Patterns of Dosage changes with transdermal buprenorphine and transdermal fentanyl for the treatment of noncancer and cancer pain: A retrospective data analysis in Germany

Buprenorphine: an old dog with new tricks

PURPOSE OF REVIEW

The survival rate of patients with a cancer or palliative care diagnosis has improved over the years although pain remains a debilitating symptom that many patients still require treatment with opioids. Compared to full mu-opioid receptor agonists such as morphine and oxycodone, buprenorphine continues to remain a second- or third-line choice in this group of patients.We have reviewed the pharmacology and clinical utility of buprenorphine to stimulate debate around the first-line use of buprenorphine in the management of pain in cancer patients.

RECENT FINDINGS

Buprenorphine has a pharmacological profile that is unique and unlike any other opioid. It is associated with many immediate and long-term benefits, with lower risks of adverse effects that make it an ideal first-line choice in the management of cancer pain.

SUMMARY

Buprenorphine appears to be a promising choice of opioid for cancer patients. Studies have found that buprenorphine is a safe and effective choice for many patients, making it a suitable first-line option for the management of cancer pain.

Repeated High-dose Fentanyl Administration in Rats Reveals Minimal Tolerance to Unconsciousness, Bradycardia, Muscle Rigidity, and Respiratory Depression

BACKGROUND

Fentanyl is a synthetic opioid that is widely used in anesthesiology, but its illicit use is rapidly increasing. At high doses, fentanyl induces unconsciousness and muscle rigidity, the mechanisms of which are poorly understood. Since animal models are needed to study these effects, the aim of this study was to establish a rat model of fentanyl abuse and investigate the effects of repeated high-dose fentanyl injections on loss of righting reflex, heart rate, respiratory depression, muscle, and brain activity.

METHODS

Male and female Sprague-Dawley rats were studied (n = 40). A bolus of 100 µg/kg fentanyl was administered intravenously twice a week for 5 consecutive weeks. Time to return of righting reflex after fentanyl injection and changes in electromyography/electroencephalography activity as well as heart rate were analyzed. Additionally, arterial blood gas analysis for evaluation of ventilation was performed. Mixed-effect models with Dunnett test and effect sizes were used for statistical analysis.

RESULTS

Repeated injections resulted in a U-shaped change in time to return of righting reflex with the longest latency after the first exposure (median, 50 [first to third quartile, 36 to 56] min) and the shortest after the fifth exposure (16 [13 to 33] min). After fentanyl administration, heart rate dropped immediately by 225 beats/min (95% CI, 179 to 271; F = 3,952.16; P < 0.001), while electromyography activity increased by 291% (95% CI, 212 to 370; F = 27.51; P < 0.001) and partial pressure of arterial carbon dioxide increased by 49.4 mmHg (95% CI, 40.6 to 58.2; F = 75.97; P < 0.001) within 5 min after injection. Additionally, pH decreased by 0.48 (95% CI, 0.41 to 0.54; F = 142.00; P < 0.01), and partial pressure of arterial oxygen decreased by 50.4 mmHg (40.8 to 60.0; F = 57.90; P < 0.001). Repeated fentanyl exposures did not significantly affect the extent of these changes (EMG, F = 1.63, P = 0.237; partial pressure of arterial carbon dioxide, F = 1.23, P = 0.312; heart rate, F = 1.05, P = 0.400; pH, F = 3.05, P = 0.066; arterial partial pressure of oxygen, F = 3.35, P = 0.052). Electroencephalography analysis revealed that repeated fentanyl exposures elicited significantly higher absolute power in frequencies greater than 20 Hz as indicated by an area under the receiver operator characteristics curve greater than 0.7.

CONCLUSIONS

The authors established a rodent model of repeated high-dose fentanyl administration. Overall, significant evidence of tolerance was not observed after 10 exposures of high-dose fentanyl for any of the analyzed parameters. These results suggest that tolerance does not develop for fentanyl-induced unconsciousness, muscle rigidity, or respiratory depression.

Buprenorphine for Chronic Pain Management: a Narrative Review

PURPOSE OF REVIEW

The aim of this review is to educate healthcare professionals regarding buprenorphine for the use of opioid use disorder (OUD) as well as for chronic pain management. This review provides physicians and practitioners with updated information regarding the distinct characteristics and intricacies of prescribing buprenorphine.

