, little is known about the temporal relationship between pain and craving and the acute experience of pain in the context of methadone treatment. Using a cross-over design, the current study evaluated the time course of pain and craving and objective experience of pain as a function of the last methadone dose.

METHODS

Participants (n = 20) presented for the study in the morning and either received methadone dose as scheduled or delayed dose until the afternoon. During the 4-h study visit, participants completed a series of tasks, including repeated assessment of pain and craving at 0, +40, +70, +130, +160 and +240 min and a cold pressor test (CPT) at +15 and +220 min.

RESULTS

Separate mixed model results demonstrated no effect of dosing condition on craving; however, there was a significant dosing condition by time interaction (F(5,209) = 3.38, P = .006) such that pain increased over time in the delayed methadone condition but decreased in time in the scheduled methadone condition. A mixed model predicting self-reported pain revealed a three-way interaction between dosing condition, craving and time (F(5,197) = 2.39, P = .039) explained by a positive association between craving and pain at each time point (except 240 min) in delayed condition (P-range = .004-.0001). A separate mixed model on CPT data indicated a significant condition by time interaction such that pain threshold decreased in the delayed, but not scheduled, condition (F(1,57) = 4.01, P = .050).

CONCLUSIONS

These preliminary findings highlight the potential for increased risks after even a short delay in receiving a methadone dose.

Assessment of Surgical Complications Strengthen the Relationship Between Spine Surgery Procedure Intensity and Chronic Opioid Use After Surgery

STUDY DESIGN

Prospective cohort using routinely collected health data.

OBJECTIVE

To compare opioid use based on surgery intensity (low or high).

SUMMARY OF BACKGROUND DATA

Many factors influence an individual's experience of pain. The extent to which postsurgical opioid use is influenced by the severity of spine surgery is unknown.

METHODS

The participants were individuals undergoing spine surgery in a large military hospital. Procedures were categorized as low intensity (eg, microdiscectomy and laminectomy) and high intensity (eg, fusion and arthroplasty). The Surgical Scheduling System and Military Health System Data Repository were queried for healthcare utilization the 1 year before and after surgery. We compared opioid use after surgery between groups, adjusting for prior opioid use and surgical complications.

RESULTS

A total of 342 individuals met the inclusion criteria, with mean age 45.4 years (SD 10.9), and 33.0% were women. Of these, 221 (64.6%) underwent a low-intensity procedure and 121 (35.4%) underwent a high-intensity procedure. Mean postoperative opioid prescription fills were greater in the high- versus low-intensity group (9.0 vs. 5.7; P <0.001), as were the mean total days' supply (158.9 vs. 81.8; P <0.001). Median morphine milligram equivalents (MMEs) were not significantly different (40.2 vs. 42.7; P =0.287). Of the cohort, 26.3% were chronic opioid users after surgery. Adjusted rates of long-term opioid use were not different between groups when only accounting for prior opioid use but significantly higher for the high-intensity group when adjusting for surgical complications (OR=2.08; 95% CI 1.09-3.97). Of the entire cohort, 52.5% was still filling opioid prescriptions after 6 months.

CONCLUSIONS

Higher-intensity procedures were associated with greater postoperative opioid use than lower-intensity procedures. Chronic opioid use was not significantly different between surgical intensity groups when considering only prior opioid use. Chronic opioid use was significantly higher among higher intensity procedures when accounting for surgical complications. The presence of surgical complications is a stronger predictor of postsurgical long-term opioid use in high-intensity surgeries than history of opioid use alone.

LEVEL OF EVIDENCE

Level III.

The use of music in the treatment of chronic pain: a scoping review

OBJECTIVE

Music is a promising strategy to address the physical, psychological, and social needs of people with chronic pain. To better understand its potential in the treatment of chronic pain, this study aims to assess the state of knowledge regarding the effects of music in the context of chronic pain treatment.

METHODS

A scoping review was conducted in eight databases using music, chronic pain, and treatment concepts and associated keywords. Studies were included in the review if they reported some effects of any form of music on chronic pain or concomitant conditions.

RESULTS

Sixty-three studies were identified. Results showed numerous benefits of music-based interventions on chronic pain and common concomitant difficulties including emotional regulation, anxiety and depression symptoms, and social issues. Though literature supports varied forms of music-based interventions, those that account for participants' preferences and that encourage self-management and autonomy appeared to be the most effective.

CONCLUSIONS

Despite the benefits of music in the management of pain and concomitant difficulties, there remain few examples of applied music interventions in services designed for people who experience chronic pain. More research is needed to identify the musical modalities that would be the most adapted and effective to complement chronic pain services.

"Everybody looks at it as drug use instead of pain management": Experiences of chronic pain and its management among older people living with HIV who use drugs in Vancouver, British Columbia

BACKGROUND

Chronic pain is a common comorbidity among people living with HIV (PLHIV) who use drugs. However, in-depth understanding of how chronic pain is managed among PLHIV who use drugs remains limited, especially in the aging population. We sought to explore how older PLHIV who use drugs manage chronic pain and situate these experiences within their social and structural contexts.

METHODS

This study draws on semi-structured, in-depth interviews conducted with 27 PLHIV who use drugs and were living with chronic pain in Vancouver, Canada. Participants were recruited through outreach at an integrated HIV care facility and from an open prospective cohort study of PLHIV who use drugs. Interviews were audio-recorded, transcribed, and coded. Salient themes were identified using an inductive-deductive approach to coding.

RESULTS

Three themes emerged from our data analysis. First, chronic pain influenced daily life and functioning, including ability to manage HIV and other health conditions. Second, provider-related barriers, including anti-drug stigma and discrimination, impeded access to pain management. Third, illicit drugs were often used to self-manage pain.

CONCLUSIONS

This study advances our understanding of the everyday experiences of living with chronic pain among older PLHIV who use drugs. Inadequately managed pain may contribute to an array of health- and drug-related harms among this population. Our findings underscore the need for equitable access to pain care, and safer alternatives to the toxic illicit drug supply in the context of the illicit drug poisoning epidemic, to relieve suffering and improve quality of life for older PLHIV who use drugs.

Disrupted Circadian Rhythms and Substance Use Disorders: A Narrative Review

Substance use disorder is a major global health concern, with a high prevalence among adolescents and young adults. The most common substances of abuse include alcohol, marijuana, cocaine, nicotine, and opiates. Evidence suggests that a mismatch between contemporary lifestyle and environmental demands leads to disrupted circadian rhythms that impair optimal physiological and behavioral function, which can increase the vulnerability to develop substance use disorder and related problems. The circadian system plays an important role in regulating the sleep-wake cycle and reward processing, both of which directly affect substance abuse. Distorted substance use can have a reciprocal effect on the circadian system by influencing circadian clock gene expression. Considering the detrimental health consequences and profound societal impact of substance use disorder, it is crucial to comprehend its complex association with circadian rhythms, which can pave the way for the generation of novel chronotherapeutic treatment approaches. In this narrative review, we have explored the potential contributions of disrupted circadian rhythms and sleep on use and relapse of different substances of abuse. The involvement of circadian clock genes with drug reward pathways is discussed, along with the potential research areas that can be explored to minimize disordered substance use by improving circadian hygiene.

