Evidence-based data on pain relief with antidepressants

Trends in the treatment of fibromyalgia in South Korea between 2011 and 2018: a retrospective analysis of cross-sectional health insurance data

OBJECTIVES

Fibromyalgia treatment trends vary globally; however, the trend in South Korea has not been investigated yet. This study aimed to analyse the fibromyalgia treatment trends in South Korea.

DESIGN

Retrospective, observational study using serial cross-sectional data.

SETTING

The National Patient Samples of the Korean Health Insurance Review & Assessment Service from 2011 to 2018 were used.

PARTICIPANTS

A total of 31 059 patients with fibromyalgia were included in this study. The basic characteristics of the patients were stratified by sex, age and comorbidity. A patient was considered to have a condition if it was recorded as a principal diagnosis at least once in a year.

PRIMARY AND SECONDARY OUTCOME MEASURES

Trends in the types of medical visits and prescribed treatments were investigated and the values are presented as rates per 100 patients. The types of pharmacological treatment were presented according to the existing clinical guidelines. Additionally, combination prescription trends and associated characteristics were investigated.

RESULTS

Of the patients, 66.2% were female. Visits to internal medicine departments showed the most significant increase (2011: 11.34; 2018: 21.99; p<0.001). Non-pharmacological treatment rates declined (physical therapy 2011: 18.11; 2018: 13.69; p<0.001, acupuncture 2011: 52.03; 2018: 30.83; p<0.001). Prescription rates increased for analgesics, relaxants, antiepileptics and antidepressants. Non-steroidal anti-inflammatory drug prescriptions had the highest increase (2011: 27.65; 2018: 40.02; p<0.001). Serotonin-norepinephrine reuptake inhibitor prescriptions showed significant growth (2011: 2.4; 2018: 8.05; p<0.001). Prescription durations were generally longer for women (p<0.001), with higher rate increases in this group. Combinations of ≥3 medication classes increased (2011: 8.2; 2018: 9.64; p=0.041). Women were more likely to receive combination prescriptions (crude OR 1.47 (95% CI 1.29 to 1.68), adjusted 1.18 (95% CI 1.03 to 1.36)).

CONCLUSIONS

Our findings provide basic reference data for the development and application of national guidelines for fibromyalgia.

Atrophy and Inflammatory Changes in Salivary Glands Induced by Oxidative Stress after Exposure to Drugs and Other Chemical Substances: A Systematic Review

Background and Objectives: Oxidative stress is involved in the alterations at the level of salivary glands, being the cause of oral pathologies like xerostomia, periodontitis, gingivitis, leucoplakia, and cancer. It is known that antioxidants can reverse changes induced by drugs or other chemicals in some organs, but the question is whether these substances can reduce or revert the effects of oxidative stress at the salivary gland level. Our aim was to find histopathological data at the level of salivary glands supporting the hypothesis of the reversal of oxidative stress-induced changes after the treatment with substances with antioxidant effect. Materials and Methods: A systematic search was conducted in PubMed, Science Direct, and Springer databases, including research articles on oxidative stress histological aspects and oxidative stress biomarkers induced by drugs or other chemicals on salivary glands. Results: Out of 1756 articles, 25 articles were selected with data on tissue homogenate used for biochemical analysis of oxidative and antioxidative markers, along with routine hematoxylin eosin (HE) and immunohistochemical analysis used for histopathological and immunohistochemical diagnosis. Drugs (antineoplastic drugs, antibiotics, and analgesics), alcohol, heavy metals, and fluoride can cause oxidative stress, resulting in morphological changes in different tissues, including in salivary glands. There are many antioxidants but only a few were evaluated regarding the effects on salivary glands in animal studies, such as hesperidin and selenium, which can reverse the damage induced by cyclophosphamide; 10-dehydrogingerdione (10-DHGD), a compound extracted from ginger, which has a protective effect against the oxidative stress and apoptosis induced by tramadol; and glycyrrhizic acid, which may repair the injuries incurred after the administration of sodium nitrite. Conclusions: Substances such as hesperidin, selenium, 10-dehydrogingerdione, and glycyrrhizic acid are antioxidants with proven restorative effects on salivary glands for the damage induced by oxidative stress after exposure to drugs and other chemical substances; however, demonstrating their similar effects in human salivary glands is challenging.

Antidepressants for hip and knee osteoarthritis

BACKGROUND

Although pain is common in osteoarthritis, most people fail to achieve adequate analgesia. Increasing acknowledgement of the contribution of pain sensitisation has resulted in the investigation of medications affecting pain processing with central effects. Antidepressants contribute to pain management in other conditions where pain sensitisation is present.

OBJECTIVES

To assess the benefits and harms of antidepressants for the treatment of symptomatic knee and hip osteoarthritis in adults.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was January 2021.

SELECTION CRITERIA

We included randomised controlled trials of adults with osteoarthritis that compared use of antidepressants to placebo or alternative comparator. We included trials that focused on efficacy (pain and function), treatment-related adverse effects and had documentation regarding discontinuation of participants. We excluded trials of less than six weeks of duration or had participants with concurrent mental health disorders.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Major outcomes were pain; responder rate; physical function; quality of life; and proportion of participants who withdrew due to adverse events, experienced any adverse events or had serious adverse events. Minor outcomes were proportion meeting the OARSI (Osteoarthritis Research Society International) Response Criteria, radiographic joint structure changes and proportion of participants who dropped out of the study for any reason. We used GRADE to assess certainty of evidence.

MAIN RESULTS

Nine trials (2122 participants) met the inclusion criteria. Seven trials examined only knee osteoarthritis. Two also included participants with hip osteoarthritis. All trials compared antidepressants to placebo, with or without non-steroidal anti-inflammatory drugs. Trial sizes were 36 to 388 participants. Most participants were female, with mean ages of 54.5 to 65.9 years. Trial durations were 8 to 16 weeks. Six trials examined duloxetine. We combined data from nine trials in meta-analyses for knee and hip osteoarthritis. One trial was at low risk of bias in all domains. Five trials were at risk of attrition and reporting bias. High-certainty evidence found that antidepressants resulted in a clinically unimportant improvement in pain compared to placebo. Mean reduction in pain (0 to 10 scale, 0 = no pain) was 1.7 points with placebo and 2.3 points with antidepressants (mean difference (MD) -0.59, 95% confidence interval (CI) -0.88 to -0.31; 9 trials, 2122 participants). Clinical response was defined as achieving a 50% or greater reduction in 24-hour mean pain. High-certainty evidence demonstrated that 45% of participants receiving antidepressants had a clinical response compared to 28.6% receiving placebo (RR 1.55, 95% CI 1.32 to 1.82; 6 RCTs, 1904 participants). This corresponded to an absolute improvement in pain of 16% more responders with antidepressants (8.9% more to 26% more) and a number needed to treat for an additional beneficial effect (NNTB) of 6 (95% CI 4 to 11). High-certainty evidence showed that the mean improvement in function (on 0 to 100 Western Ontario and McMaster Universities Arthritis Index, 0 = best function) was 10.51 points with placebo and 16.16 points with antidepressants (MD -5.65 points, 95% CI -7.08 to -4.23; 6 RCTs, 1909 participants). This demonstrates a small, clinically unimportant response. Moderate-certainty evidence (downgraded for imprecision) showed that quality of life measured using the EuroQol 5-Dimension scale (-0.11 to 1.0, 1.0 = perfect health) improved by 0.07 points with placebo and 0.11 points with antidepressants (MD 0.04, 95% CI 0.01 to 0.07; 3 RCTs, 815 participants). This is clinically unimportant. High-certainty evidence showed that total adverse events increased in the antidepressant group (64%) compared to the placebo group (49%) (RR 1.27, 95% CI 1.15 to 1.41; 9 RCTs, 2102 participants). The number needed to treat for an additional harmful outcome (NNTH) was 7 (95% CI 5 to 11). Low-certainty evidence (downgraded twice for imprecision for very low numbers of events) found no evidence of a difference in serious adverse events between groups (RR 0.94, 95% CI 0.46 to 1.94; 9 RCTs, 2101 participants). The NNTH was 1000.  Moderate-certainty evidence (downgraded for imprecision) showed that 11% of participants receiving antidepressants withdrew from trials due to an adverse event compared to 5% receiving placebo (RR 2.15, 95% CI 1.56 to 2.97; 6 RCTs, 1977 participants). The NNTH was 17 (95% CI 10 to 35).

