Searching for success: Development of a combined patient-reported-outcome ("PRO") criterion for operationalizing success in multi-modal pain therapy.

BACKGROUND: There is a need for a way to measure success in multi-modal pain therapy that researchers and clinicians can agree upon. According to developments in health services research, operationalizing success should take patient-reported outcomes into account. We will present a success criterion for pain therapy that combines different patient-reported variables and includes validity measures. The usable criterion should be part of a statistically significant and satisfactory model identifying predictors of successful pain therapy. METHODS: Routine data from 375 patients treated with multi-modal pain therapy from 2008 to 2013 were used. The change scores of five constructs were used for the combined success criterion: pain severity, disability due to pain, depressiveness, and physical- and mental-health-related quality of life. According to the literature, an improvement of at least ½ standard deviation was required on at least four of the five constructs to count as successful. A three-step analytical approach including multiple binary logistic regression analysis was chosen to identify the predictors of therapy success with the success criterion as the dependent variable. RESULTS: A total of 58.1% of the patients were classified as successful. Convergent and predictive validity data show significant correlations between the criterion and established instruments, while discriminative validity could also be shown. A multiple binary logistic regression analysis confirmed the feasibility; a significant model (Chi(2) (8) = 52.585; p < .001) that explained 17.6% of the variance identified the following predictors of therapy success: highest pain severity in the last 4 weeks, disability due to pain, and number of physician visits in the last 6 months. CONCLUSIONS: It is possible to develop a feasible success criterion that combines several variables and includes patient-reported outcomes ("PROs") with routine data that can be used in a predictor analysis in multi-modal pain therapy. The criterion was based on basic constructs used in pain therapy and used widespread validated self-rating instruments. Thus, it should be easy to transfer this criterion to other institutions.

Higher pain scores, similar opioid doses and side effects associated with antipyretic analgesics in specialised tertiary pain care.

PURPOSE: To evaluate whether non-opioid antipyretic analgesics are associated with lower pain scores, opioid doses and side effects in pain patients in tertiary care. METHODS: In a cross-sectional observational study, data from 519 Caucasians (197 men, 322 women; mean age 55.6 ± 15 years) who had undertaken pain therapy for various causes for 77.5 ± 90.8 months, obtained in three separate study centres, was analysed for actual 24-h pain scores, daily opioid doses and the occurrence of side effects. RESULTS: Of the 519 patients, 352 received opioids and 260 antipyretic analgesics, from whom 154 received both classes and 304 only either class. The administration of non-opioid antipyretic analgesics was associated with higher average pain scores (4.6 ± 2.5 vs 3.9 ± 2.6; P = 0.01), tendentially higher average oral morphine equivalent doses (121.8 ± 162.2 vs 146.7 ± 242.4 mg/d; P = 0.25) and a similar incidence of side effects (P = 0.21). These results were correspondingly seen when analysing the three study centres separately as independent cohorts. CONCLUSIONS: With the caution advised for cross-sectional data, the results dispute a clinical benefit of non-opioid antipyretic analgesics for most chronic pain patients in tertiary care and draw attention towards prospectively re-evaluating the utility of non-opioid antipyretic analgesics in tertiary pain care in a randomised placebo controlled trial.

Long-term treatment of neuropathic pain with a 5% lidocaine medicated plaster.

BACKGROUND AND OBJECTIVE: The 5% lidocaine medicated plaster is a topical treatment for peripheral neuropathic pain symptoms (e.g. burning, shooting and stabbing pain) and is registered for the treatment of postherpetic neuralgia. This study examined the efficacy and tolerability of long-term treatment with the 5% lidocaine medicated plaster in patients with localized neuropathic pain conditions. METHODS: Twenty patients with localized neuropathic pain [postoperative neuropathic pain (n = 14); complex regional pain syndrome (n = 2); and postherpetic neuralgia (n = 4)], who had been successfully treated with 5% lidocaine medicated plaster, were followed up by telephone interview after 3 and 5 years. Questions were related to the efficacy, development of tolerance, tolerability, wear time and comfort of the plaster. RESULTS: At 3 years, 10 out of 20 (50%) initial responders were still using the plasters with no decline in analgesic efficacy. After 5 years, eight of the original 20 responders (40%) maintained treatment and continued to experience effective pain relief. The 12 responders who discontinued treatment did so because they no longer required analgesic therapy (n = 4); their health insurer refused to fund treatment (n = 2); they were lost to follow-up (n = 1); or had died from an illness unrelated to plaster treatment (n = 5). No patient discontinued because of inadequate analgesia or intolerable side effects. Reversible erythema occurred in two patients wearing the plaster for more than 16 h. There were no systemic side effects. CONCLUSION: The 5% lidocaine medicated plaster provides sustained pain relief over long-term treatment in patients with neuropathic pain of various causes and is well tolerated.

Consensus and Controversies Between Pain and Addiction Experts on the Prevention, Diagnosis, and Management of Prescription Opioid Use Disorder.