RECENT FINDINGS

Buprenorphine is approved by the US Food and Drug Administration (FDA) for acute pain, chronic pain, opioid use disorder (OUD), and opioid dependence. When compared to most other opioids, buprenorphine offers superior patient tolerability, an excellent half-life, and minimal respiratory depression. Buprenorphine does have notable side effects as well as pharmacokinetic properties that require special attention, especially if patients require future surgical interventions. Many physicians are not trained to initiate or manage patients on buprenorphine. However, buprenorphine offers a potentially safer alternative for medication management for patients who require chronic opioid therapy for pain or have OUD. This review provides updated information on buprenorphine for both chronic pain and OUD.

Safety and effectiveness of transdermal buprenorphine in cancer pain: An observational study in Taiwan (SOOTHE)

AIM

Buprenorphine is one of the strongest opioids used for the relief of cancer pain. This study aims to evaluate the real-world clinical experiences of transdermal buprenorphine used in moderate to severe cancer pain in the Asian population.

METHODS

This is an open-labeled, multicenter, 4-week observational study. Stable cancer pain patients who decided to switch the previous opioid to transdermal buprenorphine will be enrolled in this study. The safety and effectiveness were observed and collected. Pain assessment was performed using a numerical rating scale by the investigators and the Brief Pain Inventory Short Form (BPI-SF) by the patient. The safety profiles included concomitant medications and adverse events (AEs).

RESULTS

A total of 83 patients were enrolled in this study. The global pain scores in the BPI, as well as the four individual pain parameters (worst, least, average, and right now), showed a continued decrease (p < .05) from week 2 to week 4. Significant improvements were observed in normal work activities, relations with other people, sleep, enjoyment of life, and global BPI pain interference score on week 4. Pain assessments conducted by investigators demonstrated significant, continuous improvements during the study periods. In addition, transdermal buprenorphine demonstrated good safety/tolerability with limited drug-related AEs in the Asian population with cancer pain.

CONCLUSION

This study demonstrated that transdermal buprenorphine in the Asian population has good safety profiles and continued improvements in pain relief, sleep, and pain interferences. Transdermal buprenorphine can be an effective and convenient option as a transdermal opioid for patients with moderate to severe cancer pain in Taiwan. (NCT Number: NCT04315831).

Treating Chronic Pain: An Overview of Clinical Studies Centered on the Buprenorphine Option

The buprenorphine receptor binding profile is unique in that it binds to all three major opioid receptors (mu, kappa, delta), and also binds to the orphan-like receptor, the receptor for orphanin FQ/nociceptin, with lower affinity. Within the mu receptor group, buprenorphine analgesia in rodents is dependent on the recently discovered arylepoxamide receptor target in brain, which involves a truncated 6-transmembrane mu receptor gene protein, distinguishing itself from morphine and most other mu opioids. Although originally designed as an analgesic, buprenorphine has mainly been used for opioid maintenance therapy and only now is increasingly recognized as an effective analgesic with an improved therapeutic index relative to certain potent opioids. Albeit a second-, third-, or fourth-line analgesic, buprenorphine is a reasonable choice in certain clinical situations. Transdermal patches and buccal film formulations are now commercially available as analgesics. This review discusses buprenorphine pharmacodynamics and pharmacokinetics, use in certain populations, and provides a synopsis of systematic reviews and randomized analgesic trials. We briefly discuss postoperative management in patients receiving buprenorphine maintenance therapy, opioid equivalence to buprenorphine, rotations to buprenorphine from other opioids, and clinical relevance of buprenorphine-related QTc interval changes.

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.

The switch from buprenorphine to tapentadol: is it worth?

Opioid analgesia continues to be the primary pharmacologic intervention for managing acute pain and malignant pain in both hospitalized and ambulatory patients. The increasing use of opioids in chronic nonmalignant pain is more problematic. Opioid treatment is complicated with the risks raised by adverse effects, especially cognitive disturbance, respiratory depression but also the risk of tolerance, opioid abuse and drug-disease interactions. Despite the growing number of available opioids within the last years, adequate trials of opioid rotation are lacking and most of the information is anecdotal. This article reviews the clinical evidence surrounding the switch from transdermal buprenorphine to tapentadol in malignant and non-malignant pain. Tapentadol acts on both the μ-opioid receptors (MOR) and on the neuronal reuptake of noradrenaline with a limited usefulness in acute pain management while buprenorphine is a mixed agonist-antagonist, and both present some advantages over other opioids. Both drugs show particular pharmacodynamic and pharmacokinetic properties which reduce the risks of development of tolerance, opioid abuse, diversion and determine fewer hormone changes than the "classical opioids" making these opioids more attractive than other opioids in long term opioid treatment. However, in the absence of powered clinical trials, the evidence to support the method used for transdermal buprenorphine rotation to tapentadol is weak.

