Evidence-based data on pain relief with antidepressants

Psychological factors affecting response to antidepressant drugs in fibromyalgia

BACKGROUND

The use of antidepressant drugs in fibromyalgia is extensive despite small evidence of the real impact in the clinical practice setting. This study was aimed to evaluate the long-term efficiency of antidepressant treatment in fibromyalgia and the role of psychosocial factors in treatment response.

METHODS

A total of 102 consecutive patients with fibromyalgia from primary health care centers were studied with psychopathological and psychological assessment interviews and questionnaires. Sustained release venlafaxine was added to previous treatments in flexible doses from 150 to 300 mg daily for a 6-month period. Efficacy measures included the Clinical Global Impression (CGI) scale (patient and clinician versions) and the Fibromyalgia Impact Questionnaire (FIQ) score reduction.

RESULTS

At 6 months, 48% patients were considered responders to treatment (CGI change score 1 or 2) and 23.5% had a mild response. Of note, 57.8% had less fatigue and 31.4% had less pain. The proportion of responders was greater in the group with major depression (65%) than in those without depression (45%), but the difference did not reach statistical significance. However, the reduction of FIQ scores was significantly greater in depressed (21.1; IQR: 1.4-42.0) than in non-depressed patients (41.4; IQR: 23.6-52.6) (P<0.05). FIQ score reduction was significantly smaller in patients taking concomitant opiate treatment (P<0.01) and in patients seeking incapacitation (P<0.01).

CONCLUSION

Antidepressant treatment in fibromyalgia was effective in patients with and without major depression, but the functional response was greater in depressed patients. Treatment response to antidepressants might be significantly influenced by attitudinal and psychosocial factors of the disease.

Adjuvant analgesics in cancer pain: a review

Adjuvant analgesics (co-analgesics) are medications whose primary indication is the management of a medical condition with secondary effects of analgesia. Cancer pain is multifactorial and often involves inflammatory, nociceptive, and neuropathic pain subtypes. Adjuvant analgesics used in conjunction with opioids have been found to be beneficial in the management of many cancer pain syndromes; however, they are currently underutilized. Antidepressants, anticonvulsants, local anesthetics, topical agents, steroids, bisphosphonates, and calcitonin are all adjuvants which have been shown to be effective in the management of cancer pain syndromes. When utilizing analgesic adjuvants in the treatment of cancer pain, providers must take into account the particular side effect profile of the medication. Ideally, adjuvant analgesics will be initiated at lower dosages and escalated as tolerated until efficacy or adverse effects are encountered.

Association between comorbid depression and osteoarthritis symptom severity in patients with knee osteoarthritis

BACKGROUND

We sought to investigate the reported association between depression and severity of knee osteoarthritis symptoms stratified by radiographic severity of osteoarthritis and to quantify the contribution made by depression to symptom severity.

METHODS

Six hundred and sixty elderly Koreans (sixty-five years or older) were evaluated for radiographic severity of knee osteoarthritis on the basis of the Kellgren-Lawrence grading system and also for symptom severity on the basis of the Western Ontario and McMaster Universities Osteoarthritis Index scales. Patient interviews and a questionnaire that made use of a geriatric depression scale were conducted for the purpose of assessing depressive disorders. Regression analyses were performed to assess the relative contributions by radiographic severity and depression severity to Western Ontario and McMaster Universities Osteoarthritis Index scores and to explore any associations between radiographic severity and the presence of a depressive disorder with regard to the risk of symptomatic knee osteoarthritis. Symptomatic knee osteoarthritis was defined as a Western Ontario and McMaster Universities Osteoarthritis Index score of ≥39.

RESULTS

The presence of a depressive disorder was found to be associated with an increased risk of symptomatic knee osteoarthritis (odds ratio = 5.87 [95% confidence interval, 3.01 to 11.44]). However, the influence of the presence of a depressive disorder was limited to subjects with a radiographic severity of minimal to moderate (Kellgren-Lawrence grade 0 to 3). The presence of a depressive disorder was not associated with the risk of symptomatic knee osteoarthritis in subjects with severe osteoarthritis (Kellgren-Lawrence grade 4).

CONCLUSIONS

This study indicates that the assessment and management of coexisting depression should be integrated with the assessment and management of knee osteoarthritis, particularly when radiographic changes of osteoarthritis in the knee joint are not severe.

Evaluation of duloxetine for chronic pain conditions

Summary Duloxetine hydrochloride (duloxetine) is used as a nonopioid analgesic for the treatment of certain chronic pain conditions. It is a serotonin and norepinephrine reuptake inhibitor and has been approved in the USA for the management of both diabetic peripheral neuropathic pain and fibromyalgia. In addition, based on several studies demonstrating that duloxetine was efficacious in the management of chronic low back pain and chronic pain caused by osteoarthritis, duloxetine was approved for the management of chronic musculoskeletal pain. Effect sizes in studies of each of the aforementioned chronic pain conditions are comparable with other commonly used pain medications. Treatment-emergent adverse events are generally mild to moderate in severity, and tend to occur early and transiently.