OBJECTIVES: Prescription opioid use disorder (POUD) is an established public health crisis in many countries, and current evidence indicates it is a growing problem in Europe. Many specialists play a role, including pain and addiction medicine specialists, in the diagnosis and management of POUD, but neither group can fully address these patients' needs alone. The purpose of this consensus process was to bring together experts from pain and addiction medicine to examine the positions of both specialties. METHODS: In all, 13 international pain medicine, addiction medicine, and addiction psychiatry experts convened a meeting to formulate a set of consensus statements on the diagnosis and management of POUD. The statements were further refined by a wider group of 22 European expert clinicians. At a second meeting of all 35 participants, a set of controversy statements was also developed to recognize some of the key areas of divergent opinion. RESULTS/CONCLUSIONS: There was a high level of agreement between pain and addiction specialists. Key themes that emerged were the need to strengthen interdisciplinary communication, a desire for greater education and training for clinicians in both specialties, and mutual acknowledgment of the importance of multidisciplinary management of POUD. The blurred line between poorly managed pain and POUD was also a subject of much discussion, reflecting the difficulties in defining and diagnosing this complex condition.

Effectiveness of an intensive multidisciplinary headache treatment program.

OBJECTIVE: To investigate if the effectiveness of a 96-hour multidisciplinary headache treatment program exceeds the effectiveness of a 20-hour program and primary care. BACKGROUND: When dealing with chronic back pain, low-intensity multidisciplinary treatment yields no significantly better results than standard care and monodisciplinary therapy; however, high-intensity treatment does. For multidisciplinary headache treatment, such comparisons are not yet available. In a previous study undertaken by our Pain Center, the outcome of a minimal multidisciplinary intervention model (20-hour) did not exceed primary care. METHODS: Forty-two patients suffering from frequent headaches (20 +/- 9 headache days/month; range: 8-30) were treated and evaluated in a 96-hour group program. The results were compared with the outcomes of the previous study. Subjects who had undergone either the 20-hour multidisciplinary program or the primary care were used as historical control groups. FINDINGS: A significant reduction in migraine days (P < .001), tension-type headache days (P < .001), frequency of migraine attacks (P = .004), and depression score (P < .001) was seen at the follow-up after 22 (+/-2) weeks. Comparing the intensive multidisciplinary program with primary care, repeated measures ANOVAs revealed significant time x group interactions for migraine days (P = .020), tension-type headache days (P = .016), and frequency of migraine attacks (P = .016). In comparison with the 20-hour multidisciplinary program, the 96-hour program showed significantly better effects only in the reduction of migraine days (P = .037) and depression score (P = .003). The responder-rates (> or =50% improvement) in the 96-hour program were significantly higher than in the 20-hour program (migraine days, P = .008; tension-type headache days, P = .044) and primary care (migraine days, P = .007; tension-type headache days, P = .003; tension-type headache intensity, P = .037). The effect sizes were small to medium in the 96-hour program. Particularly with the reduction of migraine symptomatology, the 96-hour program performed better than the 20-hour program, which produced only negligible or small effects. CONCLUSIONS: Intensive multidisciplinary headache treatment is highly effective for patients with chronic headaches. Furthermore, migraine symptomatology responds especially well to this intensive treatment program, whereas effects on tension-type headaches were realized by both multidisciplinary programs. Randomized controlled trials and subgroup analysis are needed to find out if these results can be replicated and which patient characteristics allow for sufficient improvements for headache sufferers even with less complex treatment.

Prevalence and Determinants of Painful and Painless Neuropathy in Type 1 Diabetes Mellitus.

Aims: To evaluate (1) the prevalence of diabetic distal symmetrical sensory-motor polyneuropathy (DSPN) and painful DSPN among patients with type 1 diabetes mellitus (DM1) aged over 18 years and (2) the determinant factors of neuropathy and pain in those patients. Materials and Methods: An epidemiological, cross-sectional, observational study was performed; 330,386 people were included, and a total of 444 people were diagnosed with DM1. After exclusion of possible confounders, 360 patients were assessed for painless and painful DSPNs using neurological examination and questionnaires for neuropathy and pain. Odds ratio (OR) and confidence intervals (95% CI) were estimated using multinomial logistic regression models. The analysis was based on a framework with four conceptual levels that consider feasible pathways between several risk factors: (1) socio-demographic factors and diabetes duration, (2) patient habits, (3) co-morbidities, and (4) metabolic factors and disease complications. Results: The prevalence of DSPN and painful DSPN were 42.8 and 18.9%, respectively. Diabetes duration was positively associated with painful (OR = 1.107, 95% CI: 1.107-1.139) and painless DSPN (OR = 1.069, 95% CI: 1.043-1.096). Education level was negatively associated with painful DSPN (OR = 0.889, 95% CI: 0.826-0.957). Sex (female) was positively associated only with painless DSPN (OR = 1.769, 95% CI: 1.007-3.107). Being a current or former smoker was positively associated only with painless DSPN (OR = 1.940, 95% CI: 1.069-3.518). Hypertension was positively associated with painful DSPN (OR = 2.474, 95% CI: 1.110-5.512) and painless DSPN (OR = 2.565, 95% CI: 1.252-5.256). Glycated hemoglobin (HbA1c) was positively associated only with painless DSPN (OR = 1.193, 95% CI: 1.018-1.399). Conclusions: Diabetes duration and hypertension have a direct impact on the development of painful and painless DSPN. However, female sex and HbA1c have a direct effect only on the development of painless DSPN, and education level has an indirect effect on the development of painful DSPN. Therefore, it can be concluded that different etiological factors have different contributions to the development of neuropathy and pain.

Transdermal buprenorphine patches applied in a 4-day regimen versus a 3-day regimen: a single-site, Phase III, randomized, open-label, crossover comparison.

