Clinical update on the pharmacology, efficacy and safety of transdermal buprenorphine

Understanding osteoporotic pain and its pharmacological treatment

Osteoporosis, a disorder that affects millions of people worldwide, is characterized by decreased bone mass and microstructural alterations giving rise to an increased risk of fractures. Osteoporotic fractures can cause acute and chronic pain that mainly affects elderly patients with multiple comorbidities and commonly on different drug regimens. The aim of this paper is to summarize the pathogenesis and systemic treatment of osteoporotic pain. This narrative review summarizes the main pathogenetic aspects of osteoporotic pain and the cornerstones of its treatment. Osteoporotic fractures induce both acute and chronic nociceptive and neuropathic pain. Central sensitization seems to play a pivotal role in developing and maintaining chronicity of post-fracture pain in osteoporosis. Antiosteoporosis drugs are able to partially control pain, but additional analgesics are always necessary for pain due to bone fractures. Nonsteroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors reduce acute pain but with a poor effect on the chronic neuropathic component of pain and with relevant side effects. Opioid drugs can control the whole spectrum of acute and chronic bone pain, but they differ with respect to their efficacy on neuropathic components, their tolerability and safety. Chronic pain after osteoporotic fractures requires a multifaceted approach, which includes a large spectrum of drugs (antiosteoporosis treatment, acetaminophen, NSAIDs, selective COX-2 inhibitors, weak and strong opioids) and non-pharmacological treatment. Based on a better understanding of the pathogenesis of osteoporotic and post-fracture pain, a guided stepwise approach to post-fracture osteoporotic pain will also better meet the needs of these patients.

Tolerability of buprenorphine transdermal system in nursing home patients with advanced dementia: a randomized, placebo-controlled trial (DEP.PAIN.DEM)

Purpose

Buprenorphine transdermal system is increasingly prescribed in people with advanced dementia, but no clinical trial has investigated the safety and factors associated with discontinuation due to adverse events in this population.

Patients and methods

One hundred sixty-two people with advanced dementia and significant depression from 47 nursing homes were included and randomized to active analgesic treatment (acetaminophen/buprenorphine) or identical placebo for 13 weeks. In this secondary analysis, the main outcomes were time to and reasons for discontinuation of buprenorphine due to adverse events. Change in daytime activity as measured by actigraphy was a secondary outcome.

Results

Of the 44 patients who received active buprenorphine 5 µg/hour, 52.3% (n=23) discontinued treatment due to adverse events compared to 13.3% (6 of 45) in the placebo group (p<0.001). Psychiatric and neurological adverse events were the most frequently reported causes of discontinuation (69.6%, n=16). Concomitant use of antidepressants significantly increased the risk of discontinuation (HR 23.2, 95% CI: 2.95–182, p=0.003). Adjusted for age, sex, cognitive function, pain and depression at baseline, active buprenorphine was associated with 24.0 times increased risk of discontinuation (Cox model, 95% CI: 2.45–235, p=0.006). Daytime activity dropped significantly during the second day of active treatment (−21.4%, p=0.005) and decreased by 12.9% during the first week (p=0.053).

Conclusion

Active buprenorphine had significantly higher risk of discontinuation compared with placebo in people with advanced dementia and depression, mainly due to psychiatric and neurological adverse events. Daytime activity dropped significantly during the first week of treatment. Concomitant use of antidepressants further reduced the tolerability of buprenorphine.

Transdermal buprenorphine for moderate chronic noncancer pain syndromes

Introduction: Chronic noncancer pain has remained a challenging clinical problem. Opioid analgesics are effective, but they are known to be associated with opioid use disorder and potentially treatment-limiting side effects. Buprenorphine is a Schedule III synthetic opioid in the USA with a chemical structure similar to that of morphine but with a longer duration of action, greater potency, and other unique pharmacological attributes. Its role in treatment of chronic noncancer pain may be broader than currently thought.Areas covered: The pharmacokinetics, pharmacodynamics, clinical efficacy, and safety profile of transdermal buprenorphine in moderate chronic noncancer pain syndromes patients will be discussed.Expert commentary: Buprenorphine offers effective analgesia in the form of a Schedule III drug (rather than Schedule II such as oxycodone or morphine) and transdermal buprenorphine is a convenient, accepted, around-the-clock pain reliever. Its lower potential for abuse should make it a more desirable pain reliever but many payers do not reimburse buprenorphine, driving prescribers and their patients to generic versions of the riskier Schedule II oral opioids such as oxycodone and morphine.

What Parenteral Opioids to Use in Face of Shortages of Morphine, Hydromorphone, and Fentanyl

Parenteral potent opioid availability is becoming an issue in acute pain management. Two opioids, nalbuphine and buprenorphine, are available which can be substituted for hydromorphone, fentanyl, and morphine. There are advantages and disadvantages in using these 2 opioids which are discussed, and potential dosing strategies are outlined.

Buprenorphine and pain treatment in pediatric patients: an update

Introduction

The usual management of moderate to severe pain is based on the use of opioids. Buprenorphine (BPN) is an opioid with an analgesic potency 50 times greater than that of morphine. It is widely used in various pain models and has demonstrated efficacy and safety in adult patients; however, there are insufficient clinical trials in pediatric populations.

Purpose

The aim of this study was to perform an updated meta-analysis on the implementation of BPN in the treatment of pain in the pediatric population.

Methods

A bibliographic search was carried out in different biomedical databases to identify scientific papers and clinical trials with evidence of BPN use in children and adolescents.

Results

A total of 89 articles were found, of which 66 were selected. Analysis of these items revealed additional sources, and the final review included a total of 112 publications.

Conclusion

Few studies were found regarding the efficacy and safety of BPN use in children. In recent years, the use of this drug in the pediatric population has become widespread, so it is imperative to perform clinical trials and pharmacological and pharmacovigilance studies, which will allow researchers to develop dosage schemes based on the evidence and minimize the risk of adverse effects.

Efficacy of transdermal buprenorphine patch on post-operative pain relief after elective spinal instrumentation surgery

BACKGROUND AND AIMS

Transdermal buprenorphine patch (TDB) is increasingly used for chronic pain management because of non-invasive dosing, longer duration of action and minimal side effects. However its role in acute post-operative pain management for spinal instrumentation surgery is not well established. The aim of this study was to evaluate the analgesic efficacy of buprenorphine patch for postoperative pain relief in patients undergoing spinal instrumentation surgery.

METHODS

In this randomised, placebo-controlled, double-blinded, prospective study, 70 adult patients undergoing elective spinal instrumentation surgery were randomly allocated into two groups-TDB Group (buprenorphinepatch) and TDP Group (placebo patch). Time to first rescue analgesic requirement was the primary outcome. All patients also were monitored for total rescue analgesic requirement, drug-related adverse effect and haemodynamic status till 48 h after surgery. Statistical analysis was carried out using student independent t-test if normally distributed or with Mann-Whitney U-test if otherwise.