AUTHORS' CONCLUSIONS

There is high-certainty evidence that use of antidepressants for knee osteoarthritis leads to a non-clinically important improvement in mean pain and function. However, a small number of people will have a 50% or greater important improvement in pain and function. This finding was consistent across all trials. Pain in osteoarthritis may be due to a variety of causes that differ between individuals. It may be that the cause of pain that responds to this therapy is only present in a small number of people. There is moderate-certainty evidence that antidepressants have a small positive effect on quality of life with heterogeneity between trials. High-certainty evidence indicates antidepressants result in more adverse events and moderate-certainty evidence indicates more withdrawal due to adverse events. There was little to no difference in serious adverse events (low-certainty evidence due to low numbers of events). This suggests that if antidepressants were being considered, there needs to be careful patient selection to optimise clinical benefit given the known propensity for adverse events with antidepressant use. Future trials should include alternative antidepressant agents or phenotyping of pain in people with osteoarthritis, or both.

The prevalence of painful physical symptoms in major depressive disorder: A systematic review and meta-analysis of observational studies

BACKGROUND

Painful physical symptoms (PPS) are common in patients with major depressive disorder (MDD), but their prevalence has been mixed. This is a systematic review and meta-analysis of the pooled prevalence of PPS in MDD patients.

METHODS

Systematic literature searches were independently conducted in major databases (PubMed, EMBASE, PsycINFO and Web of Science). Data analyses were conducted using a random-effects model.

RESULTS

A total of 20 studies with 53,852 patients were included. The overall prevalence of PPS in MDD patients was 55.2% (95%CI: 47.9-62.3%), with a point prevalence of 64.2% (95%CI: 53.2-73.8%) and a 12-month prevalence of 57.0% (95%CI: 23.9-84.8%). No significant publication bias was found in this meta-analysis.

CONCLUSION

PPS are common in MDD patients. Considering the negative impact of PPS on daily functioning, effective preventive measures and routine screening should be conducted for MDD patients, and timely treatments should be offered to those in need. Registration number: CRD42020179471.

Dissociative Aggression Triggered by Headache

Headache is generally perceived as a negative symptom focused on oneself. However, there are reports suggesting that patients suffering from pain, especially headache, can be aggressive. The precise nature of the link between headache and aggression is not known. Here, we describe a homicidal attack, triggered by headache, in a middle-aged man. The patient's background and the characteristics of the attack suggested a dissociative behavior. The case shows that headache may be a trigger for homicidal behavior. Case-control studies are needed to determine the prevalence of aggressive tendencies in patients with headache.

A methodological quality assessment of systematic reviews and meta-analyses of antidepressants effect on low back pain using updated AMSTAR

BACKGROUND

Antidepressants are prescribed widely to manage low back pain. There are a number of systematic reviews and meta-analyses which have investigated the efficacy of the treatments, while the methodological quality of them has not been assessed yet. This study aims to evaluate the methodological quality of the systematic reviews and meta-analyses investigating the effect of antidepressants on low back pain.

METHODS

A systematic search was conducted in PubMed, EMBASE, Medline, and Cochrane Library databases up to November 2018. The 16-item Assessment of Multiple Systematic Reviews (AMSTAR2) scale was used to assess the methodological quality of the studies. Systematic reviews and meta-analyses of the Antidepressants treatment effects on low back pain published in English language were included. There was no limitation on the type of Antidepressants drugs, clinical setting, and study population, while non-systematical reviews and qualitative and narrative reviews were excluded.

RESULTS

A total of 25 systematic reviews and meta-analyses were evaluated; the studies were reported between 1992 and 2017. Obtained results from AMSTAR2 showed that 11 (44%), 9 (36%) and 5 (20%) of the included studies had high, moderate and low qualities, respectively. 13(52%) of studies assessed risk of bias and 2(20%) of meta analyses considered publication bias. Also, 16 (64%) of the included reviews provided a satisfactory explanation for any heterogeneity observed in the results.

CONCLUSIONS

Although the trend of publishing high quality papers in ADs effect on LBP increased recently, performing more high-quality SRs and MAs in this field with precise subgroups of the type of pains, the class of drugs and their dosages may give clear and more reliable evidence to help clinicians and policymakers.

Serotonin-evoked cytosolic Ca2+ release and opioid receptor expression are upregulated in articular cartilage chondrocytes from osteoarthritic joints in horses

Osteoarthritis is a pain-associated progressive disease and pain mediators, such as opioid receptors, expressed in articular cartilage could represent novel therapeutic targets. Acute and chronic stages of OA indicate different metabolic abilities of the chondrocytes depending on inflammatory state. This study aimed to investigate the response of healthy and osteoarthritic chondrocytes and their expression and release of pain mediators in response to acute inflammation. Interleukin-1 beta (IL-1β) and lipopolysaccharide (LPS) were used to induce an acute inflammatory response in cultured equine chondrocytes harvested from healthy joints (HC) and osteoarthritic joints (OAC), the latter representing acute exacerbation of a chronic inflammatory state. Intracellular Ca2+ release was determined after exposure to serotonin (5-hydroxytryptamine (5-HT), glutamate or ATP. Protein expression levels of F- and G-actin, representing actin rearrangement, and opioid receptors were investigated. Glutamate concentrations in culture media were measured. Cartilage was immunohistochemically stained for µ (MOR), κ (KOR), and δ (DOR) opioid receptors. Upon exposure to acute inflammatory stimuli, OAC showed increased intracellular Ca2+ release after 5-HT stimulation and increased expression of MOR and KOR. When cells were stimulated by inflammatory mediators, glutamate release was increased in both HC and OAC. Immunostaining for MOR was strong in OA cartilage, whereas KOR was less strongly expressed. DOR was not expressed by cultured HC and OAC and immunostaining of OA cartilage equivocal. We show that chondrocytes in different inflammatory stages react differently to the neurotransmitter 5-HT with respect to intracellular Ca2+ release and expression of peripheral pain mediators. Our findings suggest that opioids and neurotransmitters are important in the progression of equine OA. The inflammatory stage of OA (acute versus chronic) should be taken into consideration when therapeutic strategies are being developed.