BACKGROUND: In 2001, a transdermal matrix patch formulation of buprenorphine was approved for the treatment of moderate to severe cancer pain and severe pain that is unresponsive to nonopioid analgesics. The primary recommendation contained in the prescribing information was that transdermal patches be worn for a 3-day period before application of a new patch. OBJECTIVE: This study was conducted to evaluate the potential for extending the time the buprenorphine patch is worn from 3 to 4 days. METHODS: This single-center, randomized, open-label, crossover Phase III study compared the efficacy and tolerability of the buprenorphine transdermal patch applied for different durations, with patch changes every 3 days versus every 4 days (12 days each), in patients with chronic moderate or severe pain of malignant or nonmalignant origin. Study participants were aged >18 years, had already responded to at least 4 weeks of transdermal buprenorphine, and had achieved steady-state conditions for at least 2 weeks before enrollment. The primary end point was patients' rating of the quality of treatment (analgesic efficacy and tolerability, rated on a 5-point scale: very good, good, satisfactory, poor, and inadequate) at the completion of each treatment regimen. Also recorded were physicians' ratings of the quality of treatment; pain intensity, rated on an 11-point numerical rating scale (from 0 = no pain to 10 = worst pain imaginable) and on the McGill Pain Questionnaire (MPQ) (maximum pain = 3.0); health status, assessed using the 36-item Short Form Health Survey (SF-36), expressed as a percentage of the best health condition (100%); and pain relief (5-point scale: complete, good, satisfactory, slight, and none). Local skin tolerability was evaluated for objective and subjective dermatologic symptoms at the patch application sites. Patients recorded daily pain intensities at specified times of day and night, pain relief (5-point verbal rating scale), and sleep duration (2-3 hours, >3-<6 hours, or >or=6 hours) in a diary. The safety profile was evaluated based on standard monitoring of adverse events, vital signs, and routine laboratory tests. RESULTS: Forty-nine white patients (25 women, 24 men) were enrolled; their mean (SD) age was 61.6 (11.5) years, and their mean weight was 74.7 (16.7) kg. The most common source of pain was musculoskeletal disorders (40 patients), followed by nervous system disorders (10), neoplasms (9), injuries (5), and other causes (6). Forty-one patients completed the study; 2 patients discontinued because of adverse events, 1 because of lack of efficacy, and 5 for nonmedical reasons. Thirty-three patients provided data per protocol. Patients in the perprotocol population received a mean (SD) transdermal buprenorphine dose of 49.9 (38.9) microg/h. The proportion of patients in the per-protocol population rating the quality of treatment as adequate (combined ratings of very good, good, and satisfactory) was 93.9% (31/33) for both regimens. The physicians' ratings indicated adequate quality of treatment in 93.8% (30/32) of patients applying 4 patches for 3 days each and 97.0% (32/33) of patients applying 3 patches for 4 days each. Mean (SD) pain intensity scores on the numerical rating scale were similar after completion of the 3- and 4-day regimens (3.73 [1.88] and 3.88 [1.75] points, respectively), as were MPQ scores (0.79 [0.67] and 0.79 [0.78]). The mean (SD) proportion of days with at least satisfactory pain relief was 83.9% (26.1%) and 85.6% (24.4%) for the 3- and 4-day regimens; the corresponding proportions of nights with at least satisfactory pain relief were 85.2% (26.6%) and 88.1% (21.4%). Continuously assessed pain intensities at specified times of day and night (numerical rating scale) did not differ significantly between regimens. Mean SF-36 health status scores did not differ significantly between regimens (total score: 37.7% [17.0%] and 37.7% [17.3%]). Mean rates of nights with good sleep quality were 28.5% (39.9%) for the 3-day regimen and 36.0% (42.6%) for the 4-day regimen. Local skin tolerability was comparable for the 3- and 4-day regimens, with objective findings (mainly erythema) at the patch-application sites in 17 of 32 and 11 of 33 patients, respectively, and subjective symptoms (mainly itching) in 16 of 32 and 13 of 33 patients. The most common adverse events in the safety population were nausea, dizziness/giddiness, and malaise/fatigue (3/49 [6.1%] each). CONCLUSION: Analgesic efficacy, patients' satisfaction with the quality of treatment, and skin tolerability did not differ significantly between 3 and 4 days of patch application in these patients with chronic pain who had been previously stabilized on transdermal buprenorphine.

Psychological Predictors of Acute Postoperative Pain After Hysterectomy for Benign Causes.

OBJECTIVES: Psychological parameters have been shown to contribute significantly to the development of acute postoperative pain (APOP). For the prediction of APOP in chest malformation patients and cancer patients, we found pain-specific psychological predictors to be of higher relevance than general psychological predictors. The current study aims to further substantiate these findings. MATERIALS AND METHODS: In a sample of 73 middle-aged hysterectomy patients, 3 predictor sets were assessed 1 day before surgery: attentional biases (toward pain-related, social threat, and positive words in a dot-probe task), pain-related emotions and cognitions (pain anxiety, pain catastrophizing, and pain hypervigilance), and affective state variables (depression and somatization). APOP intensity rated 2 to 3 days after surgery and analgesic consumption during the first 48 postoperative hours were used as outcome measures. RESULTS: APOP intensity ratings were significantly explained by their best single predictors in a multiple regression analysis: social threat words of the dot-probe task, pain anxiety, and somatization (14.7% of explained variance). When comparing standardized ß coefficients, pain-specific psychological predictors appeared to be of higher explanatory relevance than general psychological predictors. In contrast, analgesic consumption could not be significantly predicted by the psychological variables. DISCUSSION: Hysterectomy patients at risk for high APOP intensity could be characterized by the psychological variables used, whereas their predictive value for analgesic consumption was limited. The high predictive potency of pain-specific psychological variables should be considered for further improvement of pain management and prevention, because pain-specific variables such as pain anxiety can be the target of focal psychological interventions when preparing for surgery.