RESULTS

Time to first post-operative rescue analgesic (tramadol) requirement was much delayed in TDB Group than TDP Group (708.0 ± 6.98 min vs 54 ± 0.68 min, P < 0.001) and the total tramadol requirement was higher in TDB Group (490.60 ± 63.09 averagevs. 162.93 ± 63.91 mg, P < 0.001). Intra-and post-operative haemodynamic status was also stable in TDB Group without any adverse event.

CONCLUSION

A TDB patch (10 μg/hour) applied 24 hours before surgery can be used as a postoperative analgesic for lumber fixation surgery without any drug-related adverse effect.

Transdermal buprenorphine and fentanyl patches in cancer pain: a network systematic review

Treatment of cancer pain is generally based on the three-step World Health Organization (WHO) pain relief ladder, which utilizes a sequential approach with drugs of increasing potency. Goals of pain management include optimization of analgesia, optimization of activities of daily living, minimization of adverse effects, and avoidance of aberrant drug taking. In addition, it is recommended that analgesic regimens are individualized and simplified to help ensure patient compliance and should provide the least invasive, easiest, and safest route of opioid administration to ensure adequate analgesia. Buprenorphine and fentanyl are two opioids available for the relief of moderate-to-severe cancer pain. Available clinical data regarding the transdermal (TD) formulations of these opioids and the extent to which they fulfill the recommendations mentioned earlier are systematically reviewed, with the aim of providing additional information for oncologists and pain specialists regarding their comparative use. Due to lack of studies directly comparing TD buprenorphine with TD fentanyl, data comparing these with other step-3 opioids are also evaluated in a network fashion.

Effectiveness and tolerability of transdermal buprenorphine patches: a multicenter, prospective, open-label study in Asian patients with moderate to severe chronic musculoskeletal pain

BACKGROUND

We examined the effectiveness and tolerability of transdermal buprenorphine (TDB) treatment in real-world setting in Asian patients with musculoskeletal pain.

METHODS

This was an open-label study conducted in Hong Kong, Korea, and the Philippines between June 2013 and April 2015. Eligible patients fulfilled the following criteria: 18 to 80 years of age; clinical diagnosis of osteoarthritis, rheumatoid arthritis, low back pain, or joint/muscle pain; chronic non-malignant pain of moderate to severe intensity (Box-Scale-11 [BS-11] pain score ≥ 4), not adequately controlled with non-opioid analgesics and requiring an opioid for adequate analgesia; and no prior history of opioid treatment. Patients started with a 5 μg/h buprenorphine patch and were titrated as necessary to a maximum of 40 μg/h over a 6-week period to achieve optimal pain control. Patients continued treatment with the titrated dose for 11 weeks. The primary efficacy endpoint was the change in BS-11 pain scores. Other endpoints included patients' sleep quality and quality of life as assessed by the 8-item Global Sleep Quality Assessment Scale (GSQA) questionnaire and the EuroQol Group 5-Dimension Self-Report Questionnaire-3 Level version (EQ-5D-3 L), respectively. Tolerability was assessed by collecting adverse events.

RESULTS

A total of 114 eligible patients were included in the analysis. The mean BS-11 score at baseline was 6.2 (SD 1.6). Following initiation of TDB, there was a statistically significant improvement in BS-11 score from baseline to visit 3 (least squares [LS] mean change: -2.27 [95% CI -2.66 to -1.87]), which was maintained till the end of the study (visit 7) (LS mean change: -2.64 [95% -3.05 to -2.23]) (p < 0.0001 for both). The proportion of patients who rated sleep quality as 'good' increased from 14.0% at baseline to 26.9% at visit 6. By visit 6, the mean EQ VAS score increased by 7.7 units (SD 17.9). There were also significant improvements in patients' levels of functioning for all EQ-5D-3 L dimensions from baseline at visit 6 (p < 0.05 for all). Seventy-eight percent of patients reported TEAEs and 22.8% of patients discontinued due to TEAEs. TEAEs were generally mild to moderate in intensity (96.5%).

CONCLUSIONS

TDB provides effective pain relief with an acceptable tolerability profile over the 11-week treatment period in Asian patients with chronic musculoskeletal pain. More studies are needed to examine the long-term efficacy and safety of TBD treatment in this patient population.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01961271 . Registered 7 October 2013 (retrospectively registered; first patient was enrolled on 28 June 2013 and last patient last visit date was 26 Apr 2015).

Use of immediate-release opioids as supplemental analgesia during management of moderate-to-severe chronic pain with buprenorphine transdermal system

Background

The buprenorphine transdermal system (BTDS) is approved in the US for the management of chronic pain. Due to its high affinity for μ-opioid receptors with a slow dissociation profile, buprenorphine may potentially displace or prevent the binding of competing μ-opioid-receptor agonists, including immediate-release (IR) opioids, in a dose-dependent manner. Health care professionals may assume that the use of IR opioids for supplemental analgesia during BTDS therapy is not acceptable.

Materials and methods

This post hoc analysis evaluated the use of IR opioids as supplemental analgesia during the management of moderate–severe chronic pain with BTDS at 52 US sites (BUP3015S, NCT01125917). Patients were categorized into IR-opioid and no-IR-opioid groups. At each visit of the extension phase, adverse events, concomitant medications, and information from the Brief Pain Inventory (BPI) were recorded.

Results

The most common supplemental IR opioids prescribed during BTDS treatment (n=354) were hydrocodone–acetaminophen and oxycodone–acetaminophen. The mean daily dose of IR opioids (morphine equivalents) for supplemental analgesia was 22 mg. At baseline, BPI – pain intensity and BPI – interference scores were higher for patients in the IR-opioid group. In both treatment groups, scores improved by week 4, and then were maintained throughout 6 months of the open-label extension trial. The incidence of treatment-emergent adverse events was similar in both groups.

Conclusion

Patients who were prescribed IR opioids reported lower scores for BPI pain intensity and pain interference to levels similar to patients receiving BTDS without IR opioids, without increasing the rate or severity of treatment-emergent adverse events. Patients prescribed concomitant use of IR opioids with BTDS had greater treatment persistence. The results of this post hoc analysis provide support for the concomitant use of IR opioids for supplemental analgesia during the management of moderate–severe chronic pain with BTDS.

Satisfaction, Adherence and Health-Related Quality of Life with Transdermal Buprenorphine Compared with Oral Opioid Medications in the Usual Care of Osteoarthritis Pain

Background

Osteoarthritis (OA) causes substantial pain and reduced health-related quality of life (HRQL). Although opioid analgesics are commonly used, the relative benefits of different opioids are poorly studied. Transdermal buprenorphine (TDB) offers an alternative to oral opioids for the treatment of moderate-to-severe chronic pain. This observational study of people with OA pain assessed satisfaction, HRQL and medication adherence.

