Transdermal buprenorphine for moderate chronic noncancer pain syndromes

Analgesic Effect of Buprenorphine for Chronic Noncancer Pain: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Buprenorphine is a partial agonist at the µ-opioid receptor and an antagonist at the delta and kappa opioid receptors. It has high affinity and low intrinsic activity at the µ-opioid receptor. Buprenorphine demonstrates no ceiling effect for clinical analgesia, but demonstrates this for respiratory depression and euphoria. It may provide effective analgesia while producing less adverse effects, making it a promising opioid analgesic. A systematic review and meta-analysis were performed to examine the analgesic efficacy of buprenorphine for patients with chronic noncancer pain.

METHODS

PubMed, MEDLNE, Embase, and the Cochrane Library were searched up to January 2022. Randomized controlled trials were included if they compared buprenorphine versus placebo or active analgesic in patients with chronic noncancer pain, where pain score was an outcome. Nonrandomized controlled trials, observational studies, qualitative studies, case reports, and commentaries were excluded. Two investigators independently performed the literature search, study selection, and data collection. A random-effects model was used. The primary outcome was the effect of buprenorphine on pain intensity in patients with chronic noncancer pain based on standardized mean difference (SMD) in pain score. Quality of evidence was assessed using the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Two separate literature searches were conducted for patients with and without opioid use disorder (OUD). Only one study met the search criteria for those with OUD. Fourteen randomized controlled trials were included for those without OUD. Buprenorphine was associated with reduced pain score (SMD = -0.368, P < .001, I 2 = 89.37%) compared to placebo or active analgesic. Subgroup meta-analyses showed statistically significant differences in favor of buprenorphine versus placebo (SMD = -0.404, P < .001), for chronic low back pain (SMD = -0.383, P < .001), when administered via the transdermal route (SMD = -0.572, P = .001), via the buccal route (SMD = -0.453, P < .001), with length of follow-up lasting <12 weeks (SMD = -0.848, P < .05), and length of follow-up lasting 12 weeks or more (SMD = -0.415, P < .001). There was no significant difference when compared to active analgesic (SMD = 0.045, P > .05). Quality of evidence was low to moderate.

CONCLUSIONS

Buprenorphine was associated with a statistically significant and small reduction in pain intensity compared to placebo. Both the transdermal and buccal routes provided pain relief. There was more evidence supporting its use for chronic low back pain.

Current and Future Therapeutic Options in Pain Management: Multi-mechanistic Opioids Involving Both MOR and NOP Receptor Activation

Opioids are widely used in chronic pain management, despite major concerns about their risk of adverse events, particularly abuse, misuse, and respiratory depression from overdose. Multi-mechanistic opioids, such as tapentadol and buprenorphine, have been widely studied as a valid alternative to traditional opioids for their safer profile. Special interest was focused on the role of the nociceptin opioid peptide (NOP) receptor in terms of analgesia and improved tolerability. Nociceptin opioid peptide receptor agonists were shown to reinforce the antinociceptive effect of mu opioid receptor (MOR) agonists and modulate some of their adverse effects. Therefore, multi-mechanistic opioids involving both MOR and NOP receptor activation became a major field of pharmaceutical and clinical investigations. Buprenorphine was re-discovered in a new perspective, as an atypical analgesic and as a substitution therapy for opioid use disorders; and buprenorphine derivatives have been tested in animal models of nociceptive and neuropathic pain. Similarly, cebranopadol, a full MOR/NOP receptor agonist, has been clinically evaluated for its potent analgesic efficacy and better tolerability profile, compared with traditional opioids. This review overviews pharmacological mechanisms of the NOP receptor system, including its role in pain management and in the development of opioid tolerance. Clinical data on buprenorphine suggest its role as a safer alternative to traditional opioids, particularly in patients with non-cancer pain; while data on cebranopadol still require phase III study results to approve its introduction on the market. Other bifunctional MOR/NOP receptor ligands, such as BU08028, BU10038, and AT-121, are currently under pharmacological investigations and could represent promising analgesic agents for the future.