Long-term management of chronic pain with transdermal buprenorphine: a multicenter, open-label, follow-up study in patients from three short-term clinical trials.

BACKGROUND: Transdermal buprenorphine is available in Europe for the treatment of moderate to severe chronic pain. It has been evaluated at doses of 35, 52.5, and 70 microg/h for the management of moderate to severe chronic cancer and noncancer pain in 3 randomized, double-blind, placebo-controlled trials, each of limited duration (approximately 14 days each). Long-term data are essential to determining the performance of an analgesic in the management of chronic pain. OBJECTIVE: The purpose of this follow-up study was to obtain data on the efficacy and tolerability of long-term treatment with transdermal buprenorphine in cancer and noncancer patients with chronic persistent pain of moderate to severe intensity. METHODS: This was an open-label, uncontrolled, follow-up study in patients from the 3 previous clinical trials who elected to continue treatment with transdermal buprenorphine 35 microg/h and sublingual buprenorphine tablets (0.2 mg) as needed for breakthrough pain. The patch was to be changed every 72 hours throughout the patient's course of pain therapy. At visits every 2 weeks for the first 4 weeks and every 4 weeks for the remainder of study participation, patients evaluated their pain relief retrospectively on a 4-point verbal rating scale. They also rated the ease of patch handling using a 3-point verbal rating scale. Patterns of dose escalation and dose stability were monitored over time. Adherence to therapy was determined based on the number of patients who complied with the dosing schedule. Adverse events were documented by type, intensity, location (systemic or local), and relationship to study medication. RESULTS: Two hundred thirty-nine patients were included in this follow-up study (120 women, 119 men; 100% white; mean [SD] age, 58 [11.3] years; mean weight, 70.8 [14.7] kg). One hundred thirty-four had cancer-related pain and 105 had pain of noncancerous origin. The mean duration of participation was 7.5 months, and 37 (15.5%) patients participated for >12 months. Maximum study participation was 3.4 years in cancer patients and 5.7 years in noncancer patients. One hundred eighty-eight (78.7%) patients were considered adherent to therapy. The majority (65.9%) of patients managed their pain with the patchalone or took no more than 1 additional sublingual tablet daily for breakthrough pain. At least satisfactory pain relief was reported by 215 (90.0%) patients, and the buprenorphine patch was generally well tolerated. The most common systemic adverse drug reactions were nausea (9.2%), dizziness (4.6%), vomiting (4.2%), constipation (3.8%), and tiredness (2.9%), whereas the most common local adverse drug reactions were erythema (12.1%), pruritus (10.5%), and exanthema (8.8%). CONCLUSION: Transdermal buprenorphine was generally well tolerated and effective for the long-term treatment of chronic cancer or noncancer pain in these patients who had previously received buprenorphine in 3 short-term clinical trials.

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

BACKGROUND: Previous studies have suggested that buprenorphine may have a low association with tolerance development compared with other strong opioids. In a previous study by our group, mean cohort and intraindividual dosage increases over an entire course of treatment and on a per-day basis were significantly lower with transdermal (TD) buprenorphine than with TD fentanyl. However, no information concerning the relationship between qualitative and quantitative dose changes is available. OBJECTIVE: The aim of this study was to compare TD buprenorphine and TD fentanyl with respect to dosage increases, dosage stability, and the nature of dosage changes. METHODS: This retrospective analysis used data from the IMS Disease Analyzer-Mediplus database, which contains patient-related data documented by 400 medical practices in Germany. Data from patients with noncancer or cancer pain treated with TD buprenorphine or TD fentanyl for at least 3 months between May 2002 and April 2005 were analyzed. Daily dosages were directly determined from the prescribed patch strength, taking into account the possibility of multiple patches applied simultaneously. To determine dosage stability, patients were classified based on the type of dosage change (stable, increase, alternating, or decrease) of the prescribed dosages. From the prescribed daily dosages, mean percentage increases were calculated on a per-patient basis for the entire treatment period and per day, and these were assessed in relation to the type of dosage change. RESULTS: In total, 631 patients with noncancer pain and 605 patients with cancer pain were included in the analysis (782 women, 454 men; mean age, 76.3 years [range, 29-100 years]). Treatment indications included osteoarthritis, low back pain, osteoporosis (noncancer groups), and neoplasm (cancer groups). Patients had similar analgesic premedication requirements based on steps 1 to 3 of the World Health Organization analgesic ladder. Comedication requirements for breakthrough pain were also similar between the TD buprenorphine and TD fentanyl groups. The mean percentage increases per day were 0.10% (TD buprenorphine) and 0.25% (TD fentanyl) in the noncancer groups and 0.19% (TD buprenorphine) and 0.47% (TD fentanyl) in the cancer groups (both, P < 0.05). A significantly larger proportion of patients receiving TD buprenorphine had stable dosages over the entire treatment period compared with patients receiving TD fentanyl (noncancer groups: 56.9% vs 41.6%; cancer groups: 50.0% vs 26.2% [both, P < 0.05]). Compared with TD buprenorphine, the proportion of patients with alternating dosage changes was significantly greater in patients receiving TD fentanyl (noncancer groups: 22.7% vs 13.1%; cancer groups: 30.6% vs 11.8% [both, P < 0.05]). CONCLUSIONS: In this retrospective data analysis, compared with TD buprenorphine, the increase in mean daily dosage was significantly greater in patients treated with TD fentanyl. Also, compared with TD buprenorphine, alternating dosage changes were seen in a significantly greater proportion of patients receiving TD fentanyl. On the other hand, a significantly greater proportion of patients treated with TD buprenorphine had stable dosages over their entire treatment periods.