Methods

Patients in the UK with self-reported knee and/or hip OA who had been receiving one or more of TDB, co-codamol (an oral paracetamol/codeine combination) and tramadol for at least 1 month completed an online or telephone questionnaire. Medication satisfaction scores, HRQL scores (Short-Form 36 [SF-36]), medication adherence (Morisky Medication Adherence Scale [MMAS™]), adverse events and treatment discontinuations were recorded. Linear and logistic regression models were used to compare the treatment effect of TDB with co-codamol or tramadol.

Results

Overall, 966 patients met the inclusion criteria; 701 were taking only one of the target medications (TDB: 85; co-codamol: 373; tramadol: 243). The largest age group was 50–59 years and 76.0 % of patients were female. The TDB group was younger, with more male patients, therefore the statistical models were adjusted for age and sex. Medication satisfaction scores were significantly higher in the TDB group than the other two groups (TDB vs. co-codamol: 3.56, 95 % confidence interval [CI] 1.90–6.68, p < 0.0001; TDB vs. tramadol: 3.22, 95 % CI 1.67–6.20, p = 0.0005). Physical Component Summary scores for HRQL and mean adherence were also higher in the TDB group, while Mental Component Summary HRQL scores were similar across the three groups.

Conclusions

Patients with knee and/or hip OA pain treated with TDB were more satisfied and more adherent with their medication, and reported higher Physical Component Summary HRQL scores than those treated with co-codamol or tramadol, although demographic differences were observed between groups.

Electronic supplementary material

The online version of this article (doi:10.1007/s40271-016-0181-0) contains supplementary material, which is available to authorized users.

Assessment of Transdermal Buprenorphine Patches for the Treatment of Chronic Pain in a UK Observational Study

BACKGROUND

Opioids provide effective analgesia for moderate-to-severe, chronic pain. Transdermal buprenorphine (TDB) is available in the UK as weekly, lower-dose (5-20 μg/h) patches and twice-weekly, higher dose (35-70 μg/h) patches. This prospective, observational, multicenter study of patients with various chronic pain conditions assessed the safety, perceptions, and discontinuation of treatment with TDB in a real-world, non-interventional setting (ClinicalTrials.gov study ID: NCT01225861).

METHODS

Patients aged ≥18 years who were already receiving or initiating treatment with TDB were recruited in the UK during routine clinical visits and were followed for 6 visits or 9 months (whichever came first). Self-reported treatment adherence, patient satisfaction, and safety data were collected at each study visit.

RESULTS

Of 465 patients, 272 were already receiving 7-day TDB at the study start (TDB experienced), 146 were TDB naïve, and 47 were prescribed twice-weekly TDB. Most patients were female (72.9 %) and overweight/obese (body mass index ≥25: 75.3 %). The median age was 67 years, and the mean duration of pain was 11.1 years. Arthritis/other musculoskeletal disorders (39.6 %) were the most common causes of pain. Mild adverse events were commonly reported. Skin irritations, which were most frequent in 7-day TDB-experienced patients (45.6 %), rarely resulted in treatment discontinuation (8.8 %). Nearly all patients used TDB in accordance with treatment recommendations. Most patients reported that TDB was 'effective'/'very effective' at relieving pain and were 'satisfied'/'very satisfied' with TDB therapy.

CONCLUSION

In everyday clinical practice, TDB was well tolerated and patients were satisfied with their therapy. Self-reported adherence to TDB was very high, and adverse events rarely resulted in treatment discontinuation. Opportunities were identified to limit common adverse events associated with TDB.

Buprenorphine - an attractive opioid with underutilized potential in treatment of chronic pain

Despite proven clinical utility, buprenorphine has not been used widely for the treatment of chronic pain. Questions about “ceiling effect” or bell-shaped curve observed for analgesia in preclinical studies and potential withdrawal issues on combining with marketed μ-agonists continue to hinder progress in expanding full potential of buprenorphine in the treatment of cancer and noncancer pain. Mounting evidence from clinical studies and conclusions drawn by a panel of experts strongly support superior safety and efficacy profile of buprenorphine vs marketed opioids. No ceiling on analgesic effect has been reported in clinical studies. The receptor pharmacology and pharmacokinetics profile of buprenorphine is complex but unique and contributes to its distinct safety and efficacy. The buprenorphine pharmacology also allows it to be combined with other μ-receptor opioids for additivity in efficacy. Transdermal delivery products of buprenorphine have been preferred choices for the management of pain but new delivery options are under investigation for the treatment of both opioid dependence and chronic pain.

Long-term administration of high doses of transdermal buprenorphine in cancer patients with severe neuropathic pain

Background

Buprenorphine is often administered by the transdermal route (transdermal buprenorphine [TB]) in cancer patients with severe neuropathic pain. However, high doses of TB of 140 µg/h are rarely used.

Patients and methods

Three cancer patients with severe neuropathic Numeric Rating Scale (NRS) pain scores of 8–10 who were successfully treated with high doses of TB up to 140 µg/h along with other opioids and adjuvant analgesics.

Results

TB was administered for a long period of follow-up (9 months to 4 years, including 34–261 days of treatment with the dose of 140 µg/h), which allowed achievement of satisfactory analgesia (NRS 3–5) and good treatment tolerance. In all three patients, TB dose was gradually titrated from 35 to 140 µg/h, and all patients used morphine at least for some time for breakthrough and background pain management along with adjuvant analgesics. Two patients continued the treatment with TB until the end of life, and one patient is still receiving the treatment.

Conclusion

TB at doses of up to 140 µg/h in cancer patients with severe neuropathic pain seems to be effective and safe in combination with other opioids and with adjuvant analgesics, and may significantly improve patients’ quality of life. Clinical studies may explore higher than maximal 140 µg/h TB doses recommended by a manufacturer, and also in combination with other opioids and adjuvant analgesics.

Comparison between Transdermal Buprenorphine and Transdermal Fentanyl for Postoperative Pain Relief after Major Abdominal Surgeries

INTRODUCTION

Opioid is generally regarded as an important part of multimodal, perioperative analgesia, especially for moderate to severe pain. Amongst the various modes of delivery transdermal route has several potential benefits over oral and parentral administration. These include noninvasive dosing, better absorption and lack of first-pass metabolism. A transdermal drug delivery system provides steady and continuous drug delivery resulting in steady plasma concentration. Bolus dosing of systemic analgesic results in supra and sub therapeutic plasma resulting in toxic and sub analgesic plasma drug concentration. It also improves patient compliance.

MATERIALS AND METHODS

Sixty patients undergoing major abdominal surgery under GA were randomly divided in two groups (n=30). Group A received buprenorphine 10 mcg/h TDS and group B received 25 mcg/h fentanyl TDS, 6 hours prior to surgery. Patients were followed for three days for postoperative pain relief and adverse effects.