Mangiferin: Possible uses in the prevention and treatment of mixed osteoarthritic pain

Osteoarthritis (OA) pain has been proposed to be a mixed pain state, because in some patients, central nervous system factors are superimposed upon the more traditional peripheral factors. In addition, a considerable amount of preclinical and clinical evidence has shown that, accompanying the central neuroplasticity changes and partially driven by a peripheral nociceptive input, a real neuropathic component occurs that are particularly linked to disease severity and progression. Hence, innovative strategies targeting neuroprotection and particularly neuroinflammation to prevent and treat OA pain could be introduced. Mangiferin (MG) is a glucosylxanthone that is broadly distributed in higher plants, such as Mangifera indica L. Previous studies have documented its analgesic, anti-inflammatory, antioxidant, neuroprotective, and immunomodulatory properties. In this paper, we propose its potential utility as a multitargeted compound for mixed OA pain, even in the context of multimodal pharmacotherapy. This hypothesis is supported by three main aspects: the cumulus of preclinical evidence around this xanthone, some preliminary clinical results using formulations containing MG in clinical musculoskeletal or neuropathic pain, and by speculations regarding its possible mechanism of action according to recent advances in OA pain knowledge.

Antidepressant use and its relationship with current symptoms in a population-based sample of older Australians

BACKGROUND

Australia has the second highest per capita users of antidepressants globally, and their use is pronounced in older Australians. A better understanding of antidepressant use in older adults is important because the elderly are often prescribed multiple drugs, without review, for long periods.

METHODS

This study analysed questionnaire data obtained from the Personality and Total Health through life project. Individual respondent data was linked to Pharmaceutical Benefits Scheme (PBS) records. Associations between self-reported medicine use and current symptoms with antidepressant dispensing were examined.

RESULTS

1275 participants aged over 65 were included in the final analysis. One hundred and forty-six (11.5%) participants were dispensed an antidepressant within the specified timeframe. Of those, 38.4% self-reported that they use medicine for depression, 12.3% for anxiety, 17.8% for both depression and anxiety, 6.2% for sleep problems and 3.4% for pain. One fifth of those dispensed an antidepressant did not self-report use of the medicine. Being female or reporting symptoms of depression, anxiety or suicidality were significant predictors of being on an antidepressant. Increasing pain severity was also associated with increased likelihood of being on an antidepressant.

LIMITATIONS

We have presented a cross-sectional analysis, which can only provide associations between current symptoms and medicine use. We have only assessed respondents who received their scripts with PBS concession, which limits generalizability.

CONCLUSION

Our analysis highlights the high use of antidepressants in the elderly for various reasons. Our findings also uncovered a high amount of under-reporting of antidepressant use by respondents.

Scolopendra Pharmacopuncture Ameliorates Behavioral Despair in Mice Stressed by Chronic Restraint

Introduction

Pharmacopuncture, which combines acupuncture with herbal medicine, is one of the newly developed acupuncture techniques that has recently been put into use. The possible mechanisms of scolopendra pharmacopuncture, as well as its potential effects on depressive symptoms, were investigated in this study by using a mouse model of chronic immobilization stress (CIS).

Methods

C57BL/6 male mice were randomly assigned into three groups: mice not stressed with restraint and injected with distilled water, mice stressed with restraint and injected with distilled water, and mice stressed with restraint injected with scolopendra pharmacopuncture at a cervical site. Behavioral tests (an open field test, tail suspension test, and forced swimming test) were carried out after two weeks of CIS and injection treatments. The expression levels of glial fibrillary acidic protein (GFAP) in the hippocampus were determined by using western blot and immunohistochemistry analyses.

Results

Mice exposed to CIS showed decreased behavioral activity, while scolopendra pharmacopuncture treatment significantly protected against the depressive-like behaviors induced by CIS. Moreover, scolopendra pharmacopuncture treatment increased GFAP protein levels in the hippocampi of the mice stressed by chronic immobilization.

Conclusion

Scolopendra pharmacopuncture has an ameliorating effect on depressive behavior, which is partially mediated through protection against glial loss in the hippocampus.

Resilience and Vulnerability to Pain and Inflammation in the Hippocampus

Increasing evidence demonstrates the importance of hippocampal neurogenesis, a fundamental mechanism of neuroplasticity associated with cognition and emotion, in correlation to neurodegenerative and psychiatric disorders. Neuropsychiatric disorders are often a result of chronic stress or pain followed by inflammation; all these conditions manifest cognitive deficits and impairments in neurogenesis. However, while some individuals are more susceptible to stress, others are able to adapt to new environments via mechanisms of resilience. In light of this emerging field and based on extensive research, the role of neurogenesis is summarized and presented as a potentially powerful therapeutic tool.

Efficacy of mirtazapine for the treatment of fibromyalgia without concomitant depression: a randomized, double-blind, placebo-controlled phase IIa study in Japan

Supplemental Digital Content is Available in the Text.

Twelve-week treatment with mirtazapine (30 mg/d) was effective and safe in controlling fibromyalgia pain in Japanese nonelderly adult patients without coexisting depression.

To evaluate the efficacy and safety of mirtazapine in Japanese patients with fibromyalgia (FM), a parallel-group, randomized, double-blind, placebo-controlled phase IIa study was conducted at 57 sites between November 2012 and February 2014. Patients aged 20 to 64 years who met the American College of Rheumatology 1990 diagnostic FM criteria and had stably high pain scores during a placebo run-in period were randomly assigned (1:1) by a computer-generated allocation sequence (block size 4) to receive mirtazapine orally (15 mg/d for 1 week and then 30 mg/d) or matching placebo for 12 weeks. The primary endpoint was change in mean numerical rating scale (NRS) pain score from baseline to endpoint (week 12 or early discontinuation). Of the 430 patients randomized (n = 215 each group), 422 (n = 211 each group) were analyzed for the primary endpoint. At the study endpoint, mirtazapine caused a significantly greater reduction in the mean NRS pain score compared with placebo (difference, 0.44; 95% confidence interval, −0.72 to −0.17; P = 0.0018). The reduction by mirtazapine remained significantly greater compared with placebo from week 6 onward. More patients treated with mirtazapine had their NRS pain score reduced by ≥30% from baseline (45.5% vs 30.8%). Mirtazapine also improved pain-related quality of life assessed by the Japanese version of the Fibromyalgia Impact Questionnaire and the Short-Form 36 Questionnaire. Adverse events were more common with mirtazapine than placebo (68.8% vs 56.7%), including somnolence (32.1% vs 7.4%), weight gain (17.7% vs 0.9%), and increased appetite (11.6% vs 3.3%). In conclusion, mirtazapine was an effective and safe treatment for Japanese patients with FM.