Monoaminergic Antidepressants in the Relief of Pain: Potential Therapeutic Utility of Triple Reuptake Inhibitors (TRIs)

Over 75% of depressed patients suffer from painful symptoms predicting a greater severity and a less favorable outcome of depression. Imaging, anatomical and functional studies have demonstrated the existence of common brain structures, neuronal pathways and neurotransmitters in depression and pain. In particular, the ascending serotonergic and noradrenergic pathways originating from the raphe nuclei and the locus coeruleus; respectively, send projections to the limbic system. Such pathways control many of the psychological functions that are disturbed in depression and in the perception of pain. On the other hand, the descending pathways, from monoaminergic nuclei to the spinal cord, are specifically implicated in the inhibition of nociception providing rationale for the use of serotonin (5-HT) and/or norepinephrine (NE) reuptake inhibitors (SSRIs, NRIs, SNRIs), in the relief of pain. Compelling evidence suggests that dopamine (DA) is also involved in the pathophysiology and treatment of depression. Indeed, recent insights have demonstrated a central role for DA in analgesia through an action at both the spinal and suprasinal levels including brain regions such as the periaqueductal grey (PAG), the thalamus, the basal ganglia and the limbic system. In this context, dopaminergic antidepressants (i.e., containing dopaminergic activity), such as bupropion, nomifensine and more recently triple reuptake inhibitors (TRIs), might represent new promising therapeutic tools in the treatment of painful symptoms with depression. Nevertheless, whether the addition of the dopaminergic component produces more robust effects than single- or dual-acting agents, has yet to be demonstrated. This article reviews the main pathways regulating pain transmission in relation with the monoaminergic systems. It then focuses on the current knowledge regarding the in vivo pharmacological properties and mechanism of action of monoaminergic antidepressants including SSRIs, NRIs, SNRIs and TRIs. Finally, a synthesis of the preclinical studies supporting the efficacy of these antidepressants in analgesia is also addressed in order to highlight the relative contribution of 5-HT, NE and DA to nociception.

Synergistic interaction between the two mechanisms of action of tapentadol in analgesia

The novel centrally acting analgesic tapentadol [(-)-(1R,2R)-3-(3-dimethylamino-1-ethyl-2-methyl-propyl)-phenol hydrochloride] combines two mechanisms of action, μ-opioid receptor (MOR) agonism and noradrenaline reuptake inhibition (NRI), in a single molecule. Pharmacological antagonism studies have demonstrated that both mechanisms of action contribute to the analgesic effects of tapentadol. This study was designed to investigate the nature of the interaction of the two mechanisms. Dose-response curves were generated in rats for tapentadol alone or in combination with the opioid antagonist naloxone or the α(2)-adrenoceptor antagonist yohimbine. Two different pain models were used: 1) low-intensity tail-flick and 2) spinal nerve ligation. In each model, we obtained dose-effect relations to reveal the effect of tapentadol based on MOR agonism, NRI, and unblocked tapentadol. Receptor fractional occupation was determined from tapentadol's brain concentration and its dissociation constant for each binding site. Tapentadol produced dose-dependent analgesic effects in both pain models, and its dose-effect curves were shifted to the right by both antagonists, thereby providing data to distinguish between MOR agonism and NRI. Both isobolographic analysis of occupation-effect data and a theoretically equivalent methodology determining interactions from the effect scale demonstrated very pronounced synergistic interaction between the two mechanisms of action of tapentadol. This may explain why tapentadol is only 2- to 3-fold less potent than morphine across a variety of preclinical pain models despite its 50-fold lower affinity for the MOR. This is probably the first demonstration of a synergistic interaction between the occupied receptors for a single compound with two mechanisms of action.

Depression-like behavior and mechanical allodynia are reduced by bis selenide treatment in mice with chronic constriction injury: a comparison with fluoxetine, amitriptyline, and bupropion

RATIONALE

Neuropathic pain is associated with significant co-morbidities, including depression, which impact considerably on the overall patient experience. Pain co-morbidity symptoms are rarely assessed in animal models of neuropathic pain. Neuropathic pain is characterized by hyperexcitability within nociceptive pathways and remains difficult to treat with standard analgesics.

OBJECTIVES

The present study determined the effect of bis selenide and conventional antidepressants (fluoxetine, amitriptyline, and bupropion) on neuropathic pain using mechanical allodynic and on depressive-like behavior.

METHODS

Male mice were subjected to chronic constriction injury (CCI) or sham surgery and were assessed on day 14 after operation. Mice received oral treatment with bis selenide (1-5 mg/kg), fluoxetine, amitriptyline, or bupropion (10-30 mg/kg). The response frequency to mechanical allodynia in mice was measured with von Frey hairs. Mice were evaluated in the forced swimming test (FST) test for depression-like behavior.