RESULTS

Baseline and demographic variables are comparable in both groups. The mean level of VAS was significantly lower in group B as compared to group A at Day 1, 2 and 3. The mean level of sedation score was significantly lower in Group B than Group A. Haemodynamic variables in both groups (SBP, DBP and HR), shows comparable values in both groups and no significant difference was observed. Five out of 30 (16.7%) patients in group A required single dose of rescue analgesic while 0 out of 30 patients (0.00%) in group B required rescue analgesic. This difference in rescue analgesic requirement in not quiet statistically significant (p-value 0.0522). Twenty percent patient in fentanyl group and 16.7% patients in buprenorphine group experienced some adverse effects. Nausea and vomiting were main side effects of the drugs. The incidence of nausea and vomiting were 6.7% and 10% in buprenorphine and fentanyl group respectively.

CONCLUSION

Fentanyl and buprenorphine TDS were effective and safe in controlling postoperative pain. Fentanyl is better than buprenorphine in this respect.

Mortality risk of opioid substitution therapy with methadone versus buprenorphine: a retrospective cohort study

BACKGROUND

Opioid dependence increases risk of premature mortality. Opioid substitution therapy with methadone or buprenorphine reduces mortality risk, especially for drug-related overdose. Clinical guidelines recommend methadone as the first line of opioid substitution therapy. We aimed to test whether buprenorphine treatment has a lower mortality risk than does methadone treatment by comparing all-cause mortality and drug-related overdose mortality at treatment induction, after in-treatment medication switches, and following treatment cessation.

METHODS

We did a retrospective cohort study of all patients with opioid dependency (n=32,033) in New South Wales, Australia, who started a methadone or buprenorphine treatment episode from Aug 1, 2001, to Dec 31, 2010, including 190,232·6 person-years of follow-up. We compared crude mortality rates (CMRs) for all-cause and drug-related overdose mortality, and mortality rate ratios (MRRs) according to age, sex, period in or out of treatment, medication type, and in-treatment switching.

FINDINGS

Patients who initiated with buprenorphine had reduced all-cause and drug-related mortality during the first 4 weeks of treatment compared with those who initiated with methadone (adjusted all-cause MRR 2·17, 95% CI 1·29-3·67; adjusted drug-related MRR 4·88, 1·73-13·69). For the remaining time on treatment, drug-related mortality risk did not differ (adjusted MRR 1·18, 95% CI 0·89-1·56), but weak evidence suggested that all-cause mortality was lower for buprenorphine than methadone (1·66, 1·40-1·96). In the 4 weeks after treatment cessation, all-cause mortality did not differ, but drug-related mortality was lower for methadone (adjusted all-cause MRR 1·12, 0·79-1·59; adjusted drug-related MRR 0·50, 0·29-0·86). Patients who switched from buprenorphine to methadone during treatment had lower mortality in the first 4 weeks of methadone treatment than matched controls who received methadone only (CMR difference 7·1 per 1000 person-years, 95% CI 0·1-14·0); no mortality difference was noted for switches from buprenorphine to methadone or for switches to either medication beyond the first 4 weeks of treatment.

INTERPRETATION

In a setting with high risk of death in the first 4 weeks of opioid substitution therapy, buprenorphine seemed to reduce mortality in this period, but little difference between buprenorphine and methadone was noted thereafter or for in-treatment switching of medications. Cross-cohort corroboration of our findings and further assessment of the stepped treatment model is warranted.

FUNDING

Australian National Health & Medical Research Council.

Buprenorphine for neuropathic pain in adults

BACKGROUND

Opioid drugs, including buprenorphine, are commonly used to treat neuropathic pain, and are considered effective by some professionals. Most reviews have examined all opioids together. This review sought evidence specifically for buprenorphine, at any dose, and by any route of administration. Other opioids are considered in separate reviews.

OBJECTIVES

To assess the analgesic efficacy of buprenorphine for chronic neuropathic pain in adults, and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE from inception to 11 June 2015, together with reference lists of retrieved papers and reviews, and two online study registries.

SELECTION CRITERIA

We included randomised, double-blind studies of two weeks' duration or longer, comparing any oral dose or formulation of buprenorphine with placebo or another active treatment in chronic neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality. We did not carry out any pooled analyses.

MAIN RESULTS

Searches identified 10 published studies, and one study with results in ClinicalTrials.gov. None of these 11 studies satisfied our inclusion criteria, and so we included no studies in the review.

AUTHORS' CONCLUSIONS

There was insufficient evidence to support or refute the suggestion that buprenorphine has any efficacy in any neuropathic pain condition.

Influence of UGT2B7, CYP3A4, and OPRM1 Gene Polymorphisms on Transdermal Buprenorphine Pain Control in Patients with Critical Lower Limb Ischemia Awaiting Revascularization

BACKGROUND

Pain control in critical limb ischemia (CLI) varies considerably between individuals.

OBJECTIVE

To evaluate pharmacogenetically the response to transdermal buprenorphine (BUP-TTS) in patients with CLI who are awaiting revascularization.

METHODS

One hundred and seven patients with CLI were treated with BUP-TTS. The following were analyzed: (1) pain perception (visual analog scale (VAS) before and 4 days after treatment) and (2) genetics: glucuronosyltransferase (UGT2B7), cytochrome (CYP3A4), and μ-opioid receptor (OPRM1) gene polymorphisms.

RESULTS

Ninety-three patients completed the study. The VAS score by the fourth day of analgesia dropped from 6.82 to 3.38 (P < 0.05). The analgesic response to BUP-TTS was greater in men than in women (P = 0.019). Patients who were AA homozygotes for the CYP3A4 gene showed the best response to analgesic treatment (P = 0.003). The combination of the CYP3A4 gene with UGT2B7 or OPRM1 was favorable to the effect of the CYP3A4 gene (P = 0.045 and P = 0.026, respectively). The combination of UGT2B7 with OPRM1 was ineffective (P = 0.648). The 3 polymorphisms together had no effect on response to treatment (P = 0.461).

CONCLUSIONS

BUP-TTS is efficacious in the control of pain in patients with CLI. The homozygous AA carriers of the CYP3A4 gene respond better to treatment with BUP-TTS.

Eight-Year Trends in the Use of Opioids, Other Analgesics, and Psychotropic Medications Among Institutionalized Older People in Finland

IMPORTANCE

It is recognized that pain has been undertreated and psychotropic medications overused in institutional settings.

OBJECTIVE

To investigate the change in prevalence of opioids, other analgesics, and psychotropic medications in institutional settings over an 8-year period.

SETTINGS

Institutional settings in Helsinki, Finland.

PARTICIPANTS

Older residents in nursing homes in 2003 (n = 1987) and 2011 (n = 1576) and in assisted living facilities in 2007 (n = 1377) and 2011 (n = 1586).

OUTCOME MEASURES

Comparable audits of medication use were conducted among institutionalized residents at 3 time points over 8 years. The prevalence of regular opioid, other analgesic, and psychotropic medications was compared across the 3 time periods.