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.

Advanced cancer pain: the search for genetic factors correlated with interindividual variability in opioid requirement

AIM

To assess association between genetic variants and opioid requirement in cancer patients.

MATERIALS & METHODS

A prospective observational trial of 243 advanced cancer patients with inadequate analgesia treated by the palliative care team was analyzed for ABCB1, ARRB2, COMT, GCH1, IL1RN, KCNJ6, OPRM1, RHBDF2, SCN9A and Stat6 polymorphisms.

RESULTS

For patients carrying OPRM1 118AG/GG and COMT 472GG (Val158Val) or these genotypes alone, a significant higher median percentage dose increase was observed (95.2% [32.8-345]) compared with OPRM1 118AA and COMT 472GA/AA (158Met allele carriers; 48.5% [0-98.8]; p = 0.0016). No associations were found with morphine equivalent dose after consultation palliative care team or ketamine use.

CONCLUSION

Patients with the combined OPRM1 118AG/GG and COMT 472GG genotype required 50% higher dose increase for sufficient analgesia.

[Pharmacological aspects of pain research in Germany]

In spite of several approved analgesics, the therapy of pain still constitutes a challenge due to the fact that the drugs do not exert sufficient efficacy or are associated with severe side effects. Therefore, the development of new and improved painkillers is still of great importance. A number of highly qualified scientists in Germany are investigating signal transduction pathways in pain, effectivity of new drugs and the so far incompletely investigated mechanisms of well-known analgesics in preclinical and clinical studies. The highlights of pharmacological pain research in Germany are summarized in this article.

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.

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.

[Pain therapy in the elderly:7-day transdermal buprenorphine patch in clinical practice. Results of a non-interventional study]

BACKGROUND

Chronic pain in the elderly is common. Especially in the elderly inadequate treatment of pain can cause significant functional impairmentand deterioration of qualityof life.

METHODS

Theaim of this post-marketing surveillance study was to collect data from clinical practice on the analgesic efficacy and safety of the 7-day transdermal buprenorphine patch in patients with chronic non-malignant pain pre-treated with opioids. A total of 2713 elderly multimorbid patients were switched to 7-day transdermal buprenorphine patch from previous opioid treatment mainly due to inadequate analgesia. 83% of patients received a 7-day transdermal buprenorphine patch dosage > or = 10 microg/h. During the 8-weekobservation period, data on pain intensity, quality of sleep/life (NRS-11 point scales) and safety wererecorded.

RESULTS

Mean pain intensity decreased by 4 points with 7-day transdermal buprenorphine patch (p < or = 0.001). Quality of sleep and life as well as social activities and self-reliance improved significantly. Compliance and tolerability were assessed as very good/good in > 90% of patients. Adverse drug reactions (ADRs) occurred in 3% of patients and corresponded to 90.1% to the already-known spectrum of ADRs of 7-daytransdermal buprenorphinepatch.

CONCLUSIONS

The results confirm that elderly patients with opioid pre-treatment benefit from a switch to 7-day transdermal buprenorphine patch with regard to reduction of pain and improved quality of life.

Low-dose 7-day transdermal buprenorphine in daily clinical practice - perceptions of elderly patients with moderate non-malignant chronic pain

OBJECTIVE

To assess patients' perceptions regarding the low-dose 7-day buprenorphine transdermal patch for treatment of moderate non-malignant chronic pain.

METHODS

Patient-reported outcome data were collected in clinical practices in Germany in a prospective, multicenter, non-interventional observation using the German Pain Questionnaire/German Pain Diary. Questionnaires were completed by the patients without influence from the attending physician. Mean change in pain intensity (lowest, average, and highest pain intensity in the previous 24 h), changes in Hospital Anxiety and Depression Scale scores (HADS-A and HADS-D), in impairments of daily activities (modified pain disability index, mPDI), in quality of life (quality of life impairment by pain inventory, QLIP), and in overall burden of pain over a 12-week treatment period were evaluated.