Opioid-free versus opioid-based anesthesia in major spine surgery: a prospective, randomized, controlled clinical trial

BACKGROUND

Major spine surgery is associated with severe postoperative pain and increased opioid consumption. Opioid-free anesthesia (OFA) is thought to provide adequate intraoperative analgesia with reduced postoperative opioid consumption. The aim of this study is to compare the impact of intraoperative OFA approach to the conventional opioid-based anesthesia (OBA) on postoperative pain, opioid consumption, and related side effects in patients undergoing multilevel spinal fusion surgery.

METHODS

Forty-eight patients undergoing elective major spine surgery were randomly allocated to either receive intraoperative dexmedetomidine and lidocaine (OFA group) or fentanyl during induction and intraoperative remifentanil (OBA group). All patients received intraoperative sevoflurane, propofol, rocuronium, ketamine, dexamethasone, ondansetron and postoperative paracetamol and patient-controlled analgesia device set to deliver intravenous morphine for 48 hours after surgery. Postoperative pain was measured using numerical rating scale. Opioid side effects were documented, when present.

RESULTS

OFA group required less morphine in the first 24 hours post-surgery (17.28±12.25 mg versus 27.96±19.75 mg, P<0.05). The incidence of postoperative nausea and vomiting (PONV) was significantly lower in the OFA group. More patients in the OFA group required antihypertensive medications compared to patients in the OBA group (P<0.05). In the post anesthesia care unit, OFA patients had a significantly longer stay than OBA patients (114.1±49.33 min versus 89.96±30.71 min, P<0.05).

CONCLUSIONS

OFA can be an alternative to OBA in patients undergoing multilevel spine fusion surgery. OFA reduces opioids consumption in the first 24 hours and PONV.

Functional ultrasound imaging of the human spinal cord

Utilizing the first in-human functional ultrasound imaging (fUSI) of the spinal cord, we demonstrate the integration of spinal functional responses to electrical stimulation. We record and characterize the hemodynamic responses of the spinal cord to a neuromodulatory intervention commonly used for treating pain and increasingly used for the restoration of sensorimotor and autonomic function. We found that the hemodynamic response to stimulation reflects a spatiotemporal modulation of the spinal cord circuitry not previously recognized. Our analytical capability offers a mechanism to assess blood flow changes with a new level of spatial and temporal precision in vivo and demonstrates that fUSI can decode the functional state of spinal networks in a single trial, which is of fundamental importance for developing real-time closed-loop neuromodulation systems. This work is a critical step toward developing a vital technique to study spinal cord function and effects of clinical neuromodulation.

Buprenorphine Facilitates Rapid Weaning From Very-High-Dose Intrathecal Hydromorphone

Pain management in patients on chronic opioid therapy is a common clinical challenge. The phenomena of opioid-induced hyperalgesia and tolerance are important contributors to that challenge. There are multiple strategies described to wean opioid doses and/or transition patients off opioids altogether. However, there is very little data to guide transitions off chronic intrathecal opioids. Here, we report on two patients with intractable post-laminectomy pain syndrome, resulting in severe functional limitation in the setting of opioid escalation culminating in the intrathecal delivery of hydromorphone to daily doses as high as 20 mg/day. We describe their rapid successful weaning off opioids using low-dose buprenorphine, which resulted in a dramatic improvement in pain and function.

Nociceptive Flexion Reflex Threshold is No Suitable Marker for Diagnosing Opioid-Induced Hyperalgesia

Background

Opioid induced hyperalgesia (OIH) describes a state of altered pain sensation due to opioid exposure. It often occurs among persons with opioid use disorder receiving substitution therapy.

Methods

The purpose of this study was to find out, whether OIH diagnosis could be facilitated by an objective pain indicating marker: the Nociceptive Flexion Reflex (NFR). Forty persons with opioid use disorder, 20 of them maintained on methadone and 20 treated with buprenorphine, as well as a control group of 20 opioid-free subjects, were examined. It was aimed to find out whether and in which way these opioid agonists alter reflex threshold (NFR-T). A cold-pressor test was performed to investigate the prevalence of OIH. Furthermore, electrical stimulation and electromyography analyzation were used for NFR-T measurement. Subjective pain ratings were evaluated with a numeric rating scale.

Results

Significantly increased sensitivity to cold pressor pain was found in both maintenance groups when compared to their opioid-free counterparts (p < 0.001). Neither methadone nor buprenorphine showed any effect on NFR-T. This might be explained by the reflex approaching at the wrong location in the central nervous system. Consequently, NFR-T is not a suitable marker for diagnosing OIH.

Conclusion

Although methadone and buprenorphine have been proven to cause OIH, no effect on NFR-T was observed. A statistically significant effect could have been observed with a larger number of participants. Further research, with special focus on patients' adjuvant medication, should be conducted in the future, to facilitate diagnosis of OIH and provide appropriate pain management for maintenance patients.

Problems with opioids - beyond misuse

The U.S. is grappling with an opioid epidemic, with millions of adults on long-term opioid therapy (LTOT). Although patients often report pain relief and improved daily function with opioids, research shows no significant differences in short-term outcomes between opioid and non-opioid users, as well as no long-term opioid benefits. This scoping review aims to identify lesser-known side effects of long-term opioid use and increase awareness of them, allowing healthcare providers and patients to better assess the risks and benefits of opioid use. Our data search from PubMed and Google Scholar used keywords related to opioids, chronic pain, hypogonadism, endocrinopathies, cancer progression, cardiovascular events, renovascular events, sleep disturbances, mood disorders and others, narrowing down to English-language full articles published from January 2018 to April 2023. This review emphasizes the probable serious adverse consequences of long-term opioid use on various body systems in patients with chronic pain. Given the lack of long-term benefits and significant adverse effects, our review underscores the critical need for healthcare providers to include these risks in discussions with patients when considering the long-term use of opioid therapy.

Morphine acts in vitro to directly prime nociceptors

Hyperalgesic priming is a preclinical model of the transition from acute to chronic pain characterized by a leftward shift in the dose-response curve for and marked prolongation of prostaglandin E2 (PGE2)-induced mechanical hyperalgesia, in vivo. In vitro, priming in nociceptors is characterized by a leftward shift in the concentration dependence for PGE2-induced nociceptor sensitization. In the present in vitro study we tested the hypothesis that a mu-opioid receptor (MOR) agonist opioid analgesic, morphine, can produce priming by its direct action on nociceptors. We report that treatment of nociceptors with morphine, in vitro, produces a leftward shift in the concentration dependence for PGE2-induced nociceptor sensitization. Our findings support the suggestion that opioids act directly on nociceptors to induce priming.

Projections from infralimbic medial prefrontal cortex glutamatergic outputs to amygdala mediates opioid induced hyperalgesia in male rats

Repeated use of opioid analgesics may cause a paradoxically exacerbated pain known as opioid-induced hyperalgesia (OIH), which hinders effective clinical intervention for severe pain. Currently, little is known about the neural circuits underlying OIH modulation. Previous studies suggest that laterocapsular division of the central nucleus of amygdala (CeLC) is critically involved in the regulation of OIH. Our purpose is to clarify the role of the projections from infralimbic medial prefrontal cortex (IL) to CeLC in OIH. We first produced an OIH model by repeated fentanyl subcutaneous injection in male rats. Immunofluorescence staining revealed that c-Fos-positive neurons were significantly increased in the right CeLC in OIH rats than the saline controls. Then, we used calcium/calmodulin-dependent protein kinase IIα (CaMKIIα) labeling and the patch-clamp recordings with ex vivo optogenetics to detect the functional projections from glutamate pyramidal neurons in IL to the CeLC. The synaptic transmission from IL to CeLC, shown in the excitatory postsynaptic currents (eEPSCs), inhibitory postsynaptic currents (eIPSCs) and paired-pulse ratio (PPR), was observably enhanced after fentanyl administration. Moreover, optogenetic activation of this IL-CeLC pathway decreased c-Fos expression in CeLC and ameliorated mechanical and thermal pain in OIH. On the contrary, silencing this pathway by chemogenetics exacerbated OIH by activating the CeLC. Combined with the electrophysiology results, the enhanced synaptic transmission from IL to CeLC might be a cortical gain of IL to relieve OIH rather than a reason for OIH generation. Scaling up IL outputs to CeLC may be an effective neuromodulation strategy to treat OIH.