RESULTS

Nursing home and assisted living facility residents were older; more disabled, had a higher prevalence of dementia, and greater comorbidity in the latter cohorts. The prevalence of regular opioid use was 11.8% and 22.9% in nursing homes in 2003 and 2011 (P < .001), and 8.6% and 17.3% in assisted living facilities in 2007 and 2011 (P < .001), respectively. The prevalence of regular acetaminophen and pregabalin/gabapentin increased and NSAIDs decreased in both nursing homes and assisted living facilities. The prevalence of regular antipsychotic use decreased from 42.6% to 27.8% in nursing homes (P < .001) but increased from 26.9% to 32.0% in assisted living facilities (P = .0017). The mean number of psychotropic medications (antipsychotics, antidepressants, anxiolytics, hypnotics) per resident decreased from 1.9 in 2003 to 1.0 in 2011 in nursing homes (P < .001) but increased from 1.1 to 1.2 in assisted living facilities (P = .040).

CONCLUSIONS

The prevalence of opioid use in institutional settings has doubled during the past decade. The prevalence of psychotropic medications has decreased in nursing homes but increased in assisted living facilities. The increase in opioid use may reflect improved recognition and treatment of pain. However, initiatives are needed to monitor opioid-related adverse drug events and ensure appropriate use of psychotropic medications, particularly in assisted living facilities.

The Risk of Opioid Intoxications or Related Events and the Effect of Alcohol-Related Disorders: A Retrospective Cohort Study in German Patients Treated with High-Potency Opioid Analgesics

INTRODUCTION

Intoxications involving prescription opioids are a major public health problem in many countries. When taken with opioids, alcohol can enhance the effects of opioids, particularly in the central nervous system. However, data quantifying the impact of alcohol involvement in opioid-related intoxications are limited.

METHODS

Using claims data from the German Pharmacoepidemiological Research Database (GePaRD), we conducted a retrospective cohort study based on users of high-potency opioid (HPO) analgesics during the years 2005-2009. HPO use was classified as extended-release, immediate-release or both. We calculated incidence rates (IRs) for opioid intoxications or related events as well as adjusted IR ratios (aIRR) comparing HPO-treated patients with alcohol-related disorders (ARDs) to those without ARDs overall and within each HPO category.

RESULTS

During the study period, 308,268 HPO users were identified with an overall IR of 340.4 per 100,000 person-years [95 % confidence interval (CI) 325.5-355.7]. The risk was highest when patients received concomitant treatment with extended- and immediate-release HPOs (IR 1093.8; 95 % CI 904.6-1310.9). ARDs increased the risk during HPO use by a factor of 1.7 and the highest aIRR was seen when comparing patients simultaneously exposed to extended- and immediate-release HPOs with ARDs to those without ARD also after excluding patients with potential improper/non-medical HPO use.

CONCLUSIONS

Physicians should be aware of these elevated risks in HPO patients with ARDs. Active patient education by healthcare providers regarding the risk of opioid intoxications or related events due to alcohol in conjunction with HPOs is warranted.

Noninterventional study of transdermal fentanyl (fentavera) matrix patches in chronic pain patients: analgesic and quality of life effects

Fentanyl is considered to be an effective, transdermal treatment of chronic, cancer, and noncancer pain. This noninterventional, clinical practice-based study, on 426 patients attending 42 practices, assessed a proprietary, Aloe vera-containing, transdermal fentanyl matrix patch (Fentavera), for its analgesic effects, patients' quality of life (QoL) effects, tolerability, and adhesiveness. Study outcomes were mean changes from baseline of patient (11-point scales) and physician (5-point scales) ratings. After 1 and 2 months treatment, there were significant (P < 0.0001) decreases in patients' ratings of pain intensity, and impairment of walking, general activity, sleep quality, and QoL. For each parameter, the patient response rate was >30% at 2 months (response = 2-point decrease on 11-point rating scale). In a large majority of patients, the physicians rated the matrix patch as good or very good for analgesic effect, systemic and local tolerance, and adhesiveness. There were 30 adverse events in 4.2% of patients and analgesic comedications were reduced during treatment compared to before treatment. It is concluded, from this population-based data, that the proprietary, transdermal fentanyl matrix patch is effective and safe for chronic pain management in clinical practice, with significant positive analgesic and QoL effects, while being well tolerated and exhibiting good or very good adhesiveness.

Evaluation of thermal antinociceptive effects after intramuscular administration of buprenorphine hydrochloride to American kestrels (Falco sparverius)

OBJECTIVE

To evaluate the thermal antinociceptive effects and duration of action of buprenorphine hydrochloride after IM administration to American kestrels (Falco sparverius).

ANIMALS

12 healthy 3-year-old American kestrels.

PROCEDURES

Buprenorphine hydrochloride (0.1, 0.3, and 0.6 mg/kg) and a control treatment (saline [0.9% NaCl] solution) were administered IM in a randomized crossover experimental design. Foot withdrawal response to a thermal stimulus was determined 1 hour before (baseline) and 1.5, 3, and 6 hours after treatment administration. Agitation-sedation scores were determined 3 to 5 minutes before each thermal stimulus. Adverse effects were monitored for 6 hours after treatment administration.

RESULTS

Buprenorphine hydrochloride at 0.1, 0.3, and 0.6 mg/kg, IM, increased thermal threshold for 6 hours, compared with the response for the control treatment. There were no significant differences among buprenorphine treatments. A mild sedative effect was detected at a dose of 0.6 mg of buprenorphine/kg.

CONCLUSION AND CLINICAL RELEVANCE

At the doses tested, buprenorphine hydrochloride resulted in thermal antinociception in American kestrels for at least 6 hours, which suggested that buprenorphine has analgesic effects in this species. Further studies with longer evaluation periods and additional forms of noxious stimuli, formulations, dosages, and routes of administration are needed to fully evaluate the analgesic effects of buprenorphine in American kestrels.

Pain in the cancer patient: different pain characteristics CHANGE pharmacological treatment requirements

Twenty years ago, the main barriers to successful cancer pain management were poor assessment by physicians, and patients' reluctance to report pain and take opioids. Those barriers are almost exactly the same today. Cancer pain remains under-treated; in Europe, almost three-quarters of cancer patients experience pain, and almost a quarter of those with moderate to severe pain do not receive any analgesic medication. Yet it has been suggested that pain management could be improved simply by ensuring that every consultation includes the patient's rating of pain, that the physician pays attention to this rating, and a plan is agreed to increase analgesia when it is inadequate. After outlining current concepts of carcinogenesis in some detail, this paper describes different methods of classifying and diagnosing cancer pain and the extent of current under-treatment. Key points are made regarding cancer pain management. Firstly, the pain may be caused by multiple different mechanisms and therapy should reflect those underlying mechanisms - rather than being simply based on pain intensity as recommended by the WHO three-step ladder. Secondly, a multidisciplinary approach is required which combines both pharmacological and non-pharmacological treatment, such as psychotherapy, exercise therapy and electrostimulation. The choice of analgesic agent and its route of administration are considered, along with various interventional procedures and the requirements of palliative care. Special attention is paid to the treatment of breakthrough pain (particularly with fast-acting fentanyl formulations, which have pharmacokinetic profiles that closely match those of breakthrough pain episodes) and chemotherapy-induced neuropathic pain, which affects around one third of patients who receive chemotherapy. Finally, the point is made that medical education should place a greater emphasis on pain therapy, both at undergraduate and postgraduate level.