RESULTS

Data of 891 patients were assessed (mean age 72.8 years). Buprenorphine starting doses were mainly 5 µg/h (67.1% of patients) and 10 µg/h (27.3%). At the end of week 12, the majority received either 5 µg/h (41%) or 10 µg/h (42.3%) buprenorphine. Mean average pain intensity was reduced by 5.1 points to 1.7 ± 1.3 from 6.8 ± 1.5 points at baseline (76% improvement). Amelioration was observed in HADS-A (59% from 7.8 ± 3.3 at baseline) and HADS-D (56% from 9.2 ± 3.1), in mPDI sum score (76%; from 31.1 ± 9.8), and in quality of life (165%; from 13.9 ± 10.1). Mean burden of pain continuously decreased.

LIMITATIONS

All those inherent in open-label observations and pain studies using subjective and patient-reported outcome parameters (such as the lack of a control group).

CONCLUSIONS

Our results indicate that the 7-day buprenorphine patch might be considered an effective treatment option for moderate non-malignant chronic pain management in daily clinical practice. The mostly elderly patient population of this patient survey experienced sustained pain relief and improvements in pain-related impairments of daily activities and quality of life, leading to a substantial reduction in overall burden of pain.

Mechanisms of rapid opioid receptor desensitization, resensitization and tolerance in brain neurons

Agonists acting on µ-opioid receptors (MOR) are very effective analgesics but cause tolerance during long-term or repeated exposure. Intensive efforts have been made to find novel opioid agonists that are efficacious analgesics but can elude the signalling events that cause tolerance. µ-Opioid agonists differentially couple to downstream signalling mechanisms. Some agonists, such as enkephalins, D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO), methadone and sufentanyl are efficacious at mediating G-protein and effector coupling, as well as triggering MOR regulatory events that include MOR phosphorylation, β-arrestin binding, receptor endocytosis and recycling. By contrast, morphine and closely related alkaloids can mediate efficacious MOR-effector coupling but poorly trigger receptor regulation. Several models have been proposed to relate differential MOR regulation by different opioids with their propensity to cause tolerance. Most are based on dogma that β-arrestin-2 (βarr-2) binding causes MOR desensitization and/or that MOR endocytosis and recycling are required for receptor resensitization. This review will examine some of these notions in light of recent evidence establishing that MOR dephosphorylation and resensitization do not require endocytosis. Recent evidence from opioid-treated animals also suggests that impaired MOR-effector coupling is driven, at least in part, by enhanced desensitization, as well as impaired resensitization that appears to be βarr-2 dependent. Better understanding of how chronic exposure to opioids alters receptor regulatory mechanisms may facilitate the development of effective analgesics that produce limited tolerance.

Analysis of opioid efficacy, tolerance, addiction and dependence from cell culture to human

Opioid agonists are the most effective treatment for pain, but their use is limited by side effects, tolerance and fears of addiction and dependence. A major goal of opioid research is to develop agonists that have high analgesic efficacy and a low profile for side effects, tolerance, addiction and dependence. Unfortunately, there is a serious lack of experimental data comparing the degree to which different opioids produce these effects in humans. In contrast, a wide range of experimental techniques from heterologous expression systems to behaviour assessment in whole animals have been developed to study these problems. The objective of this review is to describe and evaluate these techniques as they are used to study opioid efficacy, tolerance, addiction and dependence.

Combination therapy with transdermal buprenorphine and pregabalin for chronic low back pain

SUMMARY 

AIM

The aim of this study was to evaluate the efficacy and safety of combined transdermal buprenorphine and pregabalin in chronic low back pain.

PATIENTS & METHODS

A total of 45 patients with chronic low back pain were recruited into the study. For an initial 3-week period, all patients received transdermal buprenorphine 35 µg/h. After 3 weeks of only transdermal buprenorphine 35 µg/h, patients were randomized (single-blind) to receive transdermal buprenorphine 35 µg/h plus pregabalin 300 mg/day (group A) or transdermal buprenorphine 35 µg/h plus placebo (group B), and were observed for a further 3-week period. Efficacy parameters were weekly mean Visual Analog Scale (VAS) scores, the Pain Rating Index (PRI) of the Short-Form McGill Pain Questionnaire (SF-MPQ), the Present Pain Index (PPI) of the SF-MPQ and sleep interference. We also evaluated the use of rescue medication (paracetamol [acetaminophen]) and the presence of adverse events.