RESULTS

The CCI procedure produced mechanical allodynia and increased depressive-like behavior in the FST. All of the drugs produced antiallodynic effects in CCI mice and produced antidepressant effects in control mice without altering locomotor activity. In CCI animals, however, only the amitriptyline and bis selenide treatments significantly reduced immobility in the FST.

CONCLUSION

These data demonstrate an important dissociation between the antiallodynic and antidepressant effects in mice when tested in a model of neuropathic pain. Depressive behavior in CCI mice was reversed by bis selenide and amitriptyline but not by the conventional antidepressants fluoxetine and buproprion. Bis selenide was more potent than the other drugs tested for antidepressant-like and antiallodynic effects in mice.

Comparative pain and mood effects in patients with comorbid fibromyalgia and major depressive disorder: secondary analyses of four pooled randomized controlled trials of duloxetine

The objective of this paper is to better understand the relationship of pain and mood in patients with fibromyalgia and comorbid major depressive disorder (MDD). Pooled data from 4 double-blind, placebo-controlled, randomized trials of duloxetine hydrochloride 60-120mg/day in patients with fibromyalgia were included (N=1332). Of these, 350 (26% [147 placebo, 203 duloxetine]) had comorbid MDD (per Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Text Revision criteria) and were included in these analyses. Primary measures included Brief Pain Inventory average pain; Hamilton Depression Rating Scale or Beck Depression Inventory. Logistic regression was used to evaluate the consistency of treatment effect across various subgroups. Path analysis was used to assess the effect of duloxetine on improvement in pain in the presence of improvement in mood and vice versa. Results indicated that 69% of improvement in pain was a direct effect of treatment, with improvement in mood accounting for 31% of pain response. In conclusion, consistent with our hypothesis, duloxetine produced a substantial direct effect on pain improvement and change in mood exerted a modest indirect effect on pain improvements in patients with fibromyalgia and MDD. Hence, both direct and indirect analgesic and antidepressant properties appear to be relevant for the treatment of these comorbid patients with duloxetine.

A comparison of change in the 0-10 numeric rating scale to a pain relief scale and global medication performance scale in a short-term clinical trial of breakthrough pain intensity

BACKGROUND

Pain intensity is commonly reported using a 0-10 Numeric Rating Scale in pain clinical trials. Analysis of the change on the Pain Intensity Numerical Rating Scale as a proportion has most consistently correlated with clinically important differences reported on the patient's global impression of change. The correlation of data from patients with breakthrough pain with a Pain Relief Scale and a different global outcome measures will extend our understanding of these measures.

METHODS

Data were obtained from the open titration phase of a multiple crossover, randomized, double-blind clinical trial comparing oral transmucosal fentanyl citrate with immediate-release oral morphine sulfate for the treatment of cancer-related breakthrough pain. Raw and percentage changes in the pain intensity scores from 1,307 episodes of pain in 134 oral transmucosal fentanyl citrate-naïve patients were correlated with the clinically relevant secondary outcomes of Pain Relief Verbal Response Scale and the global medication performance scale. The changes in raw and percentage change were assessed over time and compared with the ordinal Pain Relief Verbal Response Scale and Global Medication Performance Scale.

RESULTS

The P value of the interaction between the raw pain intensity difference was significant (P = 0.034) for four 15-min time periods but not for the percentage pain intensity difference score (P = 0.26). We found similar results in comparison with the ordinal Pain Relief Verbal Response Scale (P = 0.0048 and P = 0.36 respectively) and global medication performance categories (P = 0.048 and P = 0.45, respectively).

CONCLUSION

The change in pain intensity in breakthrough pain was more consistent over time and when compared with both the Pain Relief Verbal Response Scale and the Global Medication Performance Scale when the percentage change is used rather than raw pain intensity difference.

The pathophysiology, diagnosis and treatment of fibromyalgia

Research in fibromyalgia has increased understanding of the possible genetic and environmental factors that could be involved in the etiology of fibromyalgia. There is now substantial evidence for augmentation of central pain processing in fibromyalgia. Because the clinical presentation of fibromyalgia is heterogeneous, treatment recommendations must be individualized for each patient. The rapid growth of trials in fibromyalgia in recent years has resulted in new evidence-based approaches to pharmacological and nonpharmacological treatment.