Buprenorphine for Cancer Pain

Buprenorphine (BUP) is a semisynthetic derivative of the opium alkaloid thebaine found in the poppy Papaver somniferum. Its chemical structure contains the morphine structure but differs by having a cyclopropylmethyl group. Buprenorphine is a potent µ opioid agonist. Buprenorphine undergoes extensive first-pass metabolism in the liver and gut. The development of a transdermal BUP formulation in 2001 led to its evaluation in cancer pain. This article provides the practitioner with an update on the current role of BUP in cancer care. It highlights data suggesting effectiveness in various types of cancer pain. The article reviews pharmacology, routes of administration, adverse effects, drug interactions, and cost considerations.

[Long-term treatment of chronic pain with low-dose 7-day buprenorphine transdermal patch. Observational data from elderly patients of pain relief and quality of life]

BACKGROUND

Six-months analysis of non-interventionally collected observation data of effectiveness of long-term treatment with low-dose 7-day buprenorphine transdermal patch in elderly patients with chronic pain.

METHODS

Analysis of data regarding pain intensity, pain-related impairments of daily life and quality of life documented by 321 pain patients in German primary care (age 72.4 +/- 13.8 years; 67.3% female; musculoskeletal pain 85.4%; mean pain intensity 6.1 +/- 1.2, for 90% > or = 5 NRS11) using standardised self-report instruments (German Pain Questionnaire/German Pain Diary).

RESULTS

After initiation with 5/10 microg/h buprenorphine (89.7%/10.3%), treatment was maintained in 57.1/39.1/3.8% patients with stable doses of 5/10/20 microg/h after 6 months. The average pain intensity decreased by 5.1 +/- 1.0 (absolute) to 1.0 +/- 1.0 NRS11 (83.5%), pain-related impairments and burden of pain were reduced by 86.0% and 87.9%, respectively, and pain-related quality of life improved by 97.3% to nearly normalvalues.

CONCLUSIONS

Pain treatment of elderly persons with 7-day low-dose transdermal buprenorphine patch on a stable dose regimen resulted in fast, effective and sustained pain relief accompanied by marked improvements in daily life participation and quality of life.

Retrospective analysis of 4 years of clinical experience with transdermal buprenorphine (Transtec®) in post-traumatic pain

SUMMARY: 

Aims: To evaluate the effectiveness and safety of transdermal buprenorphine (BTDS) in the treatment of post-traumatic pain in a working population. Patients & methods: Retrospective case series of patients with severe post-traumatic pain treated with BTDS between 2008 and 2012. Results: 57 patients were evaluated: 38 men, 19 women (mean age 43 years); patients with burns (n = 22), skin degloving (14), open dislocations (eight), traumatic nerve lesions (six), spinal cord injury (four) and limb amputations (three). 25, 12 and 20 patients experienced neuropathic pain, nociceptive pain or neuropathic/nociceptive pain, respectively. The mean baseline DN4 questionnaire and pain intensity scores were 4.8±2.3 and 7.4±1.5, respectively. The mean duration of pain before BTDS use was 24.4 months (>3 months in 65% of patients). Total patient-years of BTDS treatment were 73. After 14.7±14.9 months of BTDS treatment, mean pain intensity was reduced by 4.2±2.2 points, 38 patients (66.7%) had ≥50% pain relief, 69% reported functional improvement, especially in gait ability (25) and activities of daily life (14), and 46 patients (80.7%) had improved sleep quality. The starting dose of BTDS was 4.4–17.5 μg/h; maintenance dose was 8.8–70 μg/h. At the start of BTDS treatment, all patients used a total of 187 concomitant analgesics daily, 72% of which were stopped during treatment with BTDS; the number of patients that could be managed exclusively with BTDS and rescue analgesia increased to 31%. 13 patients (22%) presented nausea, eight constipation, six local skin reactions, three vomiting and somnolence, and two patients experienced dizziness. Four patients (6.9%) stopped BTDS due to adverse reactions. Conclusions: BTDS is an effective and safe alternative for the treatment of patients with severe post-traumatic pain, reducing the intensity of pain and improving functional capacity and quality of sleep.

Systematic review of adverse events of buprenorphine patch versus fentanyl patch in patients with chronic moderate-to-severe pain

SUMMARY This systematic review compares convenience of administration, adverse events and tolerability of buprenorphine patch with fentanyl patch in patients with chronic pain. Methods of quantitative and qualitative research were combined. Seventeen databases were searched up to December 2010. A total of 49 unique trials (56 publications) were included. Patients regarded the use of patches, both transdermal buprenorphine and fentanyl, as easy and convenient. Compared with buprenorphine patch, fentanyl can cause more cases of constipation and could lead to a higher number of serious adverse events. There were no differences between buprenorphine patch and fentanyl patch regarding dizziness, somnolence, nausea and treatment discontinuation. Overall, transdermal administration of buprenorphine and fentanyl can be seen as an alternative pathway for delivering these drugs. Use of transdermal buprenorphine might be favorable in certain groups of patients, such as renally impaired, elderly and immunosuppressed patients.

Buprenorphine therapy: an increasing challenge in oral and maxillofacial surgery

Suboxone is a 4:1 mixture of buprenorphine and naloxone and Subutex is buprenorphine alone. The high affinity μ-receptor binding of buprenorphine (Suboxone and Subutex) renders other opioids ineffective. Inadequate procedural sedation, inadequate analgesia, and significant drug interactions complicate the treatment of patients taking Suboxone or Subutex. Careful planning and an understanding of buprenorphine pharmacology can minimize potential perioperative complications in patients taking Suboxone or Subutex.

A successful Switch From Transdermal Fentanyl to Transdermal Buprenorphine in a Patient with Neuropathic Pain

Buprenorphine is a frequently used opioid in the treatment of neuropathic pain component that is often present in patients with cancer. A case of a 41-year-old patient was depicted whose pain syndrome was associated with the chondrosarcoma growth originating from the sacral bone and numerous surgical interventions and radiotherapy. Improvement in analgesia and good toleration of therapy were observed after switching from transdermal fentanyl to transdermal buprenorphine while maintaining treatment with antidepressants and anticonvulsants. This case report indicates a possibility of a safe switch of transdermal opioids at home, which may provide benefits in terms of analgesia and adverse effects and in consequence have positive impact on the patients’ quality of life. This is also accompanied by constant psychological, social, and spiritual support provided to the patient and family.

Treatment retention among patients randomized to buprenorphine/naloxone compared to methadone in a multi-site trial

AIMS

To examine patient and medication characteristics associated with retention and continued illicit opioid use in methadone (MET) versus buprenorphine/naloxone (BUP) treatment for opioid dependence.