Pharmacokinetic profiles contribute to the differences in behavioral pharmacology of 071031B enantiomers as novel serotonin and norepinephrine reuptake inhibitors

Our previous study indicated that a chiral compound 071031B was a novel serotonin and noradrenaline reuptake inhibitor with superior antidepressant activity compared to duloxetine. The present study aimed to investigate chiral pharmacology differences of 071031B enantiomers, S-071031B and R-071031B, and disclose mechanisms underlying the behavioral differences based on target profiles and pharmacokinetic profiles. In vivo behavioral tests indicated that S-071031B was more potent than R-071031B in two depression models (the forced swimming test in mice and rats) and two pain models (the acetic acid-induced writhing and formalin tests in mice). In vitro assays revealed that both S-071031B and R-071031B showed high affinity for human serotonin transporters and norepinephrine transporters with equal potency, and showed consistently equipotent inhibitory effects on serotonin and norepinephrine uptake. Pharmacokinetic studies demonstrated that oral availability and hepatic metabolism, rather than pH stability, intestinal transport, and plasma binding, contributed to enantiomers' behavioral differences. Based on these findings, it is suggested that S-071031B is a more active enantiomer, and the differential pharmacokinetic profiles, but not target affinity, contribute to differences of S-071031B and R-071031B in behavioral pharmacology. Moreover, current PK-PD study may provide positive exploration for chiral antidepressants development.

Multi-biomarker investigation to assess toxicity induced by two antidepressants on Dreissena polymorpha

Antidepressants are one of the main pharmaceutical classes detected in the aquatic environment. Nevertheless, there is a dearth of information regarding their potential adverse effects on non-target organisms. Thus, the aim of this study was the evaluation of sub-lethal effects on the freshwater mussel Dreissena polymorpha of two antidepressants commonly found in the aquatic environment, namely Fluoxetine (FLX) and Citalopram (CT). D. polymorpha specimens were exposed to FLX and CT alone and to their mixture (MIX) at the environmental concentration of 500ng/L for 14days. We evaluated the sub-lethal effects in the mussel soft tissues by means of a biomarker suite: the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the activity of the phase II detoxifying enzyme glutathione-S-transferase (GST). The oxidative damage was evaluated by lipid peroxidation (LPO) and protein carbonylation (PCC), while genetic damage was tested on D. polymorpha hemocytes by Single Cell Gel Electrophoresis (SCGE) assay, DNA diffusion assay and micronucleus test (MN test). Finally, the functionality of the ABC transporter P-glycoprotein (P-gp) was measured in D. polymorpha gills. Our results highlight that CT, MIX and to a lesser extent FLX, caused a significant alteration of the oxidative status of bivalves, accompanied by a significant reduction of P-gp efflux activity. However, only FLX induced a slight, but significant, increase in apoptotic and necrotic cell frequencies. Considering the variability in biomarker response and to perform a toxicity comparison of tested molecules, we integrated each endpoint into the Biomarker Response Index (BRI). The data integration showed that 500ng/L of FLX, CT and their MIX have the same toxicity on bivalves.

Influence of tramadol on acute thermal and mechanical cutaneous nociception in dogs

OBJECTIVE

The aim of the study was to evaluate the influence of tramadol on acute nociception in dogs.

STUDY DESIGN

Experimental, blinded, randomized, crossover study.

ANIMALS

Six healthy laboratory Beagle dogs.

METHODS

Dogs received three treatments intravenously (IV): isotonic saline placebo (P), tramadol 1 mg kg^-1 (T1) and tramadol 4 mg kg^-1 (T4). Thermal thresholds were determined by ramped contact heat stimulation (0.6 °C second^-1) at the lateral thoracic wall. Mechanical thresholds (MT) were measured using a probe containing three blunted pins which were constantly advanced over the radial bone, using a rate of force increase of 0.8 N second^-1. Stimulation end points were defined responses (e.g. skin twitch, head turn, repositioning, vocalization) or pre-set cut-out values (55 °C, 20 N). Thresholds were determined before treatment and at predetermined time points up to 24 hours after treatment. At each measurement point, blood was collected for determination of O-desmethyltramadol concentrations. The degree of sedation and behavioural side effects were recorded. Data were analysed by one-way anova and two-way anova for repeated measurements.

RESULTS

Thermal nociception was not influenced by drug treatment. Mechanical nociception was significantly increased between P and T1 at 120 and 240 minutes, and between P and T4 at 30, 60, 240 and 420 minutes. T1 and T4 did not differ. O-desmethyltramadol (M1) maximum plasma concentrations (C_max) were 4.2±0.8 ng mL^-1 and 14.3±2.8 ng mL^-1 for T1 and T4, respectively. Times to reach maximum plasma concentrations (T_max) were 27.6±6.3 minutes for T1 and 32.1±7.8 minutes for T4. No sedation occurred. There were signs of nausea and mild to moderate salivation in both groups.

CONCLUSION AND CLINICAL RELEVANCE

Tramadol was metabolized marginally to O-desmethyltramadol and failed to produce clinically relevant acute antinociception. Therefore, the use of tramadol for acute nociceptive pain is questionable in dogs.

Bone mineral density is decreased in fibromyalgia syndrome: a systematic review and meta-analysis

Previous studies have shown that fibromyalgia syndrome (FMS) is associated with low level of physical activity and exercise, which may lead to an increased risk of osteoporosis. However, studies of bone mineral density (BMD) in fibromyalgia have shown conflicting results. Thus, we conducted a systematic review and meta-analysis to better characterize the association between FMS and BMD. A comprehensive search of the databases MEDLINE and EMBASE was performed from inception through May 2016. The inclusion criterion was the observational studies' assessment of the association between fibromyalgia and bone mineral density in adult subjects. Fibromyalgia was diagnosed in accordance with the American College of Rheumatology criteria for the diagnosis of fibromyalgia syndrome. BMD was measured at the lumbar spine and femoral neck by dual-energy X-ray absorptiometry. Pooled mean difference (MD) of BMD at each site and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method. The between-study heterogeneity of effect size was quantified using the Q statistic and I ². Data were extracted from four observational studies involving 680 subjects. At lumbar spine (L2-L4), BMD is significantly decreased in patients with FMS compared with controls with pooled MD of -0.02 (95% CI -0.03 to -0.01, P value = 0.003, I ² = 0%) (Fig. 1). At femoral neck, BMD is not significantly decreased in patients with FMS compared with controls with pooled MD of 0.01 (95% CI -0.02 to 0.01, P value = 0.23, I ² = 0%) (Fig. 2). In this meta-analysis, we observe that BMD at lumbar spine is decreased in FMS compared with normal individuals. Patients with FMS should be assessed for risk of osteoporosis. Fig. 1 Forest plot of bone mineral density at the lumbar spine, for patients with and without fibromyalgia syndrome. CI-confidence interval Fig. 2 Forest plot of bone mineral density at the femoral neck, for patients with and without fibromyalgia syndrome. CI-confidence interval.

Depressed Mood Differentially Mediates the Relationship between Pain Intensity and Pain Disability Depending on Pain Duration: A Moderated Mediation Analysis in Chronic Pain Patients

Research has shown that pain is associated with disability and that depressed mood mediates the relationship between pain and disability. The question of whether duration of pain moderates these effects was addressed in this cross-sectional study with 356 chronic pain patients. A simple mediation model replicated the notion that depressed mood explains a significant proportion of the relationship between pain and disability (in the study at hand: 12%). A moderated mediation model revealed that the indirect effect of pain on disability through depressed mood is moderated by pain duration: while depressed mood did not mediate the effect of pain on disability in chronic pain patients with shorter pain duration, depressed mood significantly mediated the effect pain exerts on disability in chronic pain patients with longer pain duration. Pain duration did not moderate the direct effect of pain on disability. Implications of these findings for the treatment of chronic pain might be that targeting depressed mood is especially relevant in chronic pain patients with longer pain duration to reduce the effect of pain on disability.