The efficacy and safety of opioid-free anesthesia combined with ultrasound-guided intermediate cervical plexus block vs. opioid-based anesthesia in thyroid surgery-a randomized controlled trial

PURPOSE

In the context of the current comfort medicine and enhanced recovery after surgery, there is a demand for a new anesthesia method to reduce adverse reactions and accelerate recovery after surgery. This randomized controlled trial aimed to compare the efficacy and safety between opioid-free anesthesia (OFA) combined with ultrasound-guided intermediate cervical plexus block (ICPB) and opioid-based anesthesia in patients after thyroid surgery.

METHODS

In this study, 75 patients scheduled for thyroid surgery under general anesthesia were randomly allocated into two groups. The primary outcome included the incidence of nausea within 24 h after surgery. The main secondary outcomes included the incidence of vomiting and the visual analog score (VAS) scores within 24 h after surgery as well as the quality of recovery 40 questionnaires (QoR-40) scores 24 h after surgery.

RESULTS

In the OFA group, the incidence of postoperative nausea was 6.1%, compared to 39.4% in the control group (p = 0.001). No patient presented with postoperative vomiting in the OFA group, while 15.2% of patients suffered from postoperative vomiting in the control group (p = 0.063). The VAS scores of patients in the postanesthetic care unit (PACU) and 2 h, 4 h, and 6 h after surgery were lower in the OFA group, and the difference is statistically significant. Besides, the VAS scores of patients at rest (p = 1.000) and during swallowing (p = 1.000) 24 h after surgery were comparable.

CONCLUSION

Compared with opioid-based anesthesia, the OFA combined with the ultrasound-guided ICPB can better improve patients' postoperative recovery, reduce nausea, and decrease pain scores.

TRIAL REGISTRATION

Chinese Clinical Trial Regisrty, ChiCTR2200056344, https://www.chictr.org.cn.

Feasibility and preliminary efficacy of the Balance Program to reduce pain-related disability in pediatric sickle cell disease

BACKGROUND

Sickle cell disease (SCD) pain is associated with functional impairment, and treatment is often limited to pharmacological approaches with unwanted side effects. Although behavioral interventions exist for non-SCD pain populations, interventions designed to address pain-related impairment in SCD are lacking.

METHODS

Twenty youth (9-17 years) with SCD completed a four-week telemedicine pain intervention (NCT04388241). Participants and caregivers completed baseline and post-intervention PROMIS pain measures and the Treatment Evaluation Inventory-Short Form (TEI-SF). Descriptive analyses assessed feasibility and acceptability. Reliable Change Index analyses assessed for significant post-intervention changes in pain functioning. Paired t test analyses compared baseline and post-intervention opioid prescription fills.

RESULTS

All participants completed at least one treatment session. Eighteen (90%) youth completed all sessions. Youth (100%) and caregivers (94%) rated the intervention as moderately or highly acceptable on the TEI-SF. Forty-seven percent of caregivers and 44% of youth reported reliably significant improvements in pain interference after the intervention (median T-score differences: 24.8 and 23.5, respectively). Sixty-five percent of caregivers (T-score improvement difference: 19.3) and 31% of youth (T-score improvement difference: 32) reported improvements in pain behaviors. There was no significant difference in opioid prescription fills pre- and post-intervention (P > 0.05).

CONCLUSIONS

The Balance Program is feasible, highly acceptable, and can be delivered remotely to reduce barriers to care. Approximately half of youth and caregivers reported significant declines in pain interference following the intervention, with substantial improvements in functioning for treatment responders. Behavioral pain interventions are important adjunctive treatments to uniquely address functional impairment associated with acute and chronic pain in SCD.

The use of ketamine infusion to dramatically reduce opioid requirements in a patient whose high-dose intrathecal opioid pump was inadvertently cut during surgery

BACKGROUND

Chronic opioid therapy may lead to high level tolerance development, hyperalgesia, and central sensitization, which further complicates long-term therapeutic management of chronic pain patients. In this case, we encounter a patient who was receiving over 15,000 morphine milligram equivalents through their intrathecal pain pump. Unfortunately, the intrathecal pump was inadvertently cut during a spinal surgery. It was deemed unsafe to delivery IV equivalent opioid therapy in this case; instead, the patient was admitted to the ICU and given a four-day ketamine infusion.

METHOD

The patient was started on a ketamine infusion at a rate of 0.5mg/kg/h, which was continued for three days. On the fourth day, the infusion rate was tapered over 12 h before being completely stopped. No coinciding opioid therapy was given during this time, which was only restarted in the outpatient setting.

RESULTS

Despite chronic high levels of opioid therapy immediately prior to the ketamine infusion, the patient did not experience florid withdrawals during the infusion period. Additionally, the patient experienced remarkable improvement in their subjective pain rating, which decreased from 9 to 3-4 on an 11-point Number Rating Scale, while simultaneously being managed on an MME <100. These results were sustained through a 6-month follow-up period.

CONCLUSION

Ketamine may play an important role in attenuating not only tolerance but also acute withdrawal in a setting where rapid or instant weaning from high dose chronic opioid therapy is needed.

Can Electroacupuncture Be Useful in Opioid-Induced Hyperalgesia? A Case Report

Opioid-induced hyperalgesia (OIH) is characterized by a paradoxical increase in pain sensitivity following opioid exposure. Although animal models indicate that electroacupuncture (EA) is effective against pain sensitization, there are no reports of its clinical application in OIH treatment. This case report involves an adult patient with osteomalacia complicated by multiple vertebral fragility fractures. The patient developed OIH following the use of oxycodone to treat severe disabling lower back pain that was refractory to nonsteroidal anti-inflammatory drugs. After hospitalization and treatment with low EA-frequency (2-10 Hz) sessions, the patient exhibited significant pain reduction and functional recovery after the first session, which was accompanied by steady progressive improvement as the treatment continued. This case report illustrates the clinical efficacy of EA in OIH treatment and indicates that EA, which has multiple modes of action on the neurobiology of chronic pain, has potential applications in the management of complex and difficult-to-manage conditions, such as OIH.