DESIGN, SETTINGS AND PARTICIPANTS

This secondary analysis included 1267 opioid-dependent individuals participating in nine opioid treatment programs between 2006 and 2009 and randomized to receive open-label BUP or MET for 24 weeks.

MEASUREMENTS

The analyses included measures of patient characteristics at baseline (demographics; use of alcohol, cigarettes and illicit drugs; self-rated mental and physical health), medication dose and urine drug screens during treatment, and treatment completion and days in treatment during the 24-week trial.

FINDINGS

The treatment completion rate was 74% for MET versus 46% for BUP (P < 0.01); the rate among MET participants increased to 80% when the maximum MET dose reached or exceeded 60 mg/day. With BUP, the completion rate increased linearly with higher doses, reaching 60% with doses of 30-32 mg/day. Of those remaining in treatment, positive opioid urine results were significantly lower [odds ratio (OR) = 0.63, 95% confidence interval (CI) = 0.52-0.76, P < 0.01] among BUP relative to MET participants during the first 9 weeks of treatment. Higher medication dose was related to lower opiate use, more so among BUP patients. A Cox proportional hazards model revealed factors associated with dropout: (i) BUP [versus MET, hazard ratio (HR) = 1.61, CI = 1.20-2.15], (ii) lower medication dose (<16 mg for BUP, <60 mg for MET; HR = 3.09, CI = 2.19-4.37), (iii) the interaction of dose and treatment condition (those with higher BUP dose were 1.04 times more likely to drop out than those with lower MET dose, and (iv) being younger, Hispanic and using heroin or other substances during treatment.

CONCLUSIONS

Provision of methadone appears to be associated with better retention in treatment for opioid dependence than buprenorphine, as does use of provision of higher doses of both medications. Provision of buprenorphine is associated with lower continued use of illicit opioids.

Buprenorphine for chronic pain

Questions from patients about pain conditions, analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. The use of transdermal buprenorphine for chronic pain management is discussed. A brief history of the medication is provided. The use of the medication in opioid maintenance, and withdrawal and other concerns are discussed. Possible side effects are described.

High-sensitivity analysis of buprenorphine, norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide in plasma and urine by liquid chromatography-mass spectrometry

A new method using ultra-fast liquid chromatography and tandem mass spectrometry (UFLC-MS/MS) was developed for the simultaneous determination of buprenorphine and the metabolites norbuprenorphine, buprenorphine-3β-glucuronide, and norbuprenorphine-3β-glucuronide in plasma and urine. Sample handling, sample preparation and solid-phase extraction procedures were optimized for maximum analyte recovery. All four analytes of interest were quantified by positive ion electrospray ionization tandem mass spectrometry after solid-phase microextraction. The lower limits of quantification in plasma were 1pg/mL for buprenorphine and buprenorphine glucuronide, and 10pg/mL for norbuprenorphine and norbuprenorphine glucuronide. The lower limits of quantitation in urine were 10pg/mL for buprenorphine, norbuprenorphine and their glucuronides. Overall extraction recoveries ranged from 68-100% in both matrices. Interassay precision and accuracy was within 10% for all four analytes in plasma and within 15% in urine. The method was applicable to pharmacokinetic studies of low-dose buprenorphine.

A feasibility study of transdermal buprenorphine versus transdermal fentanyl in the long-term management of persistent non-cancer pain

OBJECTIVE

Buprenorphine and fentanyl transdermal patches are used widely for the management of persistent malignant and nonmalignant pain. Buprenorphine and fentanyl transdermal patches, both potent opioids, are considered to be equally efficacious in managing persistent pain. Various retrospective studies comparing dosage changes of buprenorphine and fentanyl patches in persistent pain patients have been completed; however, no long-term prospective, randomized, clinical study has compared the effectiveness of these patches. The objective of the present study was to satisfy this need.

AIMS

This study aims to compare prospectively the long-term efficacy, acceptability, and side effects of both of these patches in patients with persistent pain. This study would examine the feasibility and lay the groundwork for a larger, multicenter study where such efficacy and safety outcomes of the two medications can be adequately assessed.

DESIGN

The participants were 46 adults (range 22-80 years.) with nonmalignant persistent pain (mean = 11 years), predominantly with lower back pain. Data were obtained monthly for 12 months. Participants recruited were opioid-naïve patients, having pain for the greater part of the day and night, and appropriate for treatment with transdermal patches. After initial assessment, participants were randomly allocated to either buprenorphine or fentanyl patch treatment. Participants were then titrated to optimal doses of medication. Patients with adverse effects or unsatisfactory pain relief were treated alternatively and discontinued from the study.

RESULTS

Nearly one-third of all patients, 41% (8 of 22) of the transdermal buprenorphine (TDB) group and 37.5% (8 of 24) of the transdermal fentanyl (TDF) group stopped treatment due to unacceptable side effects or inadequate pain relief. The remaining participants showed a similar trend in the improvement of pain intensity, physical activity, sleep, and mood throughout the study. Significant relief in the intensity of pain was achieved for the initial 6 months and the effects stabilized in the remainder of the study in both groups. There were no significant group differences over time. However, a higher equipotent dose of fentanyl was required for comparable pain relief. Compared with TDF group, the TDB group initially experienced relatively less side effects. However, a greater number of buprenorphine users suffered from local skin reactions. Buprenorphine users had significant improvement in mood. Thirty-one percent (5 of 16) of the buprenorphine group and 57% (8 of 14) of the fentanyl users needed additional pain relief medications by the end of 3 months. By the end of 12 months, a significant number 78% (7 of 9) of buprenorphine users but comparatively fewer 44% (4 of 9) of the fentanyl group used rescue medicines. Both had more doctor visits in the latter half of the study.

CONCLUSION

Thirty percent of the total number of patients discontinued treatment because of side effects or unsatisfactory pain relief. For those continuing treatment, clinical improvements were seen in the initial 6 months in both groups. Fifty percent of the TDB and 43% of TDF groups had significant relief in 3 months, which persisted up to 6 months. Only 11% and 13% of patients, respectively, had sustained relief after 6 months. Twenty percent more patients in the TDB group benefited significantly in symptoms of depression from TDB compared with the TDF group. Interestingly, switching of patches seemed to increase acceptability by preventing adverse effects and tolerance. Confirmation of these effects should be studied in future with a multicenter study and larger sample.

Buprenorphine—Clinically useful but often misunderstood

Background

There are a number of false myths about buprenorphine based on unconfirmed animal data, even from isolated animal organs, and early clinical research. These myths came into textbooks on pharmacology and pain about 30 years ago and have been difficult to eradicate. Animal models of pain and pain relief are notoriously unreliable as predictors of human clinical effects. The fact is that in clinical practice there is NO bell-shaped dose-response curve, there is NO plateau on the dose-response curve, and there is NO antagonist effect from buprenorphine on other mu-opioid agonists.

Methods

This narrative, topical review of relevant research publications evaluates new knowledge on the pharmacodynamics and pharmacokinetics of buprenorphine of importance in clinical practice.