Pharmacologic basis for the use of selective norepinephrine reuptake inhibitors for the treatment of neuropathic pain conditions

Introduction

This article will review the pharmacologic and clinical evidence supporting the use of selective norepinephrine reuptake inhibitors, most notably atomoxetine, for the treatment of neuropathic pain states. Many medications initially marketed for psychiatric indications have gained widespread use for their analgesic properties after additional research.

Methods

In search of alternative treatments for neuropathic pain, current guidelines, published reviews, and primary literature, including both rodent and human trials, were reviewed.

Results and Discussion

The first group of medications to gain widespread use in pain management was the tricyclic antidepressants. As further research was completed and serotonin norepinephrine reuptake inhibitors began to be utilized for their analgesic properties, a growing body of evidence began to indicate that the analgesic properties of these medications were primarily due to the blockade of norepinephrine reuptake with serotonin playing only a minimal role.

Pharmacogenetics of analgesic drugs

• Individual variability in pain perception and differences in the efficacy of analgesic drugs are complex phenomena and are partly genetically predetermined.

• Analgesics act in various ways on the peripheral and central pain pathways and are regarded as one of the most valuable but equally dangerous groups of medications.

• While pharmacokinetic properties of drugs, metabolism in particular, have been scrutinised by genotype–phenotype correlation studies, the clinical significance of inherited variants in genes governing pharmacodynamics of analgesics remains largely unexplored (apart from the µ-opioid receptor).

• Lack of replication of the findings from one study to another makes meaningful personalised analgesic regime still a distant future.

• This narrative review will focus on findings related to pharmacogenetics of commonly used analgesic medications and highlight authors’ views on future clinical implications of pharmacogenetics in the context of pharmacological treatment of chronic pain.

Diagnosing and treating chronic musculoskeletal pain based on the underlying mechanism(s)

Until recently, most clinicians considered chronic pain to be typically due to ongoing peripheral nociceptive input (i.e., damage or inflammation) in the region of the body where the individual is experiencing pain. Clinicians are generally aware of a few types of pain (e.g., headache and phantom limb pain) where chronic pain is not due to such causes, but most do not realize there is not a single chronic pain state where any radiographic, surgical, or pathological description of peripheral nociceptive damage has been reproducibly shown to be related to the presence or severity of pain. The primary reason for this appears to be that both the peripheral and central nervous systems play a critical role in determining which nociceptive input being detected by sensory nerves in the peripheral tissues will lead to the perception of pain in humans. This manuscript reviews some of the latest findings regarding the neural processing of pain, with a special focus on how clinicians can use information gleaned from the history and physical examination to assess which mechanisms are most likely to be responsible for pain in a given individual, and tailors therapy appropriately. A critical construct is that, within any specific diagnostic category (e.g., fibromyalgia (FM), osteoarthritis (OA), and chronic low back pain (CLBP) are specifically reviewed), individual patients may have markedly different peripheral/nociceptive and neural contributions to their pain. Thus, just as low back pain has long been acknowledged to have multiple potential mechanisms, so also is this true of all chronic pain states, wherein some individuals will have pain primarily due to peripheral nociceptive input, whereas in others peripheral (e.g., peripheral sensitization) or central nervous system factors ("central sensitization" or "centralization" of pain via augmented pain processing in spinal and brain) may be playing an equally or even more prominent role in their pain and other symptoms.

Pharmacogenetics and analgesic effects of antidepressants in chronic pain management

Antidepressants are widely administered to chronic pain patients, but there is large interindividual variability in their efficacy and adverse effect rates that may be attributed to genetic factors. Studies have attempted to determine the impact of genetic polymorphisms in enzymes and transporters that are involved in antidepressant pharmacokinetics, for example, cytochrome P450 and P-gp. The impacts of genetic polymorphisms in the targets of antidepressants, such as the serotonin receptor or transporter, the noradrenaline transporter and the COMT and monoamine oxydase enzymes, have also been described. This manuscript discusses the current knowledge of the influence of genetic factors on the plasma concentrations, efficacy and adverse effects of the major antidepressants used in pain management.

The influence of μ-opioid and noradrenaline reuptake inhibition in the modulation of pain responsive neurones in the central amygdala by tapentadol in rats with neuropathy

Treatments for neuropathic pain are either not fully effective or have problematic side effects. Combinations of drugs are often used. Tapentadol is a newer molecule that produces analgesia in various pain models through two inhibitory mechanisms, namely central μ-opioid receptor (MOR) agonism and noradrenaline reuptake inhibition. These two components interact synergistically, resulting in levels of analgesia similar to opioid analgesics such as oxycodone and morphine, but with more tolerable side effects. The right central nucleus of the amygdala (CeA) is critical for the lateral spinal ascending pain pathway, regulates descending pain pathways and is key in the emotional-affective components of pain. Few studies have investigated the pharmacology of limbic brain areas in pain models. Here we determined the actions of systemic tapentadol on right CeA neurones of animals with neuropathy and which component of tapentadol contributes to its effect. Neuronal responses to multimodal peripheral stimulation of animals with spinal nerve ligation or sham surgery were recorded before and after two doses of tapentadol. After the higher dose of tapentadol either naloxone or yohimbine were administered. Systemic tapentadol resulted in dose-dependent decrease in right CeA neuronal activity only in neuropathy. Both naloxone and yohimbine reversed this effect to an extent that was modality selective.

The interactions of the components of tapentadol are not limited to the synergy between the MOR and α₂-adrenoceptors seen at spinal levels, but are seen at this supraspinal site where suppression of responses may relate to the ability of the drug to alter affective components of pain.

Does pain interfere with antidepressant depression treatment response and remission in patients with depression and pain? An evidence-based structured review

OBJECTIVE

The objective of this evidence-based structured review was to determine if there is consistent evidence that pain interferes with achieving antidepressant treatment response/remission of depression in patients with depression and pain.

METHODS

After exclusion criteria were applied, of 2,801 studies/reports, 17 studies addressed this question. They were sorted into the four hypotheses outlined herein after. The percentage of studies supporting/not supporting each hypothesis was calculated. The strength and consistency of the evidence for each hypothesis were rated according to the Agency for Health Care Research and Quality (AHRQ) guidelines.

RESULTS

For the first hypothesis (pretreatment pain levels will predict antidepressant depression response), nine out of 10 (90%) studies supported it. For the second hypothesis (treatment decreases in pain will be associated with antidepressant depression response), two out of two (100%) studies supported it. For the third hypothesis (pretreatment pain levels will predict antidepressant depression remission), six out of six (100%) studies supported it. For the fourth hypothesis (treatment decreases in pain will be associated with antidepressant depression remission), five out of five (100%) supported it. Utilizing these percentages and AHRQ guidelines, hypotheses 1, 3, and 4 received an A rating for consistency of studies in supporting them. A consistency rating for hypothesis 2 could not be generated because of too few studies in that group.