Pharmacokinetic and pharmacodynamic properties of tramadol IR and SR in elderly patients: a prospective, age-group-controlled study.

BACKGROUND: Tramadol is widely prescribed, even to the eldest patients. Although age-related differences in pharmacologic responsiveness are to be expected, the pharmacodynamic and pharmacokinetic (PK) properties of tramadol have not been systematically compared between patients of various ages. OBJECTIVE: The aim of this study was to explore the effectiveness, PK properties, and safety profile of 2 galenic tramadol formulations in 3 similarly sized age groups with malignant and nonmalignant pain of moderate to severe intensity. METHODS: This prospective, age-group-controlled study was conducted at the ambulatory pain clinic of the Landeskrankenhaus Kärnten, Klagenfurt, Austria. Male and female adults with malignant and nonmalignant pain of moderate to severe intensity were eligible. Patients were stratified into similarly sized age groups, as follows: >or=75, 65-<75, and <65 years. Patients first received the immediate-release galenic formulation of tramadol (tramadol IR) until steady state was achieved, followed by the sustained-release formulation (tramadol SR) until steady state. Serum concentrations of tramadol and its active metabolite (O-desmethyl-tramadol [M1]) were measured using gas chromatography to estimate the age-related PK handling of the analgesic drug. Three validated scales were used to measure pain intensity during the study: a 100-mm visual analog scale (VAS), an 11-point numeric analog scale (NAS), and a 4-point verbal rating scale (VRS). Tolerability was assessed by evaluating daily answers about the potential occurrence of adverse events (and respective details such as type and severity) from baseline until the end of the observation period. RESULTS: A total of 100 patients were enrolled (58 women, 42 men; mean [SD] age, 65.2 [15.0] years; >or=75, 30 patients; 65-<75, 31 patients; and <65 years, 39 patients). Predominant causes of pain were neoplasms (27.4% of causes) and injury and other external causes (20.8%), and diseases of the musculoskeletal and connective-tissues systems (19.8%). Fifty-five patients completed the study and provided all data as planned. Mean (SEM) steady-state tramadol IR doses were 250 (20.2), 277 (39.8), and 325 (33.1) mg/d in patients aged >or=75, 65-<75, and 65 years, respectively (P = NS); tramadol SR, 278 (27.5), 306 (39.7), and 340 (35.1) mg/d (P = NS). Serum concentrations of tramadol and M1 were statistically similar across all 3 age groups. Overall, mean pain intensity scores, as measured using the VAS and NAS, were decreased from baseline (62.4 [2.0] mm and 6.22 [0.22] points, respectively) to steady state with tramadol IR (23.6 [2.9] mm and 2.65 [0.30] points) and tramadol SR (16.9 [2.5] mm and 1.91 [0.26] points) (all, P < 0.001). Pain intensity before and improvements during both treatment phases were similar across all 3 age groups. RESULTS: for pain intensity on the VRS also did not find age-related differences. The predominant adverse effects were nausea (27.0% of patients), dizziness and giddiness (18.0%), and malaise and fatigue (15.0%); no significant differences in adverse events were found between age groups. CONCLUSIONS: The fate of tramadol and its active metabolite, and their clinical effects, have been examined here for the first time in a prospective cohort study, which compared patients aged <65 years, 65-<75 years, and >or=75 years. In contrast to expectations, it was concluded that tramadol IR and tramadol SR were both generally well tolerated and effective in the treatment of moderate to severe pain in any of the 3 age groups in these patients. Although the eldest group of patients consumed, on average, 20% less tramadol (P = NS) than the youngest group, the PK properties of both drugs were not changed when given to elderly patients.

Effects of intermittent hemodialysis on buprenorphine and norbuprenorphine plasma concentrations in chronic pain patients treated with transdermal buprenorphine.

The present study was designed to study the impact of intermittent hemodialysis on the disposition of the partial agonist buprenorphine and its metabolite norbuprenorphine during therapy with transdermal buprenorphine in chronic pain patients with end-stage kidney disease. Ten patients (mean age 63 years) who had received transdermal buprenorphine for at least 1 week, were asked to provide blood samples immediately before and after hemodialysis. Blood samples were analysed for buprenorphine and its metabolite norbuprenorphine. The median buprenorphine plasma concentrations were found to be 0.16 ng/ml before and 0.23 ng/ml after hemodialysis. A significant correlation between plasma levels and administered doses was observed (Spearman R=0.74; P<0.05). In three patients norbuprenorphine plasma levels were detected. No differences in pain relief before and after hemodialysis were observed. This investigation shows no elevated buprenorphine and norbuprenorphine plasma levels in patients with renal insufficiency receiving transdermal buprenorphine up to 70 microg/h. Furthermore, hemodialysis did not affect buprenorphine plasma levels, leading to stable analgesic effects during the therapy.