Fibromyalgia: an overview

Fibromyalgia is the diagnosis given to individuals with chronic widespread musculoskeletal pain for which no alternative cause, such as tissue inflammation or damage, can be identified. Fibromyalgia is now believed to be, at least in part, a disorder of central pain processing that produces heightened responses to painful stimuli (hyperalgesia) and painful responses to nonpainful stimuli (allodynia). Aberrations in central pain processing may also be partly responsible for symptoms experienced in several chronic pain disorders that coaggregate with fibromyalgia, which is itself a product of genetic and environmental factors. Thus, aberrational central pain processing is implicated in irritable bowel syndrome, temporomandibular disorder, chronic low back pain, and certain other chronic pain disorders. Fibromyalgia and related disorders appear to reflect deficiencies in serotonergic and noradrenergic, but not opioidergic, transmission in the central nervous system. The heightened state of pain transmission may also be owing to increases in pronociceptive neurotransmitters such as glutamate and substance P. In some cases, psychological and behavioral factors are also in play. Although the overlapping symptomatology between fibromyalgia and related disorders may present diagnostic challenges, proper examination and observation can help clinicians make an accurate diagnosis. In recent years, the vastly improved understanding of the mechanism underlying fibromyalgia and the related spectrum of diseases has fostered rapid advances in the therapy of these chronic pain disorders by both pharmacologic and nonpharmacologic interventions.

Further strategies for treating fibromyalgia: the role of serotonin and norepinephrine reuptake inhibitors

Fibromyalgia and associated conditions such as irritable bowel syndrome and temporomandibular disorder involve dysfunctions in central sensitization and pain modulation. Central nervous system dysfunction may also contribute to other symptoms characteristic of fibromyalgia, such as fatigue and sleep disturbance. Two key neurotransmitters in the pain modulation pathway are serotonin and norepinephrine. Preclinical studies using animal models of chronic pain have shown that pharmacologic agents that combine serotonergic and noradrenergic reuptake inhibition, thus augmenting the function of these neurotransmitters, have stronger analgesic effects than agents that inhibit reuptake of either neurotransmitter alone. Although tricyclic antidepressants (TCAs) inhibit reuptake of both serotonin and norepinephrine and have shown efficacy for the treatment of fibromyalgia, long-term use of these drugs is limited owing to poor tolerability. Unlike TCAs, the newer dual reuptake inhibitors of serotonin and norepinephrine, such as the drugs approved by the US Food and Drug Administration (FDA) for fibromyalgia, milnacipran and duloxetine, do not possess significant affinity for other neurotransmitter systems, resulting in diminished side effects and enhanced tolerability. Both duloxetine and milnacipran have shown efficacy in clinical trials by improving pain and other symptoms associated with fibromyalgia. Both compounds inhibit the serotonin and norepinephrine transporters; however, there is a difference in their affinities and selectivity for these transporters. Although duloxetine has affinity for both receptors, it is somewhat more selective for the serotonin transporter. In contrast, milnacipran is somewhat more selective for norepinephrine than serotonin reuptake inhibition. Pharmacologic agents that specifically target serotonin and norepinephrine reuptake may prove to be valuable tools in the treatment of fibromyalgia.

Advances in the management of fibromyalgia

In summary, new FDA approvals offer options for the treatment of FM. CNS targets have proven to be effective in the treatment of FM. However, treatment must be individualized and the integration of various pharmacologic and nonpharmacologic treatments may be the best approach.

Mirtazapine versus venlafaxine for the treatment of somatic symptoms associated with major depressive disorder: a randomized, open-labeled trial

Somatic symptoms are often important in the treatment of major depressive disorder (MDD). The aim of this open-labeled trial was to examine the efficacy of mirtazapine for the treatment of MDD with clinically significant somatic symptoms, as compared with venlafaxine. A total of 126 patients with MDD (score >/=18 on the Hamilton Rating Scale for Depression-17) were included in both the intent-to-treat (n=73 in the mirtazapine group and n=53 in the venlafaxine group) and completer analysis (n=51 and n=37, respectively). After treatment, both treatment groups showed similar improvements in depressive symptoms. Repeated measures analysis of variance for the intent-to-treat population revealed that there were no significant differences in mean change of the Symptom Check List-90-Revised (SCL-90-R) somatization subscores between the two groups. For completers, there was a significant timextreatment interaction in the SCL-90-R somatization subscores, but the differences between the two groups at endpoint did not reach statistical significance in post-hoc analysis. In conclusion, this study suggests that overall efficacies of mirtazapine and venlafaxine are similar for the treatment of overall symptoms in MDD, and both drugs may be useful for the treatment of somatic symptoms in MDD patients.

Understanding fibromyalgia: lessons from the broader pain research community

Fibromyalgia (FM) is a chronic pain condition marked by centrally mediated augmentation of pain and sensory processes. Skepticism has marked the history of this condition, but more recent study has identified neurobiological underpinnings supporting many of the symptoms associated with this condition. Early research in FM had unprecedented latitude within the rheumatology community to borrow heavily from theory and methods being applied in chronic pain research more generally. These insights facilitated rapid advances in FM research, not the least of which was the abandonment of a peripheral focus in favor of studying central mechanisms associated with central augmentation. Currently, rapid-paced discovery is taking place in FM genetics, patient assessment, new therapeutic targets, and novel methods of treatment delivery. Such insights are not likely to be limited in application just to FM and could have relevance to the broader field of pain research as well.

PERSPECTIVE

This manuscript reviews the history of FM and its diagnosis, evidence supporting central augmentation of pain in FM, potential mechanisms of central augmentation, current approaches to integrated care of FM, and areas of active collaboration between FM research and other chronic pain conditions.

