Reduced cold pain tolerance in chronic pain patients following opioid detoxification

Effectiveness of pain medication tapering in chronic pain patients: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to inventory all outcome measures that are affected by tapering in chronic noncancer pain and to investigate the effectiveness of tapering.

METHODS

A literature search was conducted from inception to April 2024 in MEDLINE via PubMed, Web of Science, SCOPUS, EMBASE, and PsycINFO.

RESULTS

The initial database search identified 3969 articles, which were screened by two independent reviewers. Studies evaluating pain medication tapering in adults with chronic noncancer pain were eligible for inclusion. In total, 57 and 34 articles were included in the systematic review and meta-analysis, respectively. Risk of bias assessment demonstrated poor, fair, and good quality in 30, 24, and three studies, respectively. Pain intensity was the most reported outcome measure, as reported in 28 studies. Furthermore, a random-effect three-level meta-analysis was performed. An overall effect size of 0.917 (95% confidence interval 0.61-1.22; P<0.001) was found, indicating a beneficial effect of tapering. In addition, a statistically significant improvement was demonstrated after tapering for pain intensity, headache disability, the number of headache days per month, anxiety, depression, the number of pills consumed per month, the number of days with medication intake per month, pain catastrophising, and pain interference. No statistically significant effect was observed for physical functioning, mental health-related quality of life, opioid use, pain self-efficacy, and physical health-related quality of life.

CONCLUSIONS

This systematic review revealed a broad range of outcome measures affected by tapering. Owing to the high risk of bias of the included articles, the results of this meta-analysis must be interpreted with caution.

SYSTEMATIC REVIEW PROTOCOL

CRD42023416343 (PROSPERO).

Intimate partner violence, substance use, and health comorbidities among women: A narrative review

Exposure to intimate partner violence (IPV), including physical, sexual, and psychological violence, aggression, and/or stalking, impacts overall health and can have lasting mental and physical health consequences. Substance misuse is common among individuals exposed to IPV, and IPV-exposed women (IPV-EW) are at-risk for transitioning from substance misuse to substance use disorder (SUD) and demonstrate greater SUD symptom severity; this too can have lasting mental and physical health consequences. Moreover, brain injury is highly prevalent in IPV-EW and is also associated with risk of substance misuse and SUD. Substance misuse, mental health diagnoses, and brain injury, which are highly comorbid, can increase risk of revictimization. Determining the interaction between these factors on the health outcomes and quality of life of IPV-EW remains a critical need. This narrative review uses a multidisciplinary perspective to foster further discussion and research in this area by examining how substance use patterns can cloud identification of and treatment for brain injury and IPV. We draw on past research and the knowledge of our multidisciplinary team of researchers to provide recommendations to facilitate access to resources and treatment strategies and highlight intervention strategies capable of addressing the varied and complex needs of IPV-EW.

Repeated Morphine Administration Increases TRPV1 mRNA Expression and Autoradiographic Binding at Supraspinal Sites in the Pain Pathway

Repeated morphine administration induces tolerance to its analgesic effects. A previous study reported that repeated morphine treatment activates transient receptor potential vanilloid type 1 (TRPV1) expression in the sciatic nerve, dorsal root ganglion, and spinal cord, contributing to morphine tolerance. In the present study, we analyzed TRPV1 expression and binding sites in supraspinal pain pathways in morphine-tolerant mice. The TRPV1 mRNA levels and binding sites were remarkably increased in the cortex and thalamus of these animals. Our data provide additional insights into the effects of morphine on TRPV1 in the brain and suggest that changes in the expression of, and binding to TRPV1 in the brain are involved in morphine tolerance.

Efficacy of interventions to reduce long term opioid treatment for chronic non-cancer pain: systematic review and meta-analysis

OBJECTIVE

To review interventions to reduce long term opioid treatment in people with chronic non-cancer pain, considering efficacy on dose reduction and discontinuation, pain, function, quality of life, withdrawal symptoms, substance use, and adverse events.

DESIGN

Systematic review and meta-analysis of randomised controlled trials and non-randomised studies of interventions.

DATA SOURCES

Medline, Embase, PsycINFO, CINAHL, and the Cochrane Library searched from inception to July 2021. Reference lists and previous reviews were also searched and experts were contacted.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Original research in English. Case reports and cross sectional studies were excluded.