An Italian Expert Consensus on the Use of Opioids for the Management of Chronic Non-Oncological Pain in Clinical Practice: Focus on Buprenorphine

Purpose

The aim of the present work was to evaluate the knowledge and prescriptive habits of clinicians involved in the management of chronic non cancer pain (CNCP), with a special focus on the use of opioids.

Methods

A Delphi method was used. A Board of specialists elaborated and discussed a series of statements, based on available literature and personal clinical expertise, about particularly controversial topics on pain pathophysiology and treatment. A Panel of experts in the field of pain management, selected by the Board, was invited to vote the proposed statements, indicating the level of agreement on a 5-point Likert scale (1: strongly disagree; 2: disagree; 3: partially agree; 4: agree; 5: strongly agree). The threshold for consensus was set at minimum 66.6% of the number of respondents with a level of agreement ≥4 (Agree or Strongly agree).

Results

The Board included 5 pain therapists, 1 pharmacologist and 1 methodology expert and drew up a total of 36 statements (for a total of 40 requested answers)”. A total of 100 clinicians were included in the Expert Panel. Respondents were 89 (89%). Consensus was achieved for 32 out of 40 answers. Most of the lack of consensus was recorded for statements regarding opioids use, and resulted from a low level of agreement (3 on the Likert scale), suggesting a neutral position deriving from a lack of knowledge rather than a strong contrary opinion.

Conclusion

Most of the proposed items reached consensus, suggesting a generally homogeneous approach to CNCP management. However, the lack of consensus recorded for several items regarding opioid use confirms the need to fill important gaps in the knowledge of available agents. A clear explanation of the peculiar pharmacological properties of drugs associated with potential clinical advantages (such as buprenorphine) will help optimize pain treatment in both primary care and hospital settings and improving pain control in CNCP patients.

Editorial for the special issue of the Chinese Association for the Study of Pain

The Ministry of Health of China officially issued a document, adding the first level diagnosis and treatment discipline “Algology” in the list of diagnosis and treatment subjects of medical institutions on July 16, 2007. As the most important pain academic organization in China, the Chinese Association for the Study of Pain has made outstanding contributions in promoting the development of pain discipline and in establishing pain standards and disease diagnosis and treatment guidelines. In this special issue, under the leadership of Yan-Qing Liu, Chairman of the 7^th Committee of the Chinese Association for the Study of Pain, nine consensus and one guideline were included.

Expert consensus of the Chinese Association for the Study of Pain on pain treatment with the transdermal patch

Chronic pain lasting more than 3 mo, or even several years can lead to disability. Treating chronic pain safely and effectively is a critical challenge faced by clinicians. Because administration of analgesics through oral, intravenous or intramuscular routes is not satisfactory, research toward percutaneous delivery has gained interest. The transdermal patch is one such percutaneous delivery system that can deliver drugs through the skin and capillaries at a certain rate to achieve a systemic or local therapeutic effect in the affected area. It has many advantages including ease of administration and hepatic first pass metabolism avoidance as well as controlling drug delivery, which reduces the dose frequency and side effects. If not required, then the patch can be removed from the skin immediately. The scopolamine patch was the first transdermal patch to be approved for the treatment of motion sickness by the Food and Drug Administration in 1979. From then on, the transdermal patch has been widely used to treat many diseases. To date, no guidelines or consensus are available on the use of analgesic drugs through transdermal delivery. The pain branch of the Chinese Medical Association, after meeting and discussing with experts and based on clinical evidence, developed a consensus for promoting and regulating standard use of transdermal patches containing analgesic drugs.

Pain management in patients with chronic kidney disease and end-stage kidney disease

PURPOSE OF REVIEW

This review evaluates current recommendations for pain management in chronic kidney disease (CKD) and end-stage kidney disease (ESKD) with a specific focus on evidence for opioid analgesia, including the partial agonist, buprenorphine.