Toll-like receptor 4 signaling pathway in sensory neurons mediates remifentanil-induced postoperative hyperalgesia via transient receptor potential ankyrin 1

Background: Remifentanil-induced postoperative hyperalgesia (RIH) refers to a state of hyperalgesia or aggravated pre-existing pain after remifentanil exposure. There has been considerable interest in understanding and preventing RIH. However, the mechanisms responsible for RIH are still not completely understood. Toll-like receptor 4 (TLR4), a classic innate immune receptor, has been detected in sensory neurons and participates in various nociceptive conditions, whereas its role in RIH remains unclear. Transient receptor potential ankyrin 1 (TRPA1) always serves as a nociceptive channel, whereas its role in RIH has not yet been investigated. This study aimed to determine whether the TLR4 signaling pathway in sensory neurons engaged in the development of RIH and the possible involvement of TRPA1 during this process. Methods: A rat model of remifentanil-induced postoperative hyperalgesia (RIH) was established, which presented decreased paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL). The mRNA and protein expression levels of TLR4, phosphorylated NF-κB, and TRPA1 in the dorsal root ganglion (DRG) from RIH model were analyzed by real-time PCR, western blot, and immunofluorescence. The TLR4 antagonist TAK-242 and the TRPA1 antagonist HC-030031 were applied to determine the role of sensory neuron TLR4 signaling and TRPA1 in RIH. Results: Compared with control, PWMT and PWTL were significantly decreased in RIH model. Moreover, the mRNA and protein expression of TLR4 and TRPA1 in DRG were upregulated after remifentanil exposure together with increased NF-κB phosphorylation. TLR4 antagonist TAK-242 mitigated mechanical pain in RIH together with downregulated expression of TLR4, phosphorylated NF-κB, and TRPA1 in DRG neurons. In addition, TRPA1 antagonist HC-030031 also alleviated mechanical pain and decreased TRPA1 expression in RIH without affecting TLR4 signaling in DRG. Conclusions: Taken together, these results suggested that activation of TLR4 signaling pathway engaged in the development of RIH by regulating TRPA1 in DRG neurons. Blocking TLR4 and TRPA1 might serve as a promising therapeutic strategy for RIH.

Chronic and Sustained High-Dose Opioid Use in an Integrated Health System

INTRODUCTION

The Centers for Disease Control and Prevention Guideline for Prescribing Opioids for Chronic Pain released in 2016 had led to decreases in opioid prescribing. This study sought to examine chronic and sustained high-dose prescription opioid use in an integrated health system.

METHODS

A serial cross-sectional study was conducted in 2021 to estimate the annual age-adjusted prevalence and incidence of chronic and high-dose opioid use among demographically diverse noncancer adults in an integrated health system in Southern California during 2013-2020. Interrupted time-series analysis with segmented regression was conducted to estimate changes in the trends in annual rates before (2013-2015) and after (2017-2020) the 2016 guideline, treating 2016 as a wash-out period.

RESULTS

Prevalence and incidence of chronic use and sustained high-dose use had started to decrease after a health system intervention program before the 2016 Centers for Disease Control and Prevention guideline release and continued to decline after the guideline. Among those with sustained high-dose use, there was a substantial decrease in persons with an average daily dosage ≥90 morphine milligram equivalent and concurrent benzodiazepine use. An accelerated decrease in prevalent chronic use after the guideline was observed (slope change: -11.1 [95% CI= -20.3, -1.9] users/10,000 person-years, p=0.03). The incidence of chronic use and sustained high-dose use continued to decrease after the guideline release but at a slower pace.

CONCLUSIONS

Implementing evidence-based prescribing guidelines was associated with a decrease in chronic and sustained high-dose prescription opioid use.

Postoperative Pain in Patients Undergoing Cancer Surgery and Intravenous Patient-Controlled Analgesia Use: The First and Second 24 h Experiences

INTRODUCTION

Postoperative cancer pain imposes severe physical and psychological problems. We aimed to investigate the pain experiences of patients with cancer after surgery, analyze the impact of infusion volume by patient-controlled analgesia (PCA), and explore the variations between day 1 and day 2.

METHODS

Data were retrospectively extracted from a large health data platform. Descriptive statistics were presented for the demographic and clinical profiles of patients. Multiple logistic regression analyses were performed to evaluate associations between intensity of pain and PCA use after adjustment for risk factors.

RESULTS

Among 11,383 patients with cancer, the incidence of pain (moderate to severe pain) was 93.3% (18.3%) at the first 24 h after operation, while the respect values decreased to 91.1% and 9.5% at the second 24 h. Further, female patients consistently experienced higher risk of pain over the whole 48 h postoperatively. Surgical sites were related to pain risk, with the highest risk among the respiratory system (OR 2.077, 95% CI 1.392-3.100). High doses of continuous volume (OR 2.453, 95% CI 1.742-3.456) and total volume (OR 2.830, 95% CI 2.037-3.934) of infusions were related to 1-3-fold elevated pain risk. Additionally, the observed associations were mostly repeated and could be up to over 10 times when pain was evaluated with number of PCA pump compressions instead of Numerical Rating Scale (NRS).

CONCLUSIONS

High risk of postoperative cancer pain, particularly among the high PCA dose group, could possibly indicate inadequate pain control, and presence of modifiable risk factors warrants more aggressive pain management strategies perioperatively.

Comparison of Single Target-Controlled Infusion Pump-Delivered Mixed Propofol and Remifentanil with Two Target-Controlled Infusion Pumps-Delivered Propofol and Remifentanil in Patients Undergoing Breast Cancer Surgery-A Prospective Study

Total intravenous anesthesia (TIVA) with remifentanil and propofol (RP) is considered to be an ideal type of general anesthesia (GA) for pediatric and adult patients undergoing medical procedures. However, delivery of an RP mixture by target-controlled infusion (TCI) for GA in surgical procedures has not been described. We investigated the merit of this approach for breast cancer surgery. Eighty-four patients (n = 42 per group) were randomly allocated to propofol and remifentanil either delivered by separate TCI pumps (S group) or in an RP mixture by a single TCI pump (M group). Dosages were adjusted based on the bispectral index (BIS) and the analgesia nociception index (ANI). The primary outcomes were adequate anesthesia (BIS 40-60 and ANI 50-70, respectively), acceptable hemodynamic fluctuations (<30% of baseline) with less frequent TCI pump adjustments, bolus injections of anesthetics, and total consumption of anesthetics during the procedure. The secondary endpoints included time of emergence from anesthesia, patient satisfaction, postoperative pain, rescue with opioids, and adverse events. The characteristics of patients, hemodynamic parameters, BIS and ANI scores, duration of surgery, anesthesia, and emergence were not significantly different between groups. The adjustment frequency of TCI was significantly higher in the S group (3 (range 0-6) vs. 2 (0-6) times; p = 0.005). The total dosage of anesthetics, pain rating, patient satisfaction, need for opioids postoperatively, and incidence of adverse events were not significantly different. We have demonstrated that this RP mixture provided adequate hypnotic and analgesic effects under BIS and ANI monitoring in patients undergoing breast cancer surgery within 1 h.

Spinal NLRP3 inflammasome activation mediates IL-1β release and contributes to remifentanil-induced postoperative hyperalgesia by regulating NMDA receptor NR1 subunit phosphorylation and GLT-1 expression in rats

BACKGROUND

Trafficking and activation of N-methyl-D-aspartate (NMDA) receptors play an important role in initiating and maintaining postoperative remifentanil-induced hyperalgesia (RIH). Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome has been linked to the development of inflammatory and neuropathic pain. We hypothesized that activation of NLRP3 inflammasome mediates IL-1β release and contributes to RIH in rats by increasing NMDA receptor NR1 (NR1) subunit phosphorylation and decreasing glutamate transporter-1 (GLT-1) expression.