Results

Buprenorphine is a potent opioid analgesic acting on all four opioid receptors: it is an agonist on the mu-, the delta, and the ORL-1 receptors. It is an antagonist at the kappa-receptor. Buprenorphine has a number of active metabolites with different effects on the four opioid receptors; all except the norbup-3-glu are analgesic. Buprenorphine itself is not a respiratory depressant or sedative, but some of its active metabolites are. Buprenorphine and its active metabolites are not excreted by the kidney. Therefore buprenorphine may be used in patients with advanced renal failure.

Buprenorphine has a slow onset and a long offset. These properties are advantageous, except sometimes when treating severe acute pain. Its agonist effect on the ORL-1 receptor reduces reward-effects and slows the development of tolerance to the analgesic effects.

Buprenorphine inhibits voltage-gated sodium-channels and enhances and prolongs peripheral nerve blocks. Its ORL-1 -effect at the spinal cord may do the same.

Buprenorphine is well suited for treatment of chronic pain, especially chronic neuropathic pain and cancer pain. The beneficial effects as a co-medication during treatment of the opioid-abuse disease are due to its slow onset (less “kick-effect”). Its prolonged offset-time reduces the likelihood of acute withdrawal problems and reduces the “craving” of opioids.

Adverse effects

Buprenorphine, being a mu-agonist, may induce or maintain opioid addiction. Illegally obtained high-dose transmucosal buprenorphine, intended for treatment of addiction, is dissolved and injected by opioid abusers. This is an increasing problem in some countries.

Conclusions

Buprenorphine’s unusual pharmacodynamics and pharmacokinetics make it an ideal opioid for treatment of most chronic pain conditions where opioid therapy is indicated.

Implications

Buprenorphine is a well studied and often misunderstood analgesic opioid drug. The evidence base predicts that it will be an increasingly important alternative for treatment of chronic pain conditions caused by cancer and non-cancer diseases. It will continue to be an attractive alternative to methadone for opioid abuse rehabilitation.

Once-weekly transdermal buprenorphine application results in sustained and consistent steady-state plasma levels

CONTEXT

Transdermal formulations of buprenorphine offer controlled delivery of buprenorphine for sustained analgesic efficacy with reduced adverse events (AEs) compared with the other modes of administration. A buprenorphine transdermal system (BTDS) delivering 5, 10, or 20 mcg/hour for seven days is now marketed in the U.S. as Butrans(®) (Lohmann Therapie-System AG, Andernach Germany), a Schedule III single-entity opioid analgesic indicated for the management of moderate and chronic pain in patients requiring continuous around-the-clock analgesia for an extended period.

OBJECTIVES

This was a randomized open-label study in healthy subjects to characterize the steady-state buprenorphine pharmacokinetics after the delivery of three consecutive seven-day BTDS applications.

METHODS

Thirty-seven subjects were randomized to receive three consecutive BTDS 10 mcg/hour (BTDS 10) patches applied to the deltoid or upper back for seven days each. Blood samples for buprenorphine concentration measurements were taken. Safety was assessed using recorded AEs, clinical laboratory test results, vital signs, pulse oximetry, physical examinations, and electrocardiograms. Patch adhesion assessments were taken.

RESULTS

Analysis of Cmin demonstrated that steady state was reached during the first BTDS 10 application. No significant difference in Cmin was observed across the three applications. Total and peak plasma buprenorphine exposures were similar after each of the seven-day administrations of BTDS.

CONCLUSION

Three consecutive once-weekly applications of BTDS 10 provided consistent and sustained delivery of buprenorphine. Steady-state plasma concentrations were reached within 48 hours of the first application of BTDS 10. Patch adhesion analysis confirmed the appropriateness of the seven-day application period. Overall, BTDS 10 was safe and well tolerated.

Effects of spinally administered bifunctional nociceptin/orphanin FQ peptide receptor/μ-opioid receptor ligands in mouse models of neuropathic and inflammatory pain

Nociceptin/orphanin FQ peptide receptor (NOP) agonists produce antinociceptive effects in animal models after spinal administration and potentiate μ-opioid receptor (MOP)-mediated antinociception. This study determined the antinociceptive effects of spinally administered bifunctional NOP/MOP ligands and the antinociceptive functions of spinal NOP and MOP receptors in mice. Antinociceptive effects of bifunctional NOP/MOP ligands BU08028 [(2S)-2-[(5R,6R,7R,14S)-N-cyclopropylmethyl-4,5-epoxy-6,14-ethano-3-hydroxy-6-methoxymorphinan-7-yl]-3,3-dimethylpentan-2-ol] and SR16435 [1-(1-(2,3,3α,4,5,6-hexahydro-1H-phenalen-1-yl)piperidin-4-yl)-indolin-2-one] were pharmacologically compared with the putative bifunctional ligand buprenorphine, selective NOP agonist SCH221510 [3-endo-8-[bis(2-methylphenyl)methyl]-3-phenyl-8-azabicyclo[3.2.1]octan-3-ol] and selective MOP agonist morphine in neuropathic and inflammatory pain models. Additionally, the degree of tolerance development to the antiallodynic effects of SR16435 and buprenorphine were determined after repeated intrathecal administration. Our data indicated that BU08028 and SR16435 were more potent than morphine and SCH221510 in attenuating nerve injury-induced tactile allodynia and inflammation-induced thermal hyperalgesia. Coadministration of receptor-selective antagonists further revealed that both NOP and MOP in the spinal cord mediated the antiallodynic effects of BU08028 and SR16435, but intrathecal buprenorphine-induced antiallodynic effects were primarily mediated by MOP. Repeated intrathecal administration of SR16435 resulted in reduced and slower development of tolerance to its antiallodynic effects compared with buprenorphine. In conclusion, both NOP and MOP receptors in the spinal cord independently drive antinociception in mice. Spinally administered bifunctional NOP/MOP ligands not only can effectively attenuate neuropathic and inflammatory pain, but also have higher antinociceptive potency with reduced tolerance development to analgesia. Such ligands therefore display a promising profile as spinal analgesics.

The use of high dosages of transdermal buprenorphine for pain management in palliative cancer patients: a case study

Pain is a prevalent condition in patients with cancer, particularly in advanced stages of cancer. Although strong opioids are the mainstay of cancer pain management protocols, patients are often undertreated. Transdermal buprenorphine is currently available for the treatment of moderate to severe cancer pain and severe pain which does not respond to nonopioid analgesics; patch doses of 35, 52.5 and 70 µg/h are available (applied for up to 96 h), with no more than 2 transdermal patches at the same time, regardless of the strength. To date, there are no published reports in the literature of the use of high-dose transdermal buprenorphine (>140 µg/h). Herein, we present 2 cases of palliative cancer patients who received transdermal buprenorphine at doses titrated up to 210 and 175 µg/h, respectively, for the management of pain. Transdermal buprenorphine titrated to doses >140 µg/h provided adequate pain control and was well tolerated. Future studies to confirm these initial observations are warranted.