RESULTS

A total of 44 patients were evaluated for efficacy and safety parameters. Pain relief, as assessed by VAS, PPI and PRI, improved significantly (p < 0.05) in all patients after the first week of treatment with only transdermal buprenorphine. Following randomization, only patients in group A showed further reductions in the mean VAS, PPI and PRI scores. Moreover, patients in group A had a lower consumption of rescue medication than those in group B. There was a low incidence of mild adverse events in both group A and group B, with no serious adverse events in either group.

CONCLUSION

Pregabalin 300 mg/day as an add-on to transdermal buprenorphine 35 µg/h led to significant pain reduction and a significant reduction of interference with sleep quality in patients with chronic low back pain.

Transdermal buprenorphine for the treatment of moderate to severe chronic pain: results from a large multicenter, non-interventional post-marketing study in Poland

OBJECTIVE

To evaluate the use of a buprenorphine transdermal patch (Transtec*) in routine clinical practice, including dosage, indications, efficacy and tolerability.

RESEARCH DESIGN AND METHODS

This prospective, open-label, non-comparative, non-interventional, post-marketing study was performed in Poland by 339 investigators in a range of clinical practice settings. Patients with chronic moderate to severe cancer pain, or chronic severe non-cancer pain that was insufficiently controlled by non-opioids, were prescribed buprenorphine transdermal patch 35, 52.5 or 70 μg/hour (changed twice weekly), and followed up for 3 months. Additional analgesia, and adjuvant/supportive treatments were allowed at the discretion of the physician.

MAIN OUTCOME MEASURES

The study enrolled 4030 patients, with a mean age of 62.8 years. Most patients had cancer-related pain (80.7%). Non-cancer pain was generally musculoskeletal or neuropathic. A starting dose of 35, 52.5 or 70 μg/hour was used in 73.4%, 21.5%, and 4.8% of patients, respectively. Buprenorphine dose was increased in 44.7% of patients during the observation, generally from 35 to 52.5 μg/hour. Mean pain intensity (using a 100 mm visual analogue scale) decreased by 73.5% from 62.3 mm at baseline to 16.5 mm after 3 months. Most patients rated pain relief as 'very good' (41.4%) or 'good' (44.5%). Sleep quality also improved. 48.1% of patients needed no additional analgesics during buprenorphine treatment. Most patients (96%) rated the buprenorphine transdermal patch as 'very easy' or 'easy' to change. The most common treatment-related reasons for discontinuation were lack of analgesic effect (3.3% of patients) and adverse drug reactions (ADRs, 0.8%). ADRs, all non-serious, occurred in 34 patients (0.8%), most commonly local skin reactions or vomiting. At study end, it was planned to continue treatment with transdermal buprenorphine in 70.1% of patients. The main limitations related to the observational study design, balanced by advantages gained from the 'real life' exploration of transdermal buprenorphine use.

CONCLUSIONS

In routine Polish clinical practice, transdermal buprenorphine was effective and generally well-tolerated in patients with chronic moderate to severe cancer pain or chronic severe non-malignant pain insufficiently controlled by non-opioids.

Transdermal buprenorphine - a critical appraisal of its role in pain management

This paper reviews the current clinical data for the role of transdermal buprenorphine (BUP TDS) in the treatment of diverse acute and chronic pain syndromes. Literature searches were carried out using PubMed (1988 to June 2009). The published findings seem to support hypotheses regarding the rather unique analgesic mechanisms of buprenorphine as compared with pure μ-opioids like morphine and fentanyl. However, the exact mechanism of this analgesic efficacy still remains largely unknown despite recent advances in preclinical pharmacological studies. Such assessments have demonstrated the sustained antihyperalgesic effect of buprenorphine in diverse animal pain models. These findings are supported in a growing number of clinical studies of oral, intrathecal, intravenous, and Bup TDS. This review paper focuses almost entirely on the clinical experience concerning the transdermal administration of buprenorphine, although preclinical aspects are also addressed in order to provide a complete picture of the unique pharmacological properties of this analgesic drug. Mounting evidence indicates the appropriateness of Bup TDS in the treatment of diverse acute and chronic pain syndromes which have been less or not responsive to other opioids. Additionally, BUP TDS seems to hold great promise for other difficult-to-treat (pain) conditions, such as patients in the intensive care setting. However, its use is somewhat tempered by the occurrence of local skin reactions which have been shown to be often therapy resistant. Further studies are certainly warranted to identify even more precisely the clinical syndromes that are most sensitive to buprenorphine treatment, and to compare buprenorphine to other opioids in head-to-head trials of acute and chronic pain conditions.