METHODS

Acute exposure to remifentanil (1.2 μg/kg/min for 60 min) was used to establish RIH in rats. Thermal and mechanical hyperalgesia were tested at baseline (24 h before remifentanil infusion) and 2, 6, 24, and 48 h after remifentanil infusion. The levels of IL-1β, GLT-1, phosphorylated NR1 (phospho-NR1), and NLRP3 inflammasome activation indicators [NLRP3, Toll-like receptor 4 (TLR4), P2X purinoceptor 7 (P2X7R), and caspase-1] were measured after the last behavioral test. A selective IL-1β inhibitor (IL-1β inhibitor antagonist; IL-1ra) or three different selective NLRP3 inflammasome activation inhibitors [(+)-naloxone (a TLR4 inhibitor), A438079 (a P2X7R inhibitor), or ac-YVADcmk (a caspase-1 inhibitor)] were intrathecally administered immediately before remifentanil infusion into rats.

RESULTS

Remifentanil induced significant postoperative hyperalgesia, increased IL-1β and phospho-NR1 levels and activated the NLRP3 inflammasome by increasing TLR4, P2X7R, NLRP3, and caspase-1 expression, but it decreased GLT-1 expression in the L4-L6 spinal cord segments of rats, which was markedly improved by intrathecal administration of IL-1ra, (+)-naloxone, A438079, or ac-YVADcmk.

CONCLUSION

NLRP3 inflammasome activation mediates IL-1β release and contributes to RIH in rats by inducing NMDA receptor NR1 subunit phosphorylation and decreasing GLT-1 expression. Inhibiting the activation of the NLRP3 inflammasome may be an effective treatment for RIH.

A Review of Potential National Chronic Pain Surveillance Systems in the United States

Pain has been established as a major public health problem in the United States (U.S.) with 50 million adults experiencing chronic pain and 20 million afflicted with high-impact chronic pain (ie, chronic pain that interferes with life or work activities). High financial and social costs are associated with chronic pain. Over the past 2 decades, pain management has been complicated by the marked increase in opioids prescribed to treat chronic noncancer pain and by the concurrent opioid crisis. Monitoring the prevalence of chronic pain and pain management is especially important because pain management is changing in uncertain ways. We review potential U.S. chronic pain surveillance systems, present potential difficulties of chronic pain surveillance, and explore how to address chronic pain surveillance in the current opioid era. We consider case definitions, severity, anatomic site, and varieties of chronic pain management strategies in reviewing and evaluating national surveys for chronic pain surveillance. Based on the criteria evaluated, the National Health Interview Survey offers the best single source for pain surveillance as the pain-related questions administered are brief, valid, and cover a broad scope of pain-related phenomena. PERSPECTIVE: This review article describes data sources that can be leveraged to conduct national chronic pain surveillance in the United States, explores case defining or pain-related questions administered, and evaluates them against 8 surveillance attributes.

Opioid Utilization and Management in the Setting of Stewardship During Inpatient Rehab Care

Background

Opioid utilization and management in an inpatient rehabilitation setting have not been widely described, despite the unique opportunities that exist in this setting to support opioid stewardship across transitions in care. We aimed to characterize opioid utilization and management by interprofessional teams across a large, inpatient rehabilitation setting after incorporation of opioid stewardship principles by pharmacists as part of their daily practice.

Patients and methods

This was a retrospective chart review at Toronto Rehab, University Health Network, Toronto, Canada. Patients with admission orders for any opioid from November 2017 to February 2018 were included. Complex continuing care and palliative care patients were excluded. Descriptive statistics were primarily used to describe the data as well as univariate linear regression to compare associations with milligram morphine equivalent (MME) reduction.

Results

A total of 448 patients were included. A reduction in total daily MME was seen in 49% (n=219) of the patients during their inpatient stay, with 73% (n=159) of these patients having a reduction of ≥50%. Sixty-nine percent (n=311) of the patients received an opioid prescription at discharge, with most scheduled (90%, n=98) with a supply of less than 30 days. Rehabilitation length of stay was correlated with a MME decrease during rehab (p<0.01), suggesting that longer lengths of stay contributed to a greater reduction in MME. Patients with chronic opioid use prior to acute care admission (p=0.01), and those who started extended-release opioids during acute care (p=0.02) were significantly less likely to discontinue opioids during rehab stay.

Conclusion

Opioid utilization and management in the setting of opioid stewardship across inpatient rehab and transitions of care were characterized. Opportunities exist for further quality improvement initiatives within inpatient rehabilitation and acute care settings to identify and support patients with complex pain management needs.

Pain, Anxiety, and the Continuous Use of Opioids and Benzodiazepines in Trauma Intensive Care Unit Survivors: An Exploratory Study

OBJECTIVE

To evaluate at-home opioid and benzodiazepine use, the degrees of pain and anxiety, and the incidence of probable withdrawal in post-discharge Trauma Intensive Care Unit (TICU) survivors.

METHODS

This was an exploratory study of post-TICU survivors who had participated in a previous study of opioid and benzodiazepine withdrawal. We surveyed survivors by telephone asking for retrospective information (during their first 4-months postdischarge- Time 1) and current information (around 2-years post-discharge- Time 2).

RESULTS

A mostly male (82%), young (median 38 years [IQR, 28-52]) sample of 27 TICU survivors reported using opioids (56%) at Time 1 for a median of 30 (IQR,14-90) days. Twelve percent of 26 survivors were still using opioids at Time 2. Sixty percent of the survivors had pain during Time 1, a median pain score of 6 (IQR, 5-8) on a 0-10 numeric rating scale (NRS).; 57% had pain at Time 2, median NRS score=6 (IQR, 4-7). Sixty-five percent of survivors had anxiety during Time 1, NRS median=7 (IQR, 5-9); 50% had anxiety at Time 2, NRS median= 6 (IQR, 3-7). At Time 1, 26% used prescribed benzodiazepines, and 12% used benzodiazepines at Time 2. Five and one of the 27 patients reported symptoms of opioid or benzodiazepine withdrawal, respectively, upon discontinuation or weaning.

CONCLUSION

Many TICU survivors had discontinued opioid/benzodiazepine prescriptions by 4-months post discharge while half reporting pain/anxiety for up to 2-years. Investigating the effects of acute-to-chronic pain in ICU survivors and gaining a better understanding of the mechanisms of prolonged opioid use are warranted.

Worst pain intensity and opioid intake during the early postoperative period were not associated with moderate-severe pain 12 months after total knee arthroplasty - a longitudinal study

OBJECTIVES

There are several known predictors of pain after total knee arthroplasty (TKA). However, it is unclear whether acute postoperative pain intensity and postoperative opioid intake are associated with pain 12 months after TKA. Thus, the aim of this study was to assess whether worst pain intensity and opioid intake during the early postoperative period are associated with moderate-severe pain 12 months after TKA.

METHODS

A total of 202 patients undergoing primary TKA between October 2012 and September 2014 were prospectively enrolled. Age, sex, contralateral knee pain, BMI, physical status and opioid intake were collected preoperatively. Ketamine and daily opioid intake were collected on postoperative days (POD) 0-3. Using the Brief Pain Inventory, patients' "worst pain intensity" was measured preoperatively, on POD 0-4, and 12 months after TKA. Two logistic regression models evaluated the independent association of early postoperative pain intensity (model 1) and postoperative opioid intake (model 2) with moderate-severe pain 12 months after TKA, adjusting for possible confounders.