DATA EXTRACTION AND SYNTHESIS

Two authors independently selected studies, extracted data, and used the Cochrane risk-of-bias tools for randomised and non-randomised studies (RoB 2 and ROBINS-I). Authors grouped interventions into five categories (pain self-management, complementary and alternative medicine, pharmacological and biomedical devices and interventions, opioid replacement treatment, and deprescription methods), estimated pooled effects using random effects meta-analytical models, and appraised the certainty of evidence using GRADE (grading of recommendations, assessment, development, and evaluation).

RESULTS

Of 166 studies meeting inclusion criteria, 130 (78%) were considered at critical risk of bias and were excluded from the evidence synthesis. Of the 36 included studies, few had comparable treatment arms and sample sizes were generally small. Consequently, the certainty of the evidence was low or very low for more than 90% (41/44) of GRADE outcomes, including for all non-opioid patient outcomes. Despite these limitations, evidence of moderate certainty indicated that interventions to support prescribers' adherence to guidelines increased the likelihood of patients discontinuing opioid treatment (adjusted odds ratio 1.5, 95% confidence interval 1.0 to 2.1), and that these prescriber interventions as well as pain self-management programmes reduced opioid dose more than controls (intervention v control, mean difference -6.8 mg (standard error 1.6) daily oral morphine equivalent, P<0.001; pain programme v control, -14.31 mg daily oral morphine equivalent, 95% confidence interval -21.57 to -7.05).

CONCLUSIONS

Evidence on the reduction of long term opioid treatment for chronic pain continues to be constrained by poor study methodology. Of particular concern is the lack of evidence relating to possible harms. Agreed standards for designing and reporting studies on the reduction of opioid treatment are urgently needed.

REVIEW REGISTRATION

PROSPERO CRD42020140943.

Benefits and Harms of Long-term Opioid Dose Reduction or Discontinuation in Patients with Chronic Pain: a Rapid Review

BACKGROUND

Many clinicians are reevaluating the use of long-term opioid therapy (LTOT) for chronic pain in response to the opioid crisis and calls from organizations including the Centers for Disease Control & Prevention to limit prescribing of high-dose opioids. However, this practice change is occurring largely in the absence of data regarding patient outcomes. A 2017 systematic review found inconclusive evidence on the impact of LTOT dose reduction and discontinuation on pain severity and function, quality of life, withdrawal symptoms, substance abuse, and adverse effects. This rapid systematic review provides an updated evidence synthesis of patient outcomes following LTOT dose reduction including serious harms such as overdose and suicide.

METHODS

We systematically searched numerous bibliographic databases from January 2017 (the end search date of the 2017 systematic review) through May 2020. One reviewer used prespecified criteria to assess articles for inclusion, evaluate study quality, abstract data, and grade strength of evidence, with a second reviewer checking.

RESULTS

We included 49 studies-1 systematic review, 34 studies included in that systematic review, and 14 new studies. We prioritized evidence synthesis of 19 studies with the most applicability to the Veteran population and outpatient settings. Among these studies, improvements in mean pain scores were common among patients tapering opioids while participating in intensive multimodal pain interventions and mostly unchanged with less intensive or nonspecific co-interventions. Our confidence in these findings is low due to methodological limitations of the studies. Observational data suggests that serious harms such as opioid overdose and suicidal ideation can occur following opioid dose reduction or discontinuation, but the incidence of these harms at the population level is unknown.

DISCUSSION

The net balance of benefits and harms of LTOT dose reduction for patients with chronic pain is unclear. Clinicians should closely monitor patients during the tapering process given the potential for harm.

Multidisciplinary care for opioid dose reduction in patients with chronic non-cancer pain: A systematic realist review

CONTEXT

Opioid related deaths are at epidemic levels in many developed nations globally. Concerns about the contribution of prescribed opioids, and particularly high-dose opioids, continue to mount as do initiatives to reduce prescribing. Evidence around opioid tapering, which can be challenging and potentially hazardous, is not well developed. A recent national guideline has recognized this and recommended referral to multidisciplinary care for challenging cases of opioid tapering. However, multidisciplinary care for opioid tapering is not well understood or defined.