RECENT FINDINGS

Recent evidence supports the use of physical activity and other nonpharmacologic therapies, either alone or with pharmacological therapies, for pain management. Nonopioid analgesics, including acetaminophen, topical analgesics, gabapentinoids, serotonin-norepinephrine reuptake inhibitors, and TCA may be considered based on pain cause and type, with careful dose considerations in kidney disease. NSAIDs may be used in CKD and ESKD for short durations with careful monitoring. Opioid use should be minimized and reserved for patients who have failed other therapies. Opioids have been associated with increased adverse events in this population, and thus should be used cautiously after risk/benefit discussion with the patient. Opioids that are safer to use in kidney disease include oxycodone, hydromorphone, fentanyl, methadone, and buprenorphine. Buprenorphine appears to be a promising and safer option due to its partial agonism at the mu opioid receptor.

SUMMARY

Pain is poorly managed in patients with kidney disease. Nonpharmacological and nonopioid analgesics should be first-line approaches for pain management. Opioid use should be minimized with careful monitoring and dose adjustment.

The association between initial opioid type and long-term opioid use after hip fracture surgery in elderly opioid-naïve patients

Objectives Long-term opioid use after hip fracture surgery has been demonstrated in previously opioid-naïve elderly patients. It is unknown if the opioid type redeemed after hip surgery is associated with long-term opioid use. The aim of this study was to examine the association between the opioid type redeemed within the first three months after hip fracture surgery and opioid use 3-12 months after the surgery. Methods A nationwide population-based cohort study was conducted using data from Danish health registries (2005-2015). Previously opioid-naïve patients registered in the Danish Multidisciplinary Hip Fracture Registry, aged ≥65 years, who redeemed ≥1 opioid prescription within three months after the surgery, were included. Long-term opioid use was defined as ≥1 redeemed prescription within each of three three-month periods within the year after hip fracture surgery. The proportion with long-term opioid use after surgery, conditioned on nine-month survival, was calculated according to opioid types within three months after surgery. Adjusted odds ratios (aOR) for different opioid types were computed by logistic regression analyses with 95% confidence intervals (CI) using morphine as reference. Subgroup analyses were performed according to age, comorbidity and calendar time before and after 2010. Results The study included 26,790 elderly, opioid-naïve patients with opioid use within three months after hip fracture surgery. Of these patients, 21% died within nine months after the surgery. Among the 21,255 patients alive nine months after surgery, 15% became long-term opioid users. Certain opioid types used within the first three months after surgery were associated with long-term opioid use compared to morphine (9%), including oxycodone (14%, aOR; 1.76, 95% CI 1.52-2.03), fentanyl (29%, aOR; 4.37, 95% CI 3.12-6.12), codeine (13%, aOR; 1.55, 95% CI 1.14-2.09), tramadol (13%, aOR; 1.56, 95% CI 1.35-1.80), buprenorphine (33%, aOR; 5.37, 95% CI 4.14-6.94), and >1 opioid type (27%, aOR; 3.83, 95% CI 3.31-4.44). The proportion of long-term opioid users decreased from 18% before 2010 to 13% after 2010. Conclusions The findings suggest that use of certain opioid types after hip fracture surgery is more associated with long-term opioid use than morphine and the proportion initiating long-term opioid use decreased after 2010. The findings suggest that some elderly, opioid-naïve patients appear to be presented with untreated pain conditions when seen in the hospital for a hip fracture surgery. Decisions regarding the opioid type prescribed after hospitalization for hip fracture surgery may be linked to different indication for pain treatment, emphasizing the likelihood of careful and conscientious opioid prescribing behavior.

The utilization of buprenorphine in chronic pain

Reclassification of chronic pain as a disease may be helpful because patients with chronic pain require significant treatment and rehabilitation with a clear diagnosis. This can help address critical factors including suffering, quality of life, participation, and with family and social life, which continue to become more important in evaluating the quality of the health care we give our patients today. During the past decade of the opioid epidemic, methadone was the primary treatment for opioid addiction until buprenorphine was approved. Buprenorphine's high-affinity partial agonist properties make it a good alternative to methadone due to lower abuse potential and safer adverse effect profile while maintaining significant efficacy. Expanded out-patient prescribing options have allowed physician and physician extenders such as physician assistants and nurse practitioners to treat these patients that otherwise would have been required to utilize methadone. With unique pharmacological properties, buprenorphine is a safe and effective analgesic for chronic pain. The literature for buprenorphine shows great potential for its utilization in the treatment of chronic pain.