Fentanyl inhibits glucose-stimulated insulin release from β-cells in rat pancreatic islets

AIM: To explore the effects of fentanyl on insulin release from freshly isolated rat pancreatic islets in static culture.

METHODS: Islets were isolated from the pancreas of mature Sprague Dawley rats by common bile duct intraductal collagenase V digestion and were purified by discontinuous Ficoll density gradient centrifugation. The islets were divided into four groups according to the fentanyl concentration: control group (0 ng/mL), group I (0.3 ng/mL), group II (3.0 ng/mL), and group III (30 ng/mL). In each group, the islets were co-cultured for 48 h with drugs under static conditions with fentanyl alone, fentanyl + 0.1 μg/mL naloxone or fentanyl + 1.0 μg/mL naloxone. Cell viability was assessed by the MTT assay. Insulin release in response to low and high concentrations (2.8 mmol/L and 16.7 mmol/L, respectively) of glucose was investigated and electron microscopy morphological assessment was performed.

RESULTS: Low- and high-glucose-stimulated insulin release in the control group was significantly higher than in groups II and III (62.33 ± 9.67 μIU vs 47.75 ± 8.47 μIU, 39.67 ± 6.18 μIU and 125.5 ± 22.04 μIU vs 96.17 ± 14.17 μIU, 75.17 ± 13.57 μIU, respectively, P < 0.01) and was lowest in group III (P < 0.01). After adding 1 μg/mL naloxone, insulin release in groups II and III was not different from the control group. Electron microscopy studies showed that the islets were damaged by 30 ng/mL fentanyl.

CONCLUSION: Fentanyl inhibited glucose-stimulated insulin release from rat islets, which could be prevented by naloxone. Higher concentrations of fentanyl significantly damaged β-cells of rat islets.

Management of chronic pain in the elderly: focus on transdermal buprenorphine

Chronic pain in the elderly is a significant problem. Pharmacokinetic and metabolic changes associated with increased age makes the elderly vulnerable to side effects and overdosing associated with analgesic agents. Therefore the management of chronic cancer pain and chronic nonmalignant pain in this growing population is an ongoing challenge. New routes of administration have opened up new treatment options to meet this challenge. The transdermal buprenorphine matrix allows for slow release of buprenorphine and damage does not produce dose dumping. In addition the long-acting analgesic property and relative safety profile makes it a suitable choice for the treatment of chronic pain in the elderly. Its safe use in the presence of renal failure makes it an attractive choice for older individuals. Recent scientific studies have shown no evidence of a ceiling dose of analgesia in man but only a ceiling effect for respiratory depression, increasing its safety profile. It appears that transdermal buprenorphine can be used in clinical practice safely and efficaciously for treating chronic pain in the elderly.

Cancer pain and analgesia

Pain ranges in prevalence from 14-100% among cancer patients and occurs in 50-70% of those in active treatment. Cancer pain may result from direct invasion of tumor into nerves, bones, soft tissue, ligaments, and fascia, and may induce visceral pain through distension and obstruction. Cancer pain is multifaceted. Clinicians may describe cancer pain as acute, chronic, nociceptive (somatic), visceral, or neuropathic. Despite implementation of the WHO guidelines, reports of undertreatment of cancer pain persist in various clinical settings and in spite of decades of work to reduce unnecessary discomfort. Substantial obstacles to adequate pain relief with opioids include specific concerns of patients themselves, their family members, physicians, nurses, and the healthcare system. The WHO analgesic ladder serves as the mainstay of treatment for the relief of cancer pain in concert with tumoricidal, surgical, interventional, radiotherapeutic, psychological, and rehabilitative modalities. This multidimensional approach offers the greatest potential for maximizing analgesia and minimizing adverse effects. Primary therapies are directed at the source of the cancer pain and may enhance a patient's function, longevity, and comfort. Adjuvant therapies include nonopioids that confer analgesic effects in certain medical conditions but primarily treat conditions that do not involve pain. Nonopioid medications (over-the-counter agents) are useful in the management of mild to moderate pain, and their continuation through step 3 of the WHO ladder is an option after weighing a drug's risks and benefits in individual patients. Symptomatic treatment of severe cancer pain should begin with an opioid, regardless of the mechanism of the pain. They are very effective analgesics, titrate easily, and offer a favorable risk/benefit ratio. Cancer pain remains inadequately controlled despite the diagnostic and therapeutic means of ensuring that patients feel comfortable during their illness. Therefore, all practitioners need to make control of cancer pain a professional duty, even if they can only use the most basic and least expensive analgesic medications, such as morphine, codeine, and acetaminophen, to reduce human suffering.