OBJECTIVE

Identify the existing literature on any multidisciplinary care programs that evaluate impact on opioid use, synthesize how these programs work and clarify whom they benefit.

STUDY DESIGN

Systematic rapid realist review.

DATASET

Bibliographic databases (MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Library), grey literature, reference hand search and formal expert consultation.

RESULTS

95 studies were identified. 75% of the programs were from the United States and the majority (n = 62) were published after 2000. A minority (n = 23) of programs reported on >12 month opioid use outcomes. There were three necessary but insufficient mechanisms common to all programs: pain relief, behavior change and active medication management. Programs that did not include a combination of all three mechanisms did not result in opioid dose reductions. A concerning 20-40% of subjects resumed opioid use within one year of program completion.

CONCLUSIONS

Providing alternative analgesia is insufficient for reducing opioid doses. Even high quality primary care multidisciplinary care programs do not reduce prescribed opioid use unless there is active medication management accomplished by changing the primary opioid prescriber. Rates of return to use of opioids from these programs are very concerning in the current context of a highly potent and lethal street drug supply. This contextual factor may be powerful enough to undermine the modest benefits of opioid dose reduction via multidisciplinary care.

Psycho-physiological response to pain among individuals with comorbid pain and opioid use disorder: Implications for patients with prolonged abstinence

Background: Individuals with comorbid opioid addiction and pain (COAP) relapse 3-5 times more often than patients with opioid use disorder (OUD) but without pain. However, psychophysiological responses to pain among a COAP population are unknown. Objectives: We hypothesized that those on Medications for Opioid Use Disorder (MOUD) with chronic pain, relative to opioid-naïve chronic pain individuals, would show greater psycho-physiological pain reactivity and slower recovery when exposed to acute pain. Methods: Four groups with chronic pain were recruited (N = 120; 60% Female): 1) MOUD-methadone; 2) MOUD-buprenorphine; 3) history of completed MOUD with prolonged opioid abstinence (PA; M_abstinence = 121 weeks; SD = 23.3); and 4) opioid-naïve. We assessed heart rate (HR), galvanic skin conductance (GSC), peripheral temperature, and frontalis electromyography (EMG) during a cold pain task. Results: MOUD subjects had delayed HR reactivity to pain compared to those not on MOUD (PA & opioid-naïve; F(3,119) = 2.87, p < .04). The PA group showed a normal HR reactivity pattern, but had higher HR compared to the opioid-naïve group. The GSC group x time analysis showed the PA group had greater baseline levels and pain reactivity than the other groups (F(3,119) = 3.84, p < .02). The opioid-naïve group had lower reactivity on peripheral temperature compared to other groups (F(3,119) = 9.69, p < .001). Conclusion: Greater psychophysiological reactivity to pain was experienced by co-morbid OUD/chronic pain subjects who had been opioid abstinent for an extended period, possibly due to the lack of a buffering effect of opioid agonists. These subjects may develop coping skills to tolerate pain distress, thereby avoiding relapse in response to pain triggers. Understanding how pain creates more intense psychophysiological responses among COAP patients may lead to better treatments.

Does Opioid Tapering in Chronic Pain Patients Result in Improved Pain or Same Pain vs Increased Pain at Taper Completion? A Structured Evidence-Based Systematic Review

Objective

To support or refute the hypothesis that opioid tapering in chronic pain patients (CPPs) improves pain or maintains the same pain level by taper completion but does not increase pain.

Methods

Of 364 references, 20 fulfilled inclusion/exclusion criteria. These studies were type 3 and 4 (not controlled) but reported pre/post-taper pain levels. Characteristics of the studies were abstracted into tabular form for numerical analysis. Studies were rated independently by two reviewers for quality. The percentage of studies supporting the above hypothesis was determined.

Results

No studies had a rejection quality score. Combining all studies, 2,109 CPPs were tapered. Eighty percent of the studies reported that by taper completion pain had improved. Of these, 81.25% demonstrated this statistically. In 15% of the studies, pain was the same by taper completion. One study reported that by taper completion, 97% of the CPPs had improved or the same pain, but CPPs had worse pain in 3%. As such, 100% of the studies supported the hypothesis. Applying the Agency for Health Care Policy and Research Levels of Evidence Guidelines to this result produced an A consistency rating.