Antidepressant use in painful rheumatic conditions

This article reviews the pharmacologic and clinical evidence supporting the use of antidepressant drugs for treating painful rheumatologic conditions. Clinical studies have shown that tricyclic antidepressants, even at low doses, have analgesic effects in rheumatologic conditions equivalent to those of serotonin and noradrenalin reuptake inhibitors, but are less well tolerated. Selective serotonin reuptake inhibitors may also have analgesic effects, but higher doses are required to achieve analgesia in conditions such as fibromyalgia and low back pain. Antidepressant drugs may be useful in painful rheumatologic conditions, but in some studies the analgesic effects of antidepressants may be associated with functional impairment, sleep disorders, and fatigue. Further studies are required to determine antidepressants' analgesic mechanism of action and the specific role they should play in the management of chronic painful rheumatologic conditions.

Depression and osteoarthritis

Depression is significant among patients with arthritis and musculoskeletal illnesses. However, the impact of depression on osteoarthritis has not been extensively studied. This article highlights the close links between these 2 prevalent chronic conditions, and the associated individual and societal burden. Results from a large clinical trial of depressed older patients with arthritis showed that a focused, collaborative depression care intervention not only decreased depression but also improved arthritis-associated outcomes, such as pain severity and arthritis-related limitations in daily activities. Relative to patients given usual care, patients receiving intervention also reported better health status and higher quality of life. Analyses of the depression interventions uncovered a reciprocal interrelation between depression and pain. Higher severity of either depression or pain decreased the benefits of systematic depression treatment and was associated with worse pain and depression outcomes. Current approaches to management of depression and arthritis do not reflect readily-available evidence-based treatment. A pilot study using a combined approach to address both depression and pain problems among elderly patients with depression and osteoarthritis suggested that benefits for depression, pain, and functional outcomes are strengthened by providing both pain and depression care management. An integrated depression and pain program using evidenced-based pharmacologic and nonpharmacologic treatments is needed to achieve optimal depression and pain outcomes. Currently, a randomized trial is under way to evaluate effectiveness of a combined pain and depression intervention using pharmacologic and nonpharmacologic therapies. Key intervention components in these 2 innovative and integrated depression and pain programs can guide clinicians to treat both depression and pain with more focus and intensity.

The relationship between antidepressant and analgesic responses: findings from six placebo-controlled trials assessing the efficacy of duloxetine in patients with major depressive disorder

OBJECTIVE

Debate continues regarding whether onset of analgesia is faster than antidepressant effect in antidepressants with both properties. Duloxetine hydrochloride (from here on referred to as duloxetine) is effective in both major depressive disorder and diabetic peripheral neuropathic pain. This post-hoc analysis of six placebo-controlled duloxetine trials in patients with major depressive disorder was designed to compare onset of antidepressant activity to pain relief.

RESEARCH DESIGN AND METHODS

Duloxetine was administered at 40-120 mg/day versus placebo for up to 9 weeks in outpatient clinic settings. The primary depression measure was the HAMD(17) and pain severity was measured using visual analog scale (VAS) measuring overall pain, headache, back and shoulder pain, and pain while awake. The time course of improvement was profiled using repeated measures modeling and Kaplan-Meier product limit estimation.

RESULTS

In all but one case, significant reductions in HAMD(17) and VAS scores were seen within 2 weeks of treatment. Median time to VAS response was consistently shorter across all VAS measures than that to HAMD(17) response in both placebo- and duloxetine-treated patients with at least modest levels of pain at study entry. Regression analyses consistently demonstrated little association between analgesic and antidepressant responses. Limitations of these findings include that the studies used in these analyses did not require the patients to enroll with any specific level of pain. Moreover, the type of pain exhibiting at presentation was not routinely identified; therefore, the impact of different pain types on these findings is unknown.

CONCLUSIONS

Duloxetine's analgesic effect is independent of the drug's antidepressant effect. Additionally, faster onset of the analgesic effect appears to be a population-specific phenomenon that is unmodified in the presence of active agents.

Is there any evidence to support the use of anti-depressants in painful rheumatological conditions? Systematic review of pharmacological and clinical studies