RESULTS

In total, 187 patients with data at the 12 month postoperative follow-up were included in this analysis. Pain intensity on POD2 and POD3, as well as preoperative pain and BMI, were significantly associated with pain at 12 months in univariate models. However, in multivariable models adjusted for preoperative pain and BMI, neither pain intensity on POD 0-4 (model 1) nor opioid intake on POD 0-3 (model 2) were associated with pain at 12 months. Preoperative pain was still significant in both models, but BMI remained significant only in model 2.

CONCLUSIONS

Worst pain intensity and opioid intake during the early postoperative period were not associated with moderate-severe pain 12 months after TKA when controlling for potential confounders. More research is needed to confirm these findings.

Delta opioid receptors in Nav1.8 expressing peripheral neurons partially regulate the effect of delta agonist in models of migraine and opioid-induced hyperalgesia

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DOR in Nav1.8 cells do not regulate anti-migraine effects of DOR agonist.

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DOR in Nav1.8 cells is critical for effect of DOR agonist in peripheral OIH.

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DOR in Nav1.8 cells is not necessary for effect of DOR agonist in cephalic OIH.

Migraine is one of the most common pain disorders and causes disability in millions of people every year. Delta opioid receptors (DOR) have been identified as a novel therapeutic target for migraine and other headache disorders. DORs are present in both peripheral and central regions and it is unclear which receptor populations regulate migraine-associated effects. The aim of this study was to determine if DOR expressed in peripheral nociceptors regulates headache associated endpoints and the effect of delta agonists within these mouse models. We used a conditional knockout, in which DOR was selectively deleted from Nav1.8 expressing cells. Nav1.8-DOR mice and loxP control littermates were tested in models of chronic migraine-associated allodynia, opioid-induced hyperalgesia, migraine-associated negative affect, and aura. Nav1.8-DOR and loxP mice had comparable effect sizes in all of these models. The anti-allodynic effect of the DOR agonist, SNC80, was slightly diminished in the nitroglycerin model of migraine. Intriguingly, in the OIH model the peripheral effects of SNC80 were completely lost in Nav1.8-DOR mice while the cephalic effects remained intact. Regardless of genotype, SNC80 continued to inhibit conditioned place aversion associated with nitroglycerin and decreased cortical spreading depression events associated with migraine aura. These results suggest that DOR in Nav1.8-expressing nociceptors do not critically regulate the anti-migraine effects of delta agonist; and that brain-penetrant delta agonists would be a more effective drug development strategy.

The Influence of Opioids on Transcutaneous Electrical Nerve Stimulation Effects in Women With Fibromyalgia

Transcutaneous electrical nerve stimulation (TENS) uses endogenous opioids to produce analgesia, and effectiveness can be reduced in opioid-tolerant individuals'. We examined TENS effectiveness (primary aim), and differences in fibromyalgia symptoms (secondary aim), in women with fibromyalgia regularly taking opioid (RTO) medications compared with women not- regularly taking opioids (not-RTO). Women (RTO n = 79; not-RTO not-n = 222) with fibromyalgia with daily pain levels ≥4 were enrolled and categorized into RTO (taking opioids at least 5 of 7 days in last 30 days) or not-RTO groups. Participants were categorized into tramadol n = 52 (65.8%) and other opioids n = 27 (34.2%) for the RTO group. Participants were phenotyped across multiple domains including demographics, fibromyalgia characteristics pain, fatigue, sleep, psychosocial factors, and activity. Participants were randomized to active TENS (n = 101), placebo TENS (n = 99), or no TENS (n = 99) for 1-month with randomization stratified by opioid use. Active TENS was equally effective in movement-evoked pain in those in the RTO and not-RTO groups. Women with fibromyalgia in the RTO group were older (P = .002), lower-income (P = .035), more likely to smoke (P = .014), and more likely to report depression (P = .013), hypertension (P = .005) or osteoarthritis (P = .027). The RTO group demonstrated greater bodily pain on SF-36 (P = .005), lower quality of life on the physical health component of the SF-36 (P = .040), and greater fatigue (MAF-ADL P = .047; fatigue with sit to stand test (P = .047) These differences were small of and unclear clinical significance. In summary, regular use of opioid analgesics does not interfere with the effectiveness of TENS for movement-evoked pain. Clinical Trial Registration Number: NCT01888640. PERSPECTIVE: Individuals treated with mixed frequency TENS at a strong but comfortable intensity that was taking prescription opioid analgesics showed a significant reduction in movement-evoked pain and fatigue. These data support the use of TENS, using appropriate parameters of stimulation, as an intervention for individuals with fibromyalgia taking opioid analgesics.

How do people who use drugs receiving Opioid Medication Therapy perceive their treatment ? A multicentre study

Background

The resurgence of heroin use and the misuse of pharmaceutical opioids are some of the reasons for a worldwide increase in opioid dependence. Opioid Medication Therapies (OMT) have amply demonstrated their efficacy. From a medical point of view, the main objectives of OMT concern medical and social outcomes, centred on risk reduction and the cessation of opioid use. But patient points of view can differ and few studies have explored opioid-dependent patient viewpoints on their OMT. This variable seems important to consider in a patient-centred approach. The aim of our study was to explore points of view of people who use drugs (PWUD) treated with OMT, in a large multicentre sample.

Method

A cross-sectional multicentre study explored the points of view of PWUD with Opioid Use Disorder following OMT. Data regarding the patients’ points of view were collected using a self-administered questionnaire developed by the scientific committee of the study. A descriptive analysis and an exploratory factor analysis were performed to explore the structure of items exploring patient viewpoints.

Results

263 opioid dependent PWUD were included, a majority were men consuming heroin prior to being prescribed OMT. 68% were on methadone, 32% were on buprenorphine. Most PWUD identified a positive impact on their lives, with 92.8% agreeing or strongly agreeing that OMT had changed a lot of things in their lives. The exploratory factor analysis identified three factors: (F1) items related to points of views concerning the objectives and efficacy of OMT; (F2) items related to the legitimacy of OMT as a treatment compared to a drug, (F3) items related to experiences and relationships with OMT.

Conclusion

Patient viewpoints on efficacy were correlated with the pharmacological benefits of OMT and with the associated psychosocial measures. The implications of OMT in relationships, such as the feeling of being judged, concerned a majority. Points of view were ambivalent concerning the role of OMT as a treatment or as a drug. Involving patient points of view in therapeutic strategies decisions could help enhance positive views among PWUD on OMT and help PWUD towards their recovery.

Trial registration: OPAL study was registered: (NCT01847729).

Opioid Therapy in Cancer Patients and Survivors at Risk of Addiction, Misuse or Complex Dependency

A clinical conundrum can occur when a patient with active opioid use disorder (OUD) or at elevated risk for the condition presents with cancer and related painful symptoms. Despite earlier beliefs that cancer patients were relatively unaffected by opioid misuse, it appears that cancer patients have similar risks as the general population for OUD but are more likely to need and take opioids. Treating such patients requires an individualized approach, informed consent, and a shared decision-making model. Tools exist to help stratify patients for risk of OUD. While improved clinician education in pain control is needed, patients too need to be better informed about the risks and benefits of opioids. Patients may fear pain more than OUD, but opioids are not always the most effective pain reliever for a given patient and some patients do not tolerate or want to take opioids. The association of OUD with mental health disorders (dual diagnosis) can also complicate delivery of care as patients with mental health issues may be less adherent to treatment and may use opioids for “chemical coping” as much as for pain control.