Conclusions

There is consistent type 3 and 4 study evidence that opioid tapering in CPPs reduces pain or maintains the same level of pain. However, these studies represented lower levels of evidence and were not designed to test the hypothesis, with the evidence being marginal in quality with large amounts of missing data. These results then primarily reveal the need for controlled studies (type 2) to address this hypothesis.

Withdrawal-associated injury site pain (WISP): a descriptive case series of an opioid cessation phenomenon

Supplemental Digital Content is Available in the Text.

This descriptive case series among adults documents that pain can return temporarily at healed, previously pain-free injury sites during acute opioid withdrawal.

Withdrawal pain can be a barrier to opioid cessation. Yet, little is known about old injury site pain in this context. We conducted an exploratory mixed-methods descriptive case series using a web-based survey and in-person interviews with adults recruited from pain and addiction treatment and research settings. We included individuals who self-reported a past significant injury that was healed and pain-free before the initiation of opioids, which then became temporarily painful upon opioid cessation—a phenomenon we have named withdrawal-associated injury site pain (WISP). Screening identified WISP in 47 people, of whom 34 (72%) completed the descriptive survey, including 21 who completed qualitative interviews. Recalled pain severity scores for WISP were typically high (median: 8/10; interquartile range [IQR]: 2), emotionally and physically aversive, and took approximately 2 weeks to resolve (median: 14; IQR: 24 days). Withdrawal-associated injury site pain intensity was typically slightly less than participants' original injury pain (median: 10/10; IQR: 3), and more painful than other generalized withdrawal symptoms which also lasted approximately 2 weeks (median: 13; IQR: 25 days). Fifteen surveyed participants (44%) reported returning to opioid use because of WISP in the past. Participants developed theories about the etiology of WISP, including that the pain is the brain's way of communicating a desire for opioids. This research represents the first known documentation that previously healed, and pain-free injury sites can temporarily become painful again during opioid withdrawal, an experience which may be a barrier to opioid cessation, and a contributor to opioid reinitiation.

Comparing Pain and Depressive Symptoms of Chronic Opioid Therapy Patients Receiving Dose Reduction and Risk Mitigation Initiatives With Usual Care

Dose reduction and risk mitigation initiatives have been recommended to reduce opioid-related risks among patients receiving chronic opioid therapy (COT), but questions remain over whether these initiatives worsen pain control and quality of life. In 2014 to 2015, we interviewed 1,588 adult COT patients within a health care system in Washington State and compared those who received dose reduction and risk mitigation initiatives in primary care clinics (intervention) with patients in comparable health care settings without initiatives (control). The primary outcomes were pain assessed using the pain, enjoyment, and general activity (PEG) scale, a 3-item scale to assess global pain intensity and interference, with secondary measures including depression (Patient Health Questionnaire-8 scale). Generalized estimating equations for linear regression models were used to estimate differences in mean scores between intervention and control sites. Estimated differences, adjusted for patient characteristics and weighted for nonresponse, between patients at intervention and control clinics were not clinically significant for the PEG (-.03, 95% confidence interval = -.25 to .19) or Patient Health Questionnaire-8 (-.64, 95% confidence interval = -1.19 to -.08). We found no evidence that COT patients in clinics with dose reduction and risk mitigation initiatives had clinically meaningful differences in pain intensity, interference with activities and enjoyment of life, or depressive symptoms compared with control health care settings.

PERSPECTIVE

This article evaluates the effect of dose reduction and risk mitigation initiatives, such as those recently recommended by the Centers for Disease Control and Prevention, to reduce risks associated with COT on global pain and interference, depressive symptoms, and perceived pain relief and bothersomeness of side effects.

Chronic Pain in Neurosurgery

This review includes a summary of contemporary theories of pain processing and advocates a multimodal analgesia approach for providing perioperative care. A summary of various medication classes and anesthetic techniques is provided that highlights evidence emerging from neurosurgical literature. This summary covers opioid management, acetaminophen, nonsteroidal antiinflammatories, ketamine, lidocaine, dexmedetomidine, corticosteroids, gabapentin, and regional anesthesia for neurosurgery. At present, there is not enough investigation into these areas to describe best practices for treating or preventing chronic pain in neurosurgery; but providers can identify a wider range of options available to personalize perioperative care strategies.