CONCLUSIONS

Consistent evidence was found that antidepressant treatment of depression in patients with depression and pain can be negatively impacted by pain for achieving depression response/remission. However, the overall number of studies supporting each hypothesis was small. In addition, several potential confounders of the results of this study were identified.

Uliginosin B, a natural phloroglucinol derivative, presents a multimediated antinociceptive effect in mice

Objective

Investigate the involvement of monoaminergic and glutamatergic systems on the antinociceptive and ataxic effects of uliginosin B, which we have already demonstrated to be a promising molecular scaffold to develop new analgesic drugs.

Methods

Uliginosin B was obtained from hexane extract of aerial parts of Hypericum polyanthemum by chromatographic methods. Uliginosin B antinociceptive and motor coordination effects were evaluated in mice by using hot-plate (15 and 90 mg/kg, i.p.) and rotarod (90 mg/kg, i.p.) tests, respectively. The mechanism of action was investigated through pretreatments with prazosin 1 mg/kg intraperitoneal (α1 receptor antagonist), yohimbine 5 mg/kg intraperitoneal (α2 receptor antagonist), pCPA 300 mg/kg intraperitoneal (serotonin synthesis inhibitor) and MK-801 0.25 mg/kg intraperitoneal (N-methyl-D-aspartic acid receptor antagonist).

Key findings

The antinociceptive effect of uliginosin B (15 and 90 mg/kg, i.p.) was reduced significantly by pCPA and MK-801. Prazosin and yohimbine improved the antinociceptive effect of the highest dose (90 mg/kg, i.p.) of uliginosin B only. The ataxic effect of uliginosin B (90 mg/kg, i.p.) was completely prevented by pretreatment with pCPA or MK-801, but it was unaffected by pretreatment with prazosin or yohimbine.

Conclusion

These data confirm the contribution of monoaminergic neurotransmission as well as provide the first evidence of glutamatergic neurotransmission contribution to the uliginosin B effects.

Are multiple physical symptoms a poor prognostic factor or just a marker of depression severity? Secondary analysis of the GenPod trial

BACKGROUND

Using data from the GenPod trial this study investigates: (i) if depressed individuals with multiple physical symptoms have a poorer response to antidepressants before and after adjustment for baseline Beck Depression Inventory II (BDI-II); and (ii) if reboxetine is more effective than citalopram in depression with multiple physical symptoms.

METHODS

Linear regression models were used to estimate differences in mean BDI-II score at 6 and 12 weeks.

RESULTS

Before adjusting for baseline BDI-II, the difference in mean BDI-II score between no and multiple physical symptoms was 4.5 (95% CI 1.87, 7.14) at 6 weeks, 4.51 (95% CI 1.60, 7.42) at 12 weeks. After adjustment for baseline BDI-II, there was no evidence of a difference in outcome according to physical symptoms with a difference in mean BDI-II of 2.17 (95% CI -0.39, 4.73) at 6 weeks and 2.43 (95% CI -0.46, 5.32) at 12 weeks. There was no evidence that reboxetine was more effective than citalopram in those with multiple physical symptoms at 6 (P=0.18) or 12 weeks (P=0.24).

LIMITATIONS

Differential non-adherence between treatment arms has the potential to bias estimates of treatment efficacy.

CONCLUSION

Multiple physical symptoms predict response to antidepressants, but not after adjustment for baseline depression severity. Physical symptoms could be a marker of severe depression rather than an independent prognostic factor and depression should be considered in patients with multiple physical symptoms. Treatment with reboxetine conferred no advantage over citalopram in those with physical symptoms, and it is less well tolerated.

Bone mass and vitamin D levels in women with a diagnosis of fibromyalgia

No differences in either bone mineral density or serum 25OHD levels have been found between 205 women with fibromyalgia (both pre- and postmenopausal) and their controls. However, a lack of the expected 25OHD summer rise was observed in patients.

INTRODUCTION

Contradictory data have been published regarding a possible association between fibromyalgia and osteoporosis or hypovitaminosis D. Most studies, however, have been performed in small size samples and have excluded postmenopausal women. We decided to study this association in a larger sample of fibromyalgia patients including both pre- and postmenopausal women.

METHODS

Two hundred five patients were recruited from a clinic specializing in fibromyalgia and 205 healthy controls were enrolled from the census of a Primary Care Center. Controls were matched with patients by age and the time of the year they were included in the study. Bone mineral density (BMD) was measured by DXA. Serum 25OHD, iPTH, P1NP, and CTX were also determined.

RESULTS

BMD was similar in both groups (lumbar spine, 0.971 ± 0.146 g/cm(2) in patients and 0.970 ± 0.132 g/cm(2) in controls; femoral neck, 0.780 ± 0.122 g/cm(2) and 0.785 ± 0.117 g/cm(2), respectively). 25OHD levels were also similar: 23.0 ± 9.5 ng/ml and 24.1 ± 9.6 ng/ml. However, while controls showed the usual summer rise in 25OHD, fibromyalgia patients did not. PTH did not show seasonal changes, but on average was higher in patients (51 pg/ml vs. 48 pg/ml; p = 0.034). P1NP or CTX were similar in both groups.

CONCLUSIONS

No differences in BMD were found between patients and controls. As for 25OHD, a lack of its expected summer rise was observed. It is doubtful whether this has any homeostatic consequence. We consider that the association reported in other studies is merely circumstantial, and not due to the intrinsic characteristics of these disorders.

Do minimally invasive procedures have a place in the treatment of chronic low back pain?

Chronic low back pain is the leading cause of disability in the industrialized world. Medical and surgical treatments remain costly despite limited efficacy. The field of 'interventional pain' has grown enormously and evidence-based practice guidelines are systematically developed. In this article, the vast, complex and contradictory literature regarding the treatment of chronic low back pain is reviewed. Interventional pain literature suggests that there is moderate evidence (small randomized, nonrandomized, single group or matched-case controlled studies) for medial branch neurotomy and limited evidence (nonexperimental one or more center studies) for intradiscal treatments in mechanical low back pain. There is moderate evidence for the use of transforaminal epidural steroid injections, lumbar percutaneous adhesiolysis and spinal endoscopy for painful lumbar radiculopathy, and spinal cord stimulation and intrathecal pumps mostly after spinal surgery. In reality, there is no gold standard for the treatment of chronic low back pain, but these results appear promising.

Correlation between gastrointestinal hormones and anxiety-depressive states in irritable bowel syndrome

The aim of this study was to investigate the mechanism(s) of action of gastrointestinal hormones in the pathogenesis of irritable bowel syndrome (IBS), and the correlation between gastrointestinal hormones and psychological factors. Patients with IBS were divided into IBS with normal emotional state ratings and IBS in anxiety-depressive states groups. The two groups were then subdivided into IBS-constipation predominant (IBS-C) and IBS-diarrhea predominant (IBS-D) groups. Non-IBS patients with normal depression and anxiety ratings were recruited as controls. The serum concentrations of somatostatin (SS) and vasoactive intestinal peptide (VIP) were measured by radioimmunoassay, and the expression of SS and VIP in the colonic mucosa was detected by immunohistochemistry and radioimmunoassay. The anxiety-depression scores of patients with IBS were significantly different from those of the control group (P<0.05). The expression levels of SS and VIP in the serum and colonic mucosa of the patients with IBS were higher compared with those of the control group. Furthermore, the expression level of SS in the IBS-C group demonstrated a significantly larger increase than that in the IBS-D group (P<0.05); however, there was no significant difference in the expression of VIP between the IBS-C and IBS-D groups (P>0.05). In addition, the expression levels of SS and VIP in the IBS groups with normal emotional state ratings were notably different from those in the IBS groups in anxiety-depressive states (P<0.05). Anxiety-depressive states may lead to changes in the secretion of SS and VIP, and subsequently to changes in gastrointestinal motility and function.