Review of publications evaluating opioid use in patients with inflammatory rheumatic disease

PURPOSE OF REVIEW

This article discusses publications assessing the prevalence, efficacy, and safety of opioid analgesics in patients with rheumatic diseases, including rheumatoid arthritis, systemic lupus erythematosus, psoriatic arthritis, ankylosing spondylitis, and systemic sclerosis.

RECENT FINDINGS

Recent studies show long-term opioid use is common in patients with inflammatory rheumatic disease. We did not find any studies demonstrating improved function or pain control with long-term opioid use in people with rheumatic diseases. Some data shows potential adverse effects including increased risk for fractures and opioid poisoning hospitalizations. There is evidence demonstrating an association of opioid use with mental health disorders, fibromyalgia, obesity, and disability, although causative links have not been established. Only minimal reductions in opioid use were observed after initiation of biologic disease modifying antirheumatic drugs (DMARDs). Studies have shown delayed DMARD initiation and reduced DMARD use in patients on opioids, raising concerns that these analgesics may delay care or initially mask symptoms of active disease.

SUMMARY

Available literature highlights high levels of opioid use in people with rheumatic disease, without scientific evidence to support efficacy for chronic pain control and increasing evidence of adverse events. These findings strongly suggest that opioids do not have a routine role in the chronic management of inflammatory rheumatic diseases.

Painful Truth: The Need to Re-Center Chronic Pain on the Functional Role of Pain

Pain is undesirable, whether it is a symptom of mild or severe illness or instead indicates disorder in the nervous system’s ability to perceive and process sensory information. Nonetheless, pain is part of the body’s ability to defend itself and promote its own survival—this is its fundamental evolutionary function. This normal expression of pain is not limited to what is considered useful because it alerts us to the initiation of illness. It also applies to pain that continues when illness or noxious stimuli persist. However, the parameters of what is here termed functional pain are not fully understood and are seldom explicitly the focus of research. This paper posits that failure to appreciate the functional role of pain in research has had significant unintended consequences and may be contributing to inconsistent research findings. To that end, the paper describes the misclassification issue at the core of chronic pain research—whether a given pain reflects functional or pathological processes—and discusses research areas where reconsidering the functional role of pain may lead to advancements.

Opioids for chronic pain management in patients with dialysis-dependent kidney failure

Chronic pain is highly prevalent among adults treated with maintenance haemodialysis (HD) and has profound negative effects. Over four decades, research has demonstrated that 50-80% of adult patients treated with HD report having pain. Half of patients with HD-dependent kidney failure (HDKF) have chronic moderate-to-severe pain, which is similar to the burden of pain in patients with cancer. However, pain management in patients with HDKF is often ineffective as most patients report that their pain is inadequately treated. Opioid analgesics are prescribed more frequently for patients receiving HD than for individuals in the general population with chronic pain, and are associated with increased morbidity, mortality and health-care resource use. Furthermore, current opioid prescribing patterns are frequently inconsistent with guideline-recommended care. Evidence for the effectiveness of opioids in pain management in general, and in patients with HDKF specifically, is lacking. Nonetheless, long-term opioid therapy has a role in the treatment of some patients when used selectively, carefully and combined with an ongoing assessment of risks and benefits. Here, we provide a comprehensive overview of the use of opioid therapy in patients with HDKF and chronic pain, including a discussion of buprenorphine, which has potential as an analgesic option for patients receiving HD owing to its unique pharmacological properties.

Inhibition of Oligodendrocyte Apoptosis in the Prelimbic Medial Prefrontal Cortex Prevents Fentanyl-induced Hyperalgesia in Rats

Opioid-induced hyperalgesia (OIH) is a problem associated with prolonged use of opioids in chronic pain management, and its effective treatment has been hampered by lack of mechanistic evidence. Oligodendrocytes have recently been linked with several pain-related diseases; however, little is known its role in OIH. The prelimbic medial prefrontal cortex (PL-mPFC) has emerged as a significant center of pain regulation, and is rich in oligodendrocytes. Herein we explored the effect of oligodendrocyte apoptosis of PL-mPFC on OIH. Using a fentanyl-induced rat model of OIH and proteomics analysis of the PL-mPFC, we observed a downregulation in 5 types of myelin-related proteins originating from oligodendrocytes; this was further verified by western blotting. Meanwhile, cleaved-caspase 3 (an apoptosis marker) was increased, whereas the oligodendrocyte precursor cell (OPC) marker NG2 remained unchanged. These results suggest that downregulated myelin-related proteins may be associated with oligodendrocyte apoptosis rather than a reduction in their generating source, and immunohistochemistry confirmed this hypothesis. Behaviorally, prophylactic blockade of oligodendrocyte apoptosis by microinjection of z-DEVD-fmk into the PL-mPFC prevented fentanyl-induced mechanical and thermal hyperalgesia, but downregulated myelin basic protein (mbp) gradually recovered in 12 h. We suggest that OIH may be primed in part via oligodendrocyte apoptosis in the PL-mPFC. PERSPECTIVE: In this study we showed that oligodendrocyte apoptosis in the PL-mPFC is a key trigger for fentanyl-induced hyperalgesia. Targeting oligodendrocyte apoptosis in the PL-mPFC may prevented hyperalgesia priming induced by fentanyl.

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.

Development and Validation of Pediatric Opioid Analgesia Self-Instruction System (PedOASIS): An Opioid Knowledge Tool for Pediatric Clinicians

BACKGROUND

Acute pain is common in children and young adults with cancer and sickle cell disease. Current training curricula fail to adequately impart skills for pain management. We sought to develop and validate an education and assessment tool to address the safe effective use of opioids for pain management by pediatrics trainees.

METHODS

The first version of the tool contained 10 case-based, multiple-choice questions. It was pilot tested within a medium-sized pediatric residency program using preintervention and postintervention surveys to assess residents' knowledge and comfort related to prescribing opioids. Content validation was performed through an expert panel of physicians. Internal reliability was tested by administering the tool to learners and practitioners with varying levels of training.

RESULTS

Comfort with choosing and converting between opioids increased significantly in pilot testing (P=0.005). Mean objective knowledge scores increased from 51% to 85.9% (P<0.001). The revised tool showed internal reliability within each group (Cronbach alpha 0.71 to 0.78) and significant differences in mean scores between groups (F ratio=9.45, P=0.0002).

CONCLUSIONS

This tool demonstrates validity and internal reliability. Its use was associated with short-term educational gains and it garnered overall favorable feedback from users. Further testing is needed to assess the duration of these gains.

Pain Control and Opioid Use in ICU should be a Quality Parameter

How to cite this article: Garg SK, Garg P. Pain Control and Opioid Use in ICU should be a Quality Parameter. Indian J Crit Care Med 2021; 25(10):1205–1206.