Different profiles of buprenorphine-induced analgesia and antihyperalgesia in a human pain model.

Different mechanisms were proposed for opioid-induced analgesia and antihyperalgesia, which might result in different pharmacodynamics. To address this issue, the time course of analgesic and antihyperalgesic effects of intravenous (i.v.) and sublingual (s.l.) buprenorphine was assessed in an experimental human pain model. Fifteen volunteers were enrolled in this randomized, double-blind, and placebo controlled cross-over study. The magnitude of pain and the area of secondary hyperalgesia following transcutaneous stimulation were repetitively assessed before and up to 150 min after administration of (1) 0.15 mg buprenorphine i.v. and placebo pill s.l., (2) 0.2 mg buprenorphine s.l. and saline 0.9% i.v. or (3) saline 0.9% i.v. and placebo pill s.l. as a control. The sessions were separated by 2 week wash-out periods. For both applications of buprenorphine the antihyperalgesic effects were more pronounced as compared to the analgesic effects (66+/-9 vs. 26+/-5% and 43+/-10 vs. 10+/-6%, for i.v. and s.l. application, respectively). This contrasts the pattern for the intravenous administration of pure mu-receptor agonists in the same model in which the antihyperalgesic effects are weaker. The apparent bioavailability of buprenorphine s.l. as compared to buprenorphine i.v. was 58% with a 15.8 min later onset of antinociceptive effects. The half-life of buprenorphine-induced analgesic and antihyperalgesic effects were 171 and 288 min, respectively. In contrast to pure mu-receptor agonists, buprenorphine exerts a lasting antihyperalgesic effect in our model. It will be of major clinical interest whether this difference will translate into improved treatment of pain states dominated by central sensitization.

Equipotent doses of transdermal fentanyl and transdermal buprenorphine in patients with cancer and noncancer pain: results of a retrospective cohort study.

BACKGROUND: The equipotency ratio of transdermal (TD) fentanyl to oral morphine has been established as 1:100; for buprenorphine TD, a ratio of 1:75 has been proposed, although this ratio has not been confirmed in clinical studies. Growing evidence from clinical practice, in which much lower doses of buprenorphine are used, suggests that this conversion ratio may be too high. OBJECTIVE: The aim of this study was to compare calculated equipotent oral morphine doses of fentanyl TD with equipotent oral morphine doses of buprenorphine TD prescribed in clinical practice. METHODS: This retrospective study identified patients with cancer and noncancer pain who had received > or =1 prescription for fentanyl TD or buprenorphine TD (the all-patients groups) from the German IMS Disease Analyzer-mediplus database, which contains all relevant data concerning drug prescriptions from 400 practices in Germany. Also identified were subgroups of the all-patients groups who had received long-term treatment with fentanyl TD or buprenorphine TD and were considered to have similar pain intensity, as they had previously received similar analgesic medication (the identical-cohort groups). Mean prescribed daily doses for the all-patients and identical-cohort groups were calculated based on the distribution of prescribed patch strengths. Because patients could have applied >1 patch, mean prescribed daily doses were also calculated based on an assumption of double application when appropriate. Equipotent oral morphine doses were estimated using equipotency ratios of 1:100 for fentanyl TD and 1:75 for buprenorphine TD. RESULTS: The all-patients groups consisted of 2198 patients with noncancer pain and 2544 patients with cancer pain; the identical-cohort groups consisted of 380 patients with noncancer pain and 496 patients with cancer pain (529 women, 347 men; mean age, 74 years [range, 25-101 years]). Equipotent doses of oral morphine were significantly lower in patients receiving buprenorphine TD compared with those receiving fentanyl TD (P < 0.001). In cancer patients, the equipotent oral morphine doses of fentanyl TD and buprenorphine TD were 130.9 to 138.9 mg and 85.2 to 88.8 mg, respectively; in noncancer patients, the corresponding values were 117.0 to 118.3 mg and 80.2 to 80.9 mg. Based on these results, an equipotency ratio of 1:110 to 1:115 for buprenorphine TD would appear to be more appropriate than the proposed ratio of 1:75. CONCLUSIONS: The fact that this retrospective analysis conducted in identical cohorts showed lower calculated equipotent oral morphine doses in the buprenorphine TD groups compared with the fentanyl TD groups calls into question the proposed 1:75 ratio for conversion of buprenorphine TD to equipotent oral morphine doses. Based on the findings of the present study, an equipotency ratio of 1:110 to 1:115 may be more appropriate. However, confirmative data from prospective randomized clinical trials are needed.

Changes in the prescribed daily doses of transdermal fentanyl and transdermal buprenorphine during treatment of patients with cancer and noncancer pain in Germany: results of a retrospective cohort study.