Opioids and the treatment of chronic pain: controversies, current status, and future directions

Opioids have been regarded for millennia as among the most effective drugs for the treatment of pain. Their use in the management of acute severe pain and chronic pain related to advanced medical illness is considered the standard of care in most of the world. In contrast, the long-term administration of an opioid for the treatment of chronic noncancer pain continues to be controversial. Concerns related to effectiveness, safety, and abuse liability have evolved over decades, sometimes driving a more restrictive perspective and sometimes leading to a greater willingness to endorse this treatment. The past several decades in the United States have been characterized by attitudes that have shifted repeatedly in response to clinical and epidemiological observations, and events in the legal and regulatory communities. The interface between the legitimate medical use of opioids to provide analgesia and the phenomena associated with abuse and addiction continues to challenge the clinical community, leading to uncertainty about the appropriate role of these drugs in the treatment of pain. This narrative review briefly describes the neurobiology of opioids and then focuses on the complex issues at this interface between analgesia and abuse, including terminology, clinical challenges, and the potential for new agents, such as buprenorphine, to influence practice.

Antidiabetic prescriptions and glycemic control in German patients with type 2 diabetes mellitus: a retrospective database study

OBJECTIVES

This study examined patterns of antidiabetic treatment among individuals with type 2 diabetes in Germany and investigated potential differences in attainment of glycemic control associated with the use of specific antidiabetic regimens.

METHODS

This was a retrospective database study. Data were obtained from the German IMS Disease Analyzer-MediPlus database. Patients aged >or=20 years who were identified as having type 2 diabetes and who underwent glycosylated hemoglobin (HbA(1c)) testing at least once between April 1, 2004, and December 31, 2004, were included in the analyses. Potential associations between age, sex, and diabetic complications and the use of specific antidiabetic medications were examined. Also examined were potential associations between attainment of the HbA(1c) target for glycemic control (56.5%), particular patient characteristics, and the use of specific antidiabetic medications.

RESULTS

The study included data from 5135 patients with type 2 diabetes (mean age, 67 years; 2702 men, 2433 women; mean [SD] HbA(1c), 6.9% [1.2%]). The most commonly diagnosed comorbidities were hypertension (66.5%) and obesity (18.7%). There were no significant differences in mean age, sex, or comorbidities between patients categorized by HbA(1c) values <or=56.5% or >6.5%. The most commonly prescribed antidiabetic medications were metformin (20.4%), a sulfonylurea (11.7%), and oral combination therapy (10.9%). In the assessment of potential associations between selected patient characteristics and the receipt of specific antidiabetic medications, individuals were less likely to receive metformin monotherapy if they were aged >or=75 years (12.0%, compared with 21.4% of those aged 65-74 years and 24.7% of those aged <65 years; P < 0.001) or had a diagnosis of a diabetic complication (15.9%, compared with 21.2% in those without complications; P < 0.001). Among those who were more likely to receive insulin monotherapy were women (11.5%, compared with 9.6% of men; P = 0.025) and patients with diabetic complications (13.9%, compared with 9.8% of those without complications; P < 0.001). More than half (52.7%) of patients did not attain the HbA(1c) target. There were significant differences between patients attaining the HbA(1c) target and receipt of specific antidiabetic medications (P < 0.001). Patients treated with insulin monotherapy or oral plus insulin combination therapy were least likely to reach the HbA(1c) target (26.4% and 22.9%, respectively, attained glycemic control; both, P < 0.001). Only 179 (31.9%) of 562 patients treated with oral combination therapy achieved the HbA(1c) target (P < 0.001).

CONCLUSIONS

Over half of these German patients with type 2 diabetes failed to attain the HbA(1c) target for glycemic control. Patients who were prescribed insulin monotherapy or combination therapy were least likely to achieve the target.