Antidepressant-like effects of 071031B, a novel serotonin and norepinephrine reuptake inhibitor

SNRIs (serotonin and norepinephrine reuptake inhibitors) have been proposed to exert increased therapeutic efficacy or be faster acting compared to commonly used antidepressants. In this study, we performed in vitro binding and uptake assays and in vivo behavioral tests to assess the pharmacological properties and antidepressant-like efficacy of the compound 071031B; we also performed cytotoxicity tests using HepG2 cells and SH-SY5Y cells to predict the toxicity of 071031B. In vitro, 071031B had high affinity for both serotonin transporters and norepinephrine transporters prepared from rat cortex tissue (Ki=2.68 and 1.09 nM, respectively) and recombinant cells (Ki=1.57 and 0.36 nM, respectively). Moreover, 071031B also potently inhibited the uptake of serotonin (5-HT) and norepinephrine (NE) into rat cortical synaptosomes (Ki=1.99 and 1.09 nM, respectively) and recombinant cells (Ki=3.23 and 0.79 nM, respectively). In vivo, acute administration of 071031B dose-dependently reduced the immobility time in the tail suspension test in mice and the forced swimming test in mice and rats with higher efficacy than duloxetine and showed no stimulatory effect on the locomotor activity. Chronic 071031B treatment (5 or 10mg/kg) significantly reversed depressive-like behaviors in chronically stressed rats, including reduced sucrose preference, decreased locomotor activity, and prolonged latency to begin eating. Furthermore, 071031B also exhibited lower cytotoxicity in HepG2 cells and SH-SY5Y cells in vitro than duloxetine. These findings suggest that 071031B is a novel, balanced serotonin and norepinephrine reuptake inhibitor, with more potent antidepressant effects and lower hepatotoxicity and neurotoxicity in vitro than duloxetine.

To what degree do shoulder outcome instruments reflect patients' psychologic distress?

BACKGROUND

Psychologic distress contributes to symptom severity in patients with several musculoskeletal disorders. While numerous shoulder outcome instruments are used it is unclear whether and to what degree psychologic distress contributes to the scores.

QUESTIONS/PURPOSES

We asked (1) to what degree shoulder outcome instruments reflect patients' psychologic distress, and (2) whether patients who are strongly affected by psychologic distress can be identified.

METHODS

We prospectively evaluated 119 patients with chronic shoulder pain caused by degenerative or inflammatory disorders using the Constant-Murley scale, Simple Shoulder Test (SST), and Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. To evaluate psychologic distress, we measured depression using the Center for Epidemiologic Studies-Depression (CES-D) scale and pain anxiety using the Pain Anxiety Symptom Scale (PASS). Demographic and clinical parameters, such as pain scores, ROM, and abduction strength, also were measured. We then assessed the relative contributions made by psychologic distress and other clinical parameters to the quantitative ratings of the three shoulder outcome instruments.

RESULTS

Quantitative ratings of shoulder outcome instruments correlated differently with psychologic distress. Constant-Murley scores did not correlate with psychologic measures, whereas SST scores correlated with PASS (r = 0.32) and DASH scores correlated with PASS and CES-D (r = 0.36 and r = 0.32). Psychologic distress contributed to worsening SST and DASH scores but not to Constant-Murley scores. DASH scores were more strongly influenced by pain anxiety and depression than the other two outcome instruments.

CONCLUSIONS

Shoulder outcome measures reflected different psychologic aspects of illness behavior, and the contributions made by psychologic distress to different shoulder outcome instruments apparently differed. Physicians should select and interpret the findings of shoulder outcome instruments properly by considering their psychologic implications.

LEVEL OF EVIDENCE

Level II, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

Fibromyalgia syndrome: etiology, pathogenesis, diagnosis, and treatment

Fibromyalgia syndrome is mainly characterized by pain, fatigue, and sleep disruption. The etiology of fibromyalgia is still unclear: if central sensitization is considered to be the main mechanism involved, then many other factors, genetic, immunological, and hormonal, may play an important role. The diagnosis is typically clinical (there are no laboratory abnormalities) and the physician must concentrate on pain and on its features. Additional symptoms (e.g., Raynaud's phenomenon, irritable bowel disease, and heat and cold intolerance) can be associated with this condition. A careful differential diagnosis is mandatory: fibromyalgia is not a diagnosis of exclusion. Since 1990, diagnosis has been principally based on the two major diagnostic criteria defined by the ACR. Recently, new criteria have been proposed. The main goals of the treatment are to alleviate pain, increase restorative sleep, and improve physical function. A multidisciplinary approach is optimal. While most nonsteroidal anti-inflammatory drugs and opioids have limited benefit, an important role is played by antidepressants and neuromodulating antiepileptics: currently duloxetine (NNT for a 30% pain reduction 7.2), milnacipran (NNT 19), and pregabalin (NNT 8.6) are the only drugs approved by the US Food and Drug Administration for the treatment of fibromyalgia. In addition, nonpharmacological treatments should be associated with drug therapy.

Effect of depressive symptoms on perceived disability in patients with chronic shoulder pain

BACKGROUND

Psychological distress may be an important determinant of perceived disability in patients with chronic musculoskeletal disorders. We evaluated the relationship between depressive symptoms and perceived disability in patients with chronic shoulder pain and quantified the contribution made by depression to perceived disability.

METHODS

In this prospective study, 109 patients with chronic shoulder pain caused by degenerative or inflammatory disorders were evaluated using the Disability of Arm, Shoulder and Hand (DASH) questionnaire and the Center for Epidemiologic Studies-Depression (CES-D) Scale to determine relationships between depressive symptoms and perceived disability in patients with chronic shoulder pain. In addition, pain scores were evaluated using a visual analog scale (VAS) during activity, and range of motion (ROM) and abduction strength (strength) measurements were measured. Multivariate analyses of variance and regression modeling were used to assess the relative contributions made by depressive symptoms (CES-D) and other clinical parameters to patient-perceived disability (DASH).

RESULTS

DASH scores were found to be moderately correlated (0.3 < r < 0.6) with ROM, strength, pain VAS and CES-D; DASH scores were more strongly correlated with CES-D scores than with pain VAS scores or range of motion (r = 0.58; p < 0.001, 0.37; p < 0.001, 0.32; p = 0.04 respectively). Multiple stepwise regression analyses revealed that gender, ROM, pain VAS and CES-D scores independently predicted DASH score and accounted for 43 % of the variance. CES-D score was found to be the strongest predictor of DASH score and accounted for 23 % of the variance.

CONCLUSIONS

Degrees of depressive symptoms were found to be significantly associated with higher symptom scores and greater disability in patients with chronic shoulder pain. Although a large proportion of perceived disability remains unexplained, perceived disability in patients with chronic shoulder pain was found to be strongly influenced by depressive symptoms.