BACKGROUND: During long-term therapy with strong opioids (step III opioids according to the World Health Organization [WHO] analgesic ladder), dose increases are often necessary because of deterioration of the primary disease or development of tolerance. OBJECTIVE: The purpose of this study was to compare changes in dosages of transdermal (TD) fentanyl and TD buprenorphine in patients with cancer and non-cancer pain. METHODS: In a retrospective study, patients with cancer and noncancer pain being treated with TD fentanyl or TD buprenorphine for at least 3 months between January 2001 and December 2003 were identified from the IMS Disease Analyzer-mediplus database, which contains all patient-related data documented from 400 medical practices in Germany. The indications for treatment were defined according to the International Classification of Diseases, 10th Revision, and included neoplasm (cancer groups), and osteoarthritis, low back pain, and osteoporosis (noncancer groups). The cohort patients were considered to have comparable pain intensity because they had received similar analgesic premedication classified according to steps I to III of the WHO analgesic ladder (cohort groups). The mean prescribed daily doses on first and last prescription were documented, and the mean percentile increases were calculated over the whole treatment duration and per day. Additionally, the mean percentile intraindividual increases (on a per-patient basis) were estimated. RESULTS: The cohort groups consisted of 448 patients with noncancer pain and 446 patients with cancer pain (552 women and 342 men; mean age, 74 years; range, 25-101 years). The mean percentile increases in dosages over the whole treatment duration and adjusted per day were significantly higher in patients taking TD fentanyl (P < 0.05). Differences were even greater for the mean percentile intraindividual increases per day, which totaled 0.42%and 0.17% for cancer patients taking TD fentanyl and TD buprenorphine, respectively; corresponding values were 0.25% and 0.09%in noncancer patients (P < 0.001). CONCLUSIONS: This retrospective analysis showed a significantly higher increase in the mean daily doses of TD fentanyl as compared with TD buprenorphine. The results must be verified in prospective, randomized clinical studies.

Transdermal buprenorphine in clinical practice--a post-marketing surveillance study in 13,179 patients.

OBJECTIVE: The objective of this post-marketing surveillance study was to collect effectiveness and safety data on the labelled use of buprenorphine transdermal patches (Transtec*) under routine clinical conditions. RESEARCH DESIGN AND METHODS: For this open, observational study, patients with moderate to severe cancer or non-cancer pain requiring treatment with an opioid analgesic were recruited at hospitals, outpatient clinics and general practitioners' practices in Germany. Buprenorphine transdermal patches (35 microg/h, 52.5 microg/h or 70 microg/h) were prescribed at physicians' discretion in accordance with the product's Summary of Product Characteristics (SmPC). Patients assessed their pain relief as 'very good', 'good', 'satisfactory', 'poor' or 'no effect'. Investigators were instructed to report all adverse events throughout the observation period. On completion, effectiveness and tolerability were evaluated for the overall study population, cancer and non-cancer patients, and patients < 70 years and > or = 70 years. Other analyses assessed pain relief with respect to previous opioid treatment and increased patch strength, and in patients who remained on their original dose. The total observation time was 9 months, and the average individual documented treatment time was 60.8 days. RESULTS: A total of 13,179 patients were evaluated; 3690 (28%) with cancer pain and 9489 (72%) with non-cancer pain. The most frequent diagnoses in non-cancer patients were musculoskeletal disorders (77%) and neuropathy (23%). In the great majority of cases (78%), treatment was started with the 35 microg/h patch. The initial dose needed to be increased subsequently only in about 18% of subjects. Buprenorphine transdermal patches provided effective, sustained and dose-dependent analgesia in patients with cancer and non-cancer pain, irrespective of the patients' age or pain syndromes. Whereas good or very good pain relief was documented only for 6% of the patients with the initial assessment, this percentage increased to 71% at the first follow-up and 80% at the final assessment. Fewer than 5% of subjects discontinued treatment owing to unsatisfactory pain relief. Altogether, adverse events were documented for 2874 patients (22%), whereas a relationship with trans dermal buprenorphine (adverse drug reactions) was assumed for only 10% (2220 adverse drug reactions in 1330 patients). The tolerability profile was as expected for an opioid and did not vary to a relevant extent with either the patient's age or the cause of pain (cancer or non-cancer). No evidence emerged of any previously unknown side effects. CONCLUSIONS: Buprenorphine transdermal patches are well tolerated and effective in the treatment of chronic cancer and non-cancer pain, irrespective of the patients' age. There was no clinically relevant development of tolerance.

Treatment of localized neuropathic pain of different etiologies with the 5% lidocaine medicated plaster - a case series.

OBJECTIVE: To assess the efficacy and safety of the topical 5% lidocaine medicated plaster in the treatment of localized neuropathic pain. STUDY DESIGN: This was a case series at an Austrian pain clinic, using retrospective analysis. PATIENTS AND METHODS: Data of 27 patients treated for localized neuropathic pain with the 5% lidocaine medicated plaster were retrospectively analyzed. Assessment included changes in overall pain intensity, in intensity of different pain qualities, and of hyperalgesia and allodynia, and changes in sleep quality. RESULTS: Patients (17 female, ten male; mean age 53.4±11.4 years) presented mainly with dorsalgia (16 patients) or postoperative/posttraumatic pain (seven patients); one patient suffered from both. The mean overall pain intensity prior to treatment with lidocaine medicated plaster was 8.4±1.2 on the 11-point Likert scale. In the majority of cases, the lidocaine plaster was applied concomitantly with preexisting pain medication (81.5% of the patients). During the 6-month observation period, overall mean pain intensity was reduced by almost 5 points (4.98) to 3.5±2.6. Substantial reductions were also observed for neuralgiform pain (5 points from 7.9±2.6 at baseline) and burning pain (3 points from 5.2±4.1). Sleep quality improved from 4.6±2.6 at baseline to 5.5±1.8. Stratification by pain diagnosis showed marked improvements in overall pain intensity for patients with dorsalgia or postoperative/posttraumatic pain. The lidocaine plaster was well tolerated. CONCLUSION: Overall, topical treatment with the 5% lidocaine medicated plaster was associated with effective pain relief and was well tolerated.