The Role of Melanocortin Plasticity in Pain-Related Outcomes After Alcohol Exposure

The global COVID-19 pandemic has shone a light on the rates and dangers of alcohol misuse in adults and adolescents in the US and globally. Alcohol exposure during adolescence causes persistent molecular, cellular, and behavioral changes that increase the risk of alcohol use disorder (AUD) into adulthood. It is established that alcohol abuse in adulthood increases the likelihood of pain hypersensitivity and the genesis of chronic pain, and humans report drinking alcohol to relieve pain symptoms. However, the longitudinal effects of alcohol exposure on pain and the underlying CNS signaling that mediates it are understudied. Specific brain regions mediate pain effects, alcohol effects, and pain-alcohol interactions, and neural signaling in those brain regions is modulated by neuropeptides. The CNS melanocortin system is sensitive to alcohol and modulates pain sensitivity, but this system is understudied in the context of pain-alcohol interactions. In this review, we focus on the role of melanocortin signaling in brain regions sensitive to alcohol and pain, in particular the amygdala. We also discuss interactions of melanocortins with other peptide systems, including the opioid system, as potential mediators of pain-alcohol interactions. Therapeutic strategies that target the melanocortin system may mitigate the negative consequences of alcohol misuse during adolescence and/or adulthood, including effects on pain-related outcomes.

Postoperative Opioid Prescribing After Female Pelvic Medicine and Reconstructive Surgery

OBJECTIVE

This study aimed to provide female pelvic medicine and reconstructive surgery (FPMRS) providers with evidence-based guidance on opioid prescribing following surgery.

METHODS

A literature search of English language publications between January 1, 2000, and March 31, 2021, was conducted. Search terms identified reports on opioid prescribing, perioperative opioid use, and postoperative pain after FPMRS procedures. Publications were screened, those meeting inclusion criteria were reviewed, and data were abstracted. Data regarding the primary objective included the oral morphine milligram equivalents of opioid prescribed and used after discharge. Information meeting criteria for the secondary objectives was collected, and qualitative data synthesis was performed to generate evidence-based practice guidelines for prescription of opioids after FPMRS procedures.

RESULTS

A total of 6,028 unique abstracts were identified, 452 were screened, and 198 full-text articles were assessed for eligibility. Fifteen articles informed the primary outcome, and 32 informed secondary outcomes.

CONCLUSIONS

For opioid-naive patients undergoing pelvic reconstructive surgery, we strongly recommend surgeons to provide no more than 15 tablets of opioids (roughly 112.5 morphine milligram equivalents) on hospital discharge. In cases where patients use no or little opioids in the hospital, patients may be safely discharged without postoperative opioids. Second, patient and surgical factors that may have an impact on opioid use should be assessed before surgery. Third, enhanced recovery pathways should be used to improve perioperative care, optimize pain control, and minimize opioid use. Fourth, systemic issues that lead to opioid overprescribing should be addressed. Female pelvic medicine and reconstructive surgery surgeons must aim to balance adequate postoperative pain control with individual and societal risks associated with excess opioid prescribing.

Evaluation of Chronic, Noncancer Pain Management Initiative in a Multidisciplinary Pain Clinic

BACKGROUND

Chronic pain management is a major challenge for primary care providers (PCPs). PCPs manage many patients with chronic pain and other comorbidities including mental health problems like post-traumatic stress disorder (PTSD) and depression. Chronic pain and opioid problems are a national crisis, particularly among veterans (U.S. Department of Veterans Affairs, 2019). There are many veterans with chronic non-cancer pain who are being treated with opioids. Chronic opioid use has contributed to an epidemic of opioid-related adverse events (VA, 2017). Opioids not only result in poor pain control, but have associated risks such as misuse, overdose, and diversion which may be fatal (Frieden & Houry, 2016).

AIMS

The aim of this project was to evaluate chronic non-cancer pain management of veterans using an advanced practice registered nurse (APRN)-led multidisciplinary team approach to incorporate non-opioid and non-pharmacologic modalities to affect self-reported pain and use of prescribed opioids.

METHODS

A retrospective quality improvement (QI) project was conducted in the multidisciplinary pain (MDP) clinic. The APRN used a biopsychosocial approach for chronic pain management guided by the Plan, Do, Study, Act (PDSA) cycle framework. Thirty-four patients who were utilizing opioids for pain management were included using convenience sampling from the MDP clinic. The APRN educated and treated patients with non-opioid medications and non-pharmacolog therapies. A 10-point pain scale and morphine equivalent daily dose (MEDD) were utilized pre- and post-intervention to evaluate the MDP clinic.

RESULTS

Participants were predominantly male (91.8%), with a mean age of 63.18 ± 15.39 years, and 36.4% of whom were retired. Only 20.6% of the participants reported the use of opioids for <12 months. Low back pain (93%) was the most common pain location. The mean baseline MEDD was 41.04 and the post tapered MEDD was 23.05; this revealed a significant decline in MEDD (p < .0001). A decline was also found between pre- and post-pain scores (ranges 0-8). There was a significant reported decline in pain scores with a baseline of 6.11 to post tapering pain of 3.1 (t = 4.99, df = 28, p < .0001). Participants preferred non-opioid medications 94% and non-pharmacologic therapy 86%, like physical therapy, yoga, and acupuncture. Fifty-one percent of patients were referred for injections and 46% were referred to primary care behavior health, which includes pain school, sleep hygiene classes, and cognitive behavior therapy.

CONCLUSIONS

APRNs are in a key position to assess and treat patients based on current evidence while facilitating opioid titration. This initiative highlights that safe tapering of opioids is possible when utilizing a multidisciplinary approach for chronic pain management. Findings support the use of non-pharmacologic and non-opioid therapy for chronic pain management which can result in reduced patient-reported pain. Further research is warranted to examine both pharmacologic (non-opioid) and non-pharmacologic strategies that promote pain management while tapering opioids.

Pediatric Palliative Care Pharmacy Pearls—A Focus on Pain and Sedation

Determining the optimal dosing regimen for pediatric patients is a challenge due to the lack of dosing guidelines and studies. In addition, many developmental pharmacology changes that occur throughout childhood that have profound impacts on the absorption, distribution, metabolism, and elimination of medications are commonly used in palliative care. Adding to that complexity, certain medications have different effects in the pediatric patient compared to the adult patient. Being aware of the pharmacokinetic changes, impact on neurodevelopment and unique medication factors that are present in pediatric patients helps clinicians treat the pediatric palliative care patient in the best and safest way possible.

Perspectives of patients with depression and chronic pain about bone health after a fragility fracture: A qualitative study

Background

Compromised bone health is often associated with depression and chronic pain.

Objective

To examine: (1) the experience of existing depression and chronic nonfracture pain in patients with a fragility fracture; and (2) the effects of the fracture on depression and pain.

Design

A phenomenological study guided by Giorgi's analytical procedures.

Setting and Participants

Fracture patients who reported taking prescription medication for one or more comorbidities, excluding compromised bone health.

Main Variables Studied

Patients were interviewed within 6 weeks of their fracture, and 1 year later. Interview questions addressed the recent fracture and patients' experience with bone health and their other health conditions, such as depression and chronic pain, including the medications taken for these conditions.

Results

Twenty‐six patients (5 men, 21 women) aged 45–84 years old with hip (n = 5) and nonhip (n = 21) fractures were recruited. Twenty‐one participants reported depression and/or chronic nonfracture pain, of which seven reported having both depression and chronic pain. Two themes were consistent, based on our analysis: (1) depression and chronic pain overshadowed attention to bone health; and (2) the fracture exacerbated reported experiences of existing depression and chronic pain.

Conclusion

Experiences with depression and pain take priority over bone health and may worsen as a result of the fracture. Health care providers treating fragility fractures might ask patients about depression and pain and take appropriate steps to address patients' more general emotional and physical state.

Patient Contribution

A patient representative was involved in the study conception, data interpretation and manuscript writing.