Patient Perspectives Associated with Intended Duration of Buprenorphine Maintenance Therapy

Patients with opioid use disorders frequently discontinue opioid maintenance therapy (OMT) prematurely, reducing retention and possibly limiting the efficacy of OMT. The current study is a cross-sectional survey of patients (N=69) enrolled in buprenorphine maintenance therapy (BMT). We examined patient demographics, BMT characteristics (e.g., dose, time in BMT), and patient perspectives regarding intended duration of BMT. In addition, patients' reasons for continuing or discontinuing BMT were investigated. Results revealed that the majority (82%) of participants reported wanting to continue BMT for at least 12months. Age at first drug use, time in BMT, concern about pain, and concern about relapse were all positively associated with intended duration of BMT. The following were negatively associated with intended duration of BMT: recent discussion with a treatment provider about BMT discontinuation, prior attempt to discontinue BMT, concern about withdrawal symptoms, experiencing pleasurable effects from taking buprenorphine, and perceived conflicts of BMT with life, work, or school obligations. The most common reasons for wanting to continue BMT included concerns about withdrawal symptoms, relapse, and pain. Although preliminary, the findings highlight key issues with regard to patients' perspectives of BMT. The results of this study provide information that may be useful in improving OMT programs and treatment outcomes.

Tapering Long-term Opioid Therapy in Chronic Noncancer Pain: Evidence and Recommendations for Everyday Practice

Increasing concern about the risks and limited evidence supporting the therapeutic benefit of long-term opioid therapy for chronic noncancer pain are leading prescribers to consider discontinuing the use of opioids. In addition to overt addiction or diversion, the presence of adverse effects, diminishing analgesia, reduced function and quality of life, or the absence of progress toward functional goals can justify an attempt at weaning patients from long-term opioid therapy. However, discontinuing opioid therapy is often hindered by patients' psychiatric comorbidities and poor coping skills, as well as the lack of formal guidelines for the prescribers. The aim of this article is to review the existing literature and formulate recommendations for practitioners aiming to discontinue long-term opioid therapy. Specifically, this review aims to answer the following questions: What is an optimal opioid tapering regimen? How can the risks involved in a taper be managed? What are the alternatives to an opioid taper? A PubMed literature search was conducted using the keywords chronic pain combined with opioid withdrawal, taper, wean and detoxification. Six hundred ninety-five documents were identified and screened; 117 were deemed directly relevant and are included. On the base of this literature review, this article proposes evidence-based recommendations and expert-based suggestions for clinical practice. Furthermore, areas of lack of evidence are identified, providing opportunities for further research.

Chronic and acute pain and pain management for patients in methadone maintenance treatment

BACKGROUND AND OBJECTIVES

Many individuals receiving methadone maintenance treatment (MMT) for opioid addiction also require treatment for acute or chronic pain, and the presence of pain is known to have a negative impact on patient health and function. However, effective pain management in this population is complicated by many factors, including heightened pain sensitivity, high opioid tolerance, illicit substance use, and variable cross-tolerance to opioid pain medications. This article reviews the recent literature on acute and chronic pain among, and pain treatment of, patients receiving MMT for opioid addiction and discusses the implications for effective pain management. Acute pain management among women maintained on methadone during and after labor and delivery is also discussed, as well as common concerns held by patients and providers about appropriate pain management strategies in the context of methadone maintenance and addiction treatment.

METHODS

One hundred nine articles were identified in a PubMed/MEDLINE electronic database search using the following search terms: methadone, methadone maintenance, methadone addiction, pain, pain management, chronic pain, and acute pain. Abstracts were reviewed for relevance, and additional studies were extracted from the reference lists of articles identified in the original search.

RESULTS

The pain sensitivity and pain responses of MMT patients differ significantly from those of patients not maintained on opioids, and few data are available to guide patient care.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

Rigorous studies are needed to identify and evaluate effective pain management approaches for this unique patient population and to improve patient treatment outcomes.