Naldemedine: A New Option for OIBD

Opioid-induced bowel dysfunction (OIBD) is a common complication in long-term opioid users and abusers. It is a burdensome condition, which significantly limits quality of life and is associated with increasing health costs. OIBD affects up to 60% of patients with chronic non-cancer pain and over 80% of patients suffering from cancer pain and is one of the conditions of the most common symptoms associated with opioid maintenance. Given the continued use of opioids for chronic pain management in appropriate patients, OIBD is likely to persist in clinical practice in the coming years. We will herein review its underlying pathophysiological mechanisms and the available treatments. In the last years, pharmaceutical research has focused on the opportunity of targeting peripheral mu-opioid receptors without affecting their analgesic activity in the central nervous system, and several peripherally acting mu-opioid receptors antagonists (PAMORAs) drugs have been approved. We will mainly focus on naldemedine, discussing its pharmacological properties, its clinical efficacy and side effects. Head-to-head comparisons between naldemedine and the other PAMORAs are not available yet, but some considerations will be discussed based on the pharmacological and clinical data. As a whole, the available data suggest that naldemedine is a valid treatment option for OIBD, as it is a well-tolerated drug that alleviates constipation without affecting analgesia or causing symptoms of opioid withdrawal.

Assessing and Treating Chronic Pain in Patients with End-Stage Renal Disease

Pain is one of the most common symptoms among patients with end-stage renal disease (ESRD), and is often under recognized and not adequately managed in hemodialysis (HD) patients. Barriers to adequate pain management include poor awareness of the problem, insufficient medical education, fears of possible drug-related side effects, and common misconceptions about the inevitability of pain in elderly and HD patients. Caregivers working in HD should be aware of the possible consequences of inadequate pain assessment and management. Common pain syndromes in HD patients include musculoskeletal diseases and metabolic neuropathies, associated with typical intradialytic pain. Evaluating the etiology, nature, and intensity of pain is crucial for choosing the correct analgesic. A mechanism-based approach to pain management may result in a better outcome. Pharmacokinetic considerations on clearance alterations and possible toxicity in patients with ESRD should drive the right analgesic prescription. Comorbidities and polymedications may increase the risk of drug-drug interactions, therefore drug metabolism should be taken into account when selecting analgesic drugs. Automedication is common among HD patients but should be avoided to reduce the risk of hazardous drug administration. Further research is warranted to define the efficacy and safety of analgesic drugs and techniques in the context of patients with ESRD as generalizing information from studies conducted in the general population could be inappropriate and potentially dangerous. A multidisciplinary approach is recommended for the management of complex pain syndromes in frail patients, such as those suffering from ESRD.

Testosterone deficiency in non-cancer opioid-treated patients

PURPOSE

The use of opioids in patients with chronic non-cancer pain is common and can be associated with opioid-induced androgen deficiency (OPIAD) in men. This review aims to evaluate the current literature regarding the prevalence, clinical consequence and management of OPIAD.

METHODS

A database search was performed in Medline, Embase and Cochrane using terms such as "analgesics", "opioids" and "testosterone". Relevant literature from January 1969 to March 2018 was evaluated.

RESULTS

The prevalence of patients with OPIAD ranges from 19 to 86%, depending on the criteria for diagnosis of hypogonadism. The opioid-induced suppression of gonadotropin-releasing and luteinizing hormones represents the main important pathogenetic mechanisms. OPIAD has significant negative clinical consequences on sexual function, mood, bone density and body composition. In addition, OPIAD can also impair pain control leading to hyperalgesia, which can contribute to sexual dysfunction and mood impairment.

CONCLUSIONS

OPIAD is a common adverse effect of opioid treatment and contributes to sexual dysfunction, impairs pain relief and reduces overall quality of life. The evaluation of serum testosterone levels should be considered in male chronic opioid users and the decision to initiate testosterone treatment should be based on the clinical profile of individuals, in consultation with the patient.