TYPE OF STUDY/LEVEL OF EVIDENCE

Level 2, prospective cohort study, prognostic study.

Efficacy of duloxetine in patients with fibromyalgia: pooled analysis of 4 placebo-controlled clinical trials

OBJECTIVE

To investigate the efficacy of duloxetine in the treatment of pain and improvement in functional impairment and quality of life in patients with fibromyalgia from a pooled analysis of 4 placebo-controlled, double-blind, randomized trials.

METHOD

Patients were eligible for inclusion in the studies if they were at least 18 years of age, met criteria for fibromyalgia as defined by the American College of Rheumatology, and had specified minimum pain severity scores. Across all studies, 797 patients received duloxetine 60-120 mg/d and 535 patients received placebo. Pain was assessed by the Brief Pain Inventory (BPI) 24-hour average pain severity score; other efficacy measures included the Clinical Global Impressions-Severity of Illness scale (CGI-S), Patient Global Impressions-Improvement scale (PGI-I), 17-item Hamilton Depression Rating Scale (HDRS-17), Fibromyalgia Impact Questionnaire (FIQ) total score, BPI pain interference items, Sheehan Disability Scale (SDS), and Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) mental and physical components. Changes from baseline to endpoint (last observation carried forward) for most of the above efficacy measures were analyzed using an analysis-of-covariance model.

RESULTS

After 12 weeks of treatment, pain was significantly reduced in patients treated with duloxetine (P < .001) compared with placebo. In addition, duloxetine was superior to placebo in improving CGI-S (P < .001); PGI-I (P < .001); FIQ total (P < .001); HDRS-17 total (P = .003); SDS global functioning (P < .001), work/school (P = .018), and family life (P < .001); SF-36 mental (P < .001) and physical (P = .026) component; and BPI pain interference (P < .001) scores. Treatment-by-subgroup interactions were not significant for sex (P = .320), age (P = .362), or race (P = .180).

CONCLUSIONS

This pooled analysis provides evidence that 12 weeks of treatment with duloxetine 60-120 mg/d effectively improves fibromyalgia symptoms and may offer benefits beyond pain relief.

A systematic review of duloxetine for osteoarthritic pain: what is the number needed to treat, number needed to harm, and likelihood to be helped or harmed?

OBJECTIVE

To describe the efficacy, safety, and tolerability of duloxetine for the treatment of osteoarthritic pain.

DATA SOURCES

Systematic review of all published double-blind randomized controlled trials of duloxetine for osteoarthritic pain, supplemented by information in clinical trial registries, product labeling, and regulatory documents.

STUDY SELECTION

All available reports of studies were identified.

DATA EXTRACTION

Descriptions of the principal results and calculation of number needed to treat (NNT) for pain relief and other efficacy outcomes and number needed to harm (NNH) for relevant dichotomous adverse outcomes were extracted. Likelihood to be helped or harmed (LHH) was subsequently calculated.

DATA SYNTHESIS

US Food and Drug Administration approval for duloxetine for chronic pain associated with osteoarthritis (OA) was based on 2 randomized, double-blind, placebo-controlled clinical trials of 13 weeks' duration testing duloxetine 60 to 120 mg/d versus placebo. When study results were pooled, the proportion of patients experiencing clinically meaningful outcomes at study endpoint, such as a ≥ 30% or ≥ 50% reduction in pain scores, improvement in physical functioning, or subjective improvement, ranged from 42% to 67% for duloxetine, compared with 26% to 50% for placebo, depending on the specific measure; the NNT for these measures for duloxetine versus placebo was 7. The most commonly observed adverse reactions in duloxetine-treated patients were nausea (8.4% vs 2.0% for duloxetine and placebo, respectively), fatigue (6.7% vs 0.8%, respectively), and constipation (6.3% vs 0.8%, respectively), yielding NNH values of 16, 17, and 19, respectively. The LHH was consistently > 1.

CONCLUSIONS

Duloxetine appears efficacious and tolerable for the treatment of chronic pain associated with OA. The NNT and NNH can be used to quantify efficacy and tolerability outcomes and help place duloxetine into clinical perspective. Likelihood to be helped or harmed can illustrate to the clinician and patient the trade-offs between obtaining potential benefits versus harms. Head-to-head comparisons of duloxetine with other interventions for OA, as well as controlled trials of duloxetine in combination with other therapies, would be desirable.

Preliminary assessment of a neuropathic pain treatment and referral algorithm for patients with cancer

CONTEXT

The purpose of this case series study was to pilot test an evidence-based neuropathic pain (NP) treatment and referral algorithm for use by oncology nurses when managing cancer-related NP.

OBJECTIVES

The primary study objective was to assess patient-reported outcomes (pain severity, changes in activities of daily living, and satisfaction) resulting from algorithm use.

METHODS

Outpatients (n=20) with cancer-related NP scores ≥4 on a 0-10 numeric rating scale participated in the study. NP assessment, treatment, and referral to ancillary providers were guided by an evidence-based NP algorithm that was implemented by oncology nurse practitioners. Based on efficacy evidenced through randomized clinical trials published at the time of study implementation, the following drugs were included in the algorithm: lidocaine patch, gabapentin, oxycodone, tramadol, morphine, methadone, duloxetine, pregabalin, and nortriptyline. Recommendations for starting dose, dose escalation, drug combinations, treatment duration, and contraindications were included for first-tier drugs. Patient-reported outcomes (pain severity, functional capacity, and satisfaction) were assessed monthly over 12 weeks.

RESULTS

Average NP severity (P=0.001), general activity (P<0.001), mood (P=0.002), walking ability (P=0.01), ability to perform normal work (P=0.002), relationships (P=0.002), sleep (P=0.01), life enjoyment (P<0.001), and patient satisfaction (P=0.003) all improved by 12 weeks.

CONCLUSION

Evidence from this pilot study suggests that NP evidence-based treatment may result in improved symptoms, function, and patient satisfaction. A randomized controlled trial is needed to further assess algorithm efficacy.

Newer treatments for fibromyalgia syndrome

Fibromyalgia syndrome is a common chronic pain disorder of unknown etiology. The lack of understanding of the pathophysiology of fibromyalgia has made this condition frustrating for patients and clinicians alike. The most common symptoms of this disorder are chronic widespread pain, fatigue, sleep disturbances, difficulty with memory, and morning stiffness. Emerging evidence points towards augmented pain processing within the central nervous system (CNS) as having a primary role in the pathophysiology of this disorder. Currently the two drugs that are approved by the United States Food and Drug Administration (FDA) for the management of fibromyalgia are pregabalin and duloxetine. Newer data suggests that milnacipran, a dual norepinephrine and serotonin reuptake inhibitor, may be promising for the treatment of fibromyalgia. A double-blind, placebo-controlled trial of milnacipran in 125 fibromyalgia patients showed significant improvements relative to placebo. Milnacipran given either once or twice daily at doses up to 200 mg/day was generally well tolerated and yielded significant improvements relative to placebo on measures of pain, patient's global impression of change in their disease state, physical function, and fatigue. Future studies are needed to validate the efficacy of milnacipran in fibromyalgia.