The aim of this study was to review the evidence supporting the use of anti-depressants in painful rheumatological conditions. A systematic review of papers published between 1966 and 2007, in five European languages, on anti-depressants in rheumatological conditions was performed. Papers were scored using Jadad method and analgesic ES was calculated. We selected 78 clinical studies and 12 meta-analyses, from 140 papers. The strongest evidence of an analgesic effect of anti-depressants has been obtained for fibromyalgia. A weak analgesic effect is observed for chronic low back pain, with an efficacy level close to that of analgesics. In RA and AS, there is no analgesic effect of anti-depressants, but these drugs may help to manage fatigue and sleep disorders. There is no clear evidence of an analgesic effect inOA, but studies have poor methodological quality. Analgesic effects of anti-depressants are independent of their anti-depressant effects. Tricyclic anti-depressants (TCAs), even at low doses, have analgesic effects equivalent to those of serotonin and noradrenalin reuptake inhibitors (SNRIs), but are less well tolerated. Selective serotonin reuptake inhibitors (SSRIs) have modest analgesic effects, but higher doses are required to achieve analgesia. Anti-depressant drugs, particularly TCAs and SNRIs, have analgesic effects in chronic rheumatic painful states in which analgesics and NSAIDs are not very efficient, such as fibromyalgia and chronic low back pain. In inflammatory rheumatic diseases, anti-depressants may be useful for managing fatigue and sleep disorders. Further studies are required to compare anti-depressants with other analgesics in the management of chronic painful rheumatological conditions.

Fibromyalgia: harmonizing science with clinical practice considerations

This review summarizes the present and emerging knowledge base on the pathophysiology, diagnosis, and management of fibromyalgia.

EPIDEMIOLOGY

Fibromyalgia is the most common chronic pain syndrome encountered in general medicine and rheumatology. Historically, contemporary concepts of fibromyalgia have evolved in terms of its clinical description and parallel advances in the understanding of its pathophysiology.

PATHOPHYSIOLOGY

A generally accepted paradigm postulates that fibromyalgia is the clinical expression of a rheumatologic disorder in which the associated pain is driven primarily by central sensitization and possibly through changes in several neuronal systems but not necessarily reliant on peripheral processes.

MANAGEMENT

Several agents, including serotonin-norepinephrine reuptake inhibitors (ie, duloxetine and milnacipran), opioids (ie, tramadol), and the alpha2-delta ligand pregabalin, which recently received U.S. regulatory approval for the treatment of fibromyalgia, have been evaluated in clinical trials, demonstrating benefit in terms of pain reduction and improvement in core symptoms (ie, fatigue and sleep disturbance). The European League Against Rheumatism has developed updated guidelines for the management of fibromyalgia.

Painful physical symptoms in depression: a clinical challenge

Painful physical symptoms are common elements within mood disorders and provide a therapeutic challenge when such patients attribute their pain to causes other than the mood disorder. These somatic presentations may lead to under-diagnosis and inappropriate treatment of patients with mood disorders. Antidepressant agents that inhibit both serotonin and norepinephrine reuptake effectively remit mood disorders, thereby providing relief of painful physical symptoms often associated with these disorders. They may also provide analgesia for neuropathic pain, such as that caused by diabetic neuropathy, which are associated with mood disorders. Newer generation dual acting antidepressants such as duloxetine and venlafaxine offer a well-tolerated and safe alternative to tricyclics. Concurrent with medication and management, the physician must educate the patient about the nature of both depressed mood and painful physical states that are augmented by and inherent in the depressive disorders. This mini review addresses the problems inherent to the treatment of painful physical symptoms in depression.

Duloxetine and Other Antidepressants in the Treatment of Patients with Fibromyalgia

OBJECTIVE

To review the use of duloxetine, a new selective serotonin and norepinephrine reuptake inhibitor (SNRI), and other antidepressants in the treatment of patients with fibromyalgia.

DESIGN

Two randomized, placebo-controlled, double-blind, parallel-group, 12-week trials of duloxetine in the treatment of fibromyalgia were reviewed. Other published, randomized, placebo-controlled, double-blind trials, and meta-analyses of antidepressant treatment of fibromyalgia were identified by a PubMed search that was augmented by reference cross-check.

RESULTS

Duloxetine has been shown to be an effective and safe treatment for many of the symptoms associated with fibromyalgia, particularly for women. Other selective SNRIs also show promise in the treatment of fibromyalgia. Until recently, tricyclic agents that have serotonin and norepinephrine reuptake inhibitory activity had been the most commonly studied group of antidepressants, and they are effective in treating pain and other symptoms associated with fibromyalgia, although their use may be limited by safety and tolerability concerns. There are few randomized, controlled studies of selective serotonin reuptake inhibitors in fibromyalgia, and the results have been mixed.

CONCLUSIONS

Antidepressants play an important role in the treatment of patients with fibromyalgia. Agents with dual effects on serotonin and norepinephrine appear to have more consistent benefits than selective serotonin antidepressants for the treatment of persistent pain associated with fibromyalgia.

Chronic pain management in spine disorders

Chronic nonmalignant pain is less a symptom of a disease than a disease in itself. Accordingly, successful treatments rely less on identifying underlying pathology than on treating neural causes of pain amplification, psychologic causes of disability, and the sequelae of deconditioning and psychiatric illness. The outcome, when such treatment is provided, is remarkably favorable.

New developments in the use of tricyclic antidepressants for the management of pain

In recent years, tricyclic antidepressant drugs have experienced a resurgence in their use as valuable pharmacological tools in the treatment of pain. Along with the evolution in our understanding of their analgesic mechanisms of action, there have been concurrent breakthroughs regarding their indications for use and modes of administration. This review focuses on recent advances in our understanding of how antidepressant drugs exert their antinociceptive effects, and new developments regarding their clinical application.