Association of genetic and psychological factors with persistent pain after cosmetic thoracic surgery.

The genetic control of pain has been repeatedly demonstrated in human association studies. In the present study, we assessed the relative contribution of 16 single nucleotide polymorphisms in pain-related genes, such as cathechol-O-methyl transferase gene (COMT), fatty acid amino hydrolase gene (FAAH), transient receptor potential cation channel, subfamily V, member 1 gene (TRPV1), and δ-opioid receptor gene (OPRD1), for postsurgical pain chronification. Ninety preoperatively pain-free male patients were assigned to good or poor outcome groups according to their intensity or disability score assessed at 1 week, 3 months, 6 months, and 1 year after funnel chest correction. The genetic effects were compared with those of two psychological predictors, the attentional bias toward positive words (dot-probe task) and the self-reported pain vigilance (Pain Vigilance and Awareness Questionnaire [PVAQ]), which were already shown to be the best predictors for pain intensity and disability at 6 months after surgery in the same sample, respectively. Cox regression analyses revealed no significant effects of any of the genetic predictors up to the end point of survival time at 1 year after surgery. Adding the genetics to the prediction by the attentional bias to positive words for pain intensity and the PVAQ for pain disability, again no significant additional explanation could be gained by the genetic predictors. In contrast, the preoperative PVAQ score was also, in the present enlarged sample, a meaningful predictor for lasting pain disability after surgery. Effect size measures suggested some genetic variables, for example, the polymorphism rs1800587G>A in the interleukin 1 alpha gene (IL1A) and the COMT haplotype rs4646312T>C/rs165722T>C/rs6269A>G/rs4633T>C/rs4818C>G/rs4680A>G, as possible relevant modulators of long-term postsurgical pain outcome. A comparison between pathophysiologically different predictor groups appears to be helpful in identifying clinically relevant predictors of chronic pain.

Naloxone provokes similar pain facilitation as observed after short-term infusion of remifentanil in humans.

In contrast to an expected preventive analgesic effect, clinical observations suggest that intraoperatively applied opioids can induce postoperative hyperalgesia. We tested the development of post-infusion hyperalgesia in a newly developed experimental model of electrically induced pain and secondary mechanical hyperalgesia. In a double-blind, placebo controlled, cross-over study, 13 subjects received either saline placebo, remifentanil (0.05 or 0.1 microg/kg/min) or naloxone (0.01 mg/kg). Remifentanil dose-dependently reduced pain and mechanical hyperalgesia during the infusion, but upon withdrawal, pain and hyperalgesia increased significantly above control level (p<0.01 and p<0.05, respectively). Naloxone infusion similarly resulted in increased pain (anti-analgesia) (p<0.001) and mechanical hyperalgesia (p<0.01). Increased pain ratings following withdrawal of remifentanil significantly correlated to anti-analgesia evoked by the mu-opioid antagonist naloxone (p<0.01) and was of similar magnitude, suggesting inhibition of endogenous opioids as an underlying mechanism. In contrast, hyperalgesia after remifentanil was more pronounced than hyperalgesia after naloxone administration and did not correlate to the observed anti-analgesic effects, suggesting the involvement of additional receptors systems other than the endorphin system.

The cyclooxygenase isozyme inhibitors parecoxib and paracetamol reduce central hyperalgesia in humans.

Non-steroidal antiinflammatory drugs (NSAIDs) are known to induce analgesia mainly via inhibition of cyclooxygenase (COX). Although the inhibition of COX in the periphery is commonly accepted as the primary mechanism, experimental and clinical data suggest a potential role for spinal COX-inhibition to produce antinociception and reduce hypersensitivity. We used an experimental model of electrically evoked pain and hyperalgesia in human skin to determine the time course of central analgesic and antihyperalgesic effects of intravenous parecoxib and paracetamol (acetaminophen). Fourteen subjects were enrolled in this randomized, double blind, and placebo controlled cross-over study. In three sessions, separated by 2-week wash-out periods, the subjects received intravenous infusions of 40 mg parecoxib, 1000 mg paracetamol, or placebo. The magnitude of pain and areas of pinprick-hyperalgesia and touch evoked allodynia were repeatedly assessed before, and for 150 min after the infusion. While pain ratings were not affected, parecoxib as well as paracetamol significantly reduced the areas of secondary hyperalgesia to pinprick and touch. In conclusion, our results provide clear experimental evidence for the existence of central antihyperalgesia induced by intravenous infusion of two COX inhibitors, parecoxib and paracetamol. Since the electrical current directly stimulated the axons, peripheral effects of the COX inhibitors on nociceptive nerve endings cannot account for the reduction of hyperalgesia. Thus, besides its well-known effects on inflamed peripheral tissues, inhibition of central COX provides an important mechanism of NSAID-mediated antihyperalgesia in humans.