Longitudinal observation of changes in pain sensitivity during opioid tapering in patients with chronic low-back pain

OBJECTIVE

  Several studies have shown that exposure to opioids for short or long periods alters pain sensitivity. Little is known about changes in pain sensitivity during and after tapering of long-term prescribed opioid treatment in chronic low-back pain (cLBP) patients.

DESIGN

  The goal of this prospective longitudinal study was to investigate pain sensitivity in a homogeneous patient population (cLBP patients only) after tapering of long-term (17 months) opioid use and to monitor the changes in pain sensitivity for 6 months.

METHODS

  Pain sensitivity (thermal sensation and thermal pain thresholds in low back and nondominant hand) was measured by quantitative sensory testing (QST) at 1 day before (T1), 3 weeks after (T2), and 6 months after the start of opioid tapering (T3) in 35 patients with both cLBP and opioid medication (OP), 35 opioid-naïve cLBP patients (ON), and 28 individuals with neither pain nor opioid intake (HC).

RESULTS

  Significant differences in heat pain thresholds were found among the three groups at all three time points (T1: P=0.001, T2: P=0.015, T3: P=0.008), but not between the two patient groups. OP patients showed lower cold pain thresholds at T2 than ON patients and HC. At T3, the heat pain thresholds of OP patients still remained lower than HC (P=0.017), while those of ON patients were normalized.

CONCLUSIONS

  Our findings suggest that long-term use of opioids does not reduce pain sensitivity in cLBP patients; opioid tapering may induce brief hyperalgesia that can be normalized over a longer period.

Randomized double-blind placebo controlled crossover study of acetaminophen, ibuprofen, acetaminophen/hydrocodone, and placebo for the relief of pain from a standard painful stimulus

OBJECTIVES

The objective was to compare subjects' change in perceived acute pain from an identical painful stimulus after receiving three separate, commonly used pain medications and placebo.

METHODS

This was an institutional review board-approved, randomized, double-blind crossover study of healthy human volunteers. Subjects received 1000 mg of acetaminophen, 800 mg of ibuprofen, the combination of 650 mg of acetaminophen with 10 mg of hydrocodone, or placebo (800 mg of lactose) in a randomized order over four separate occasions each 1 week apart. Prior to receiving the drug on each study day, subjects placed their nondominant hand in a bath of 0 degrees C water for 45 seconds. The bath was divided into two sections; the larger was the reservoir of cooled water monitored at 0 degrees C, and the other half was filled from constant overflow. Water drained from the overflow section into the cooling unit and was then pumped up into the base of the reservoir through a diffusion grid. Subjects completed a 100-mm visual analog scale (VAS) representing perceived pain during the exposure. The cold water exposure and VAS were repeated 1 hour after receiving the study drug, and then subjects were observed for side effects for 4 hours. Data were compared using descriptive statistics, 95% confidence intervals (CIs), and repeated-measures analysis of variance (ANOVA).

RESULTS

Twenty-five subjects were enrolled. The mean VAS preexposure was 56.9 mm (+/-15.1 mm; range = 5 to 92 mm). The mean decrease in VAS after receiving the study drug for acetaminophen was 10.2% (95% CI = -1.4 to 20.4), for ibuprofen was -6.6% (95% CI = -16.5 to 3.20), for acetaminophen/hydrocodone was 9.5% (95% CI = 1.4 to 20.4), and for placebo was -6.9% (95% CI = -15.2 to 1.4). The range in change in pain scores for all agents was -91.3% to 57.6%. Mild side effects (nausea, dizziness, or somnolence) were reported in 11 subjects (44%) after receiving acetaminophen/hydrocodone; no other side effects were reported.

CONCLUSIONS

There was a wide range of changes in pain scores from this identical painful stimulus after receiving the study medications. Acetaminophen and acetaminophen/hydrocodone resulted in a similar decrease in pain (10.2 and 9.5%), while ibuprofen and placebo had a similar lack of effect (-6.6 and -6.9%). Forty-four percent of subjects receiving acetaminophen/hydrocodone reported mild side effects; no other side effects were seen. In this noninflammatory pain model, the VAS is not able to distinguish differences in pain relief between acetaminophen and acetaminophen/hydrocodone or ibuprofen and placebo.