Medication use in a female orofacial pain population

OBJECTIVE

This study compared, both quantitatively and qualitatively, the self-reported medication usage between an adult female orofacial pain population and a comparison group.

STUDY DESIGN

Eighty-seven subjects from both an orofacial pain center (OPC) and undergraduate dental clinic (UDC) completed a standardized medical history questionnaire. Both groups had a similar distribution with regard to age. The number of medications and medication categories were compared between the two groups. Statistical analysis used the Student t-test, Fisher's exact tests, Pearson's chi2 tests, and calculated odds ratios.

RESULTS

The number of pain and non-pain medications, and the number of medication categories endorsed by OPC subjects was significantly higher compared with the UDC group.

CONCLUSION

Adult female orofacial pain subjects report greater overall and higher rate of medication use, which was not limited to only the analgesic/narcotic categories, than the comparison group.

Duloxetine treatment of pediatric chronic pain and co-morbid major depressive disorder

In the United States, the novel compound duloxetine has been approved for the treatment of major depressive disorder (MDD) and diabetic peripheral neuropathic pain in the adult population. There are currently no published data on the use of duloxetine in children and adolescents. This report describes the successful treatment of 2 adolescent females with chronic pain and co-morbid MDD. Both patients required admission to a tertiary-care pediatric hospital due to the chronicity, severity, and treatment resistance of their pain syndromes. In both cases, duloxetine provided rapid improvement in the experience of pain, as well as mood symptoms, at minimum dosages. Pain symptom reduction and restoration of a euthymic state was maintained at 4- and 3-month follow-up visits, respectively, with minimal to no adverse effects being reported. These cases present preliminary evidence of promising uses for duloxetine in the pediatric population.

Effects of Analgesic or Antidepressant Drugs on Pain- or Stress-Evoked Hippocampal and Spinal Neurokinin-1 Receptor and Brain-Derived Neurotrophic Factor Gene Expression in the Rat

Clinical studies show that people suffering from chronic pain are often also burdened by depression. Antidepressants are used to treat some types of chronic pain; however, little is known about their mechanisms of action. This study addressed the effects of a nonsteroidal anti-inflammatory drug and a tricyclic antidepressant drug on pain- and stress-evoked gene expression in the rat spinal cord dorsal horn and hippocampus. Rats were pretreated with either indomethacin or imipramine and then challenged with either intraplantar complete Freund's adjuvant or a bout of immobilization stress. Results showed that indomethacin significantly reduced nociception-related peripheral edema, hyperalgesia, and reversed the pain-evoked up-regulation of neurokinin (NK)-1 receptor and brain-derived neurotrophic factor (BDNF) gene expression in the spinal cord to levels not statistically different from controls. However, indomethacin did not protect against significant pain-induced down-regulation of these genes in the hippocampus by approximately 50%, suggesting that although analgesic drug treatment reduces nociceptive sensory activation in the spinal cord, it is insufficient to prevent the impact of pain on the hippocampus. Conversely, although imipramine did not provide significant behavioral analgesia, it significantly blocked both pain- and stress-evoked alterations in hippocampal and spinal NK-1 and BDNF gene expression. Thus, these results show that application of either analgesic or antidepressant drugs alone does not fully protect against both the behavioral and molecular effects of persistent pain on both "sensory" and "affective" processing within the central nervous system.

Therapy Insight: fibromyalgia—a different type of pain needing a different type of treatment

In the past decade, we have made tremendous progress in our understanding of fibromyalgia, which is now recognized as one of many 'central' pain syndromes that are common in the general population. Specific genes that might confer an increased risk of developing fibromyalgia syndrome are beginning to be identified and the environment (in this case exposure to stressors) might also have a significant effect on triggering the expression of symptoms. After developing the syndrome, the hallmark aberration noted in individuals with fibromyalgia is augmented central pain processing. Insights from research suggest that fibromyalgia and related syndromes require a multimodal management program that is different from the standard used to treat peripheral pain (i.e. acute or inflammatory pain). Instead of the nonsteroidal anti-inflammatory drugs and opioids commonly used in the treatment of peripheral pain, the recommended drugs for central pain conditions are neuroactive compounds that downregulate sensory processing. The most efficacious compounds that are currently available include the tricyclic drugs and mixed reuptake inhibitors that simultaneously increase serotonin and norepinephrine concentrations in the central nervous system. Other compounds that increase levels of single monoamines (serotonin, norepinephrine or dopamine), and anticonvulsants also show efficacy in this condition. In addition to these pharmacologic therapies, which are useful in improving symptoms, nonpharmacologic therapies such as exercise and cognitive behavioral therapy are useful treatments for restoring function to an individual with fibromyalgia.

Sleep quality and the role of sleep medications for veterans with chronic pain

OBJECTIVE

The purpose of this study was to investigate the nature of sleep problems in veterans presenting to a pain clinic, factors that predict likelihood of being prescribed a sleep medication, types of medications prescribed, and the relationships between sleep medication use and sleep quality, pain, and depression.

DESIGN/SETTING/PATIENTS

Participants were 201 consecutive patients referred to a Veterans Affairs outpatient pain clinic. They were administered the Pittsburgh Sleep Quality Index, Multidimensional Pain Inventory, and Beck Depression Inventory at intake and 2-month follow-up. Sleep and opioid medication prescriptions were also monitored.

RESULTS

Pain severity did not predict global sleep quality; global sleep quality was not predictive of pain severity. Greater depression predicted both more severe pain and more sleep impairment. Having previously been prescribed such medications was the only significant predictor of being prescribed a sleep medication at the time of the 2-month assessment. For the 45% of participants on sleep medications, these medications were not associated with any significant change in pain factors or depression. However, sleep medication use was associated with worse global sleep quality, sleep duration, and sleep efficiency. Opioid prescription was not a significant predictor of sleep factors, pain-related variables, or depression symptoms.

DISCUSSION

Results suggest depression may contribute more significantly to sleep problems than pain-related variables in this population. The data suggest the need for controlled, prospective studies of sleep medication to further investigate the impact of sleep medications on sleep components in patients with chronic pain.

Management of psychiatric comorbidity in fibromyalgia

Fibromyalgia is a chronic musculoskeletal pain condition of unknown etiology that predominantly affects women. Lifetime mood and anxiety disorders are common in patients with fibromyalgia and affect the course and severity of fibromyalgia. Recent fibromyalgia clinical trials have included clinical assessments to identify comorbid psychiatric disorders and determine the impact of comorbidity on treatment response. Options for the treatment of fibromyalgia patients with comorbid major depressive disorder or anxiety disorders include antidepressants with dual effects on serotonin and norepinephrine (eg, venlafaxine, duloxetine), which reduce pain in patients with fibromyalgia and have antidepressant and anxiolytic activity. Other possible treatments for anxiety or sleep disturbances associated with fibromyalgia include the alpha-2-delta ligands (eg, pregabalin, gabapentin) that reduce pain in fibromyalgia patients, have anxiolytic effects, and enhance slow-wave sleep. Antidepressants or alpha-2-delta ligands should be combined with established mood stabilizers in patients with comorbid fibromyalgia and bipolar disorder. There is also evidence to support exercise and cognitive-behavioral therapy in the treatment of fibromyalgia and mood or anxiety disorders. Many patients would likely benefit from combinations of pharmacologic and nonpharmacologic treatments.

Spinal stenosis: surgical versus nonsurgical treatment

Lumbar spinal stenosis is being diagnosed increasingly in older people as advanced imaging studies become more widely available and clinicians become more familiar with the presentation of this common condition. For symptomatic patients, the goal of treatment is pain relief and improved function, but there is little empiric evidence to support many of the common interventions used. The relative risks and benefits of various surgical and nonsurgical treatments are poorly understood, and the result has been wide variations in the evaluation and treatment of spinal stenosis across geographic regions. Current practice recommendations are based on expert opinion that incorporates available evidence into existing clinical and biologic paradigms. For most individuals, initial treatment should focus on patient education, medications to control pain, and exercise and physical treatments to regain or maintain activities of daily living. Surgical treatment most commonly is considered in patients not improving with nonsurgical care. Decompressive laminectomy is the standard surgical procedure for patients with spinal stenosis. The addition of fusion with or without instrumentation is considered when spinal stenosis is accompanied by degenerative spondylolisthesis or related to concerns about instability. We review the available evidence for nonsurgical and surgical interventions, and highlight comparative results wherever applicable.

LEVEL OF EVIDENCE

Level V (expert opinion). See the Guidelines for Authors for a complete description of levels of evidence.

Diagnosticando e tratando depressão no paciente com doença clínica

Diagnosticar depressão em um doente clínico é uma tarefa difícil por vários motivos. Muito embora tristeza e humor depressivo possam indicar síndrome depressiva subjacente, eles também podem fazer parte da adaptação normal a uma doença que ameace a vida. Os sintomas somáticos e vegetativos incluídos nos critérios diagnósticos das classificações atuais não são específicos e podem de fato ser atribuíveis à hospitalização, aos tratamentos ou à própria doença clínica. Tratar a depressão no paciente clínico é também difícil devido à preocupação com a interação de drogas, assim como questões de eficácia e segurança nesse grupo. Nesta conferência clínica os autores discutem questões como que diagnósticos podem ser feitos em pacientes clínicos com sintomas depressivos; prevalência de depressão em diferentes ambientes; mecanismos de co-morbidade (fatores fisiológicos e comportamentais) que relacionam a depressão às doenças clínicas e o manuseio da depressão nesse grupo.