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Biomedical subjects

Robert H Dworkin

Publications and source records attributed to Robert H Dworkin.

At least 19 recordsLinked to original sources
PubMed2007

Recommendations for the management of herpes zoster.

The objective of this article is to provide evidence-based recommendations for the management of patients with herpes zoster (HZ) that take into account clinical efficacy, adverse effects, impact on quality of life, and costs of treatment. Systematic literature reviews, published randomized clinical trials, existing guidelines, and the authors' clinical and research experience relevant to the management of patients with HZ were reviewed at a consensus meeting. The results of controlled trials and the clinical experience of the authors support the use of acyclovir, brivudin (where available), famciclovir, and valacyclovir as first-line antiviral therapy for the treatment of patients with HZ. Specific recommendations for the use of these medications are provided. In addition, suggestions are made for treatments that, when used in combination with antiviral therapy, may further reduce pain and other complications of HZ.

2-Aminopurine↗
PubMed2007

An interdisciplinary expert consensus statement on assessment of pain in older persons.

This paper represents an expert-based consensus statement on pain assessment among older adults. It is intended to provide recommendations that will be useful for both researchers and clinicians. Contributors were identified based on literature prominence and with the aim of achieving a broad representation of disciplines. Recommendations are provided regarding the physical examination and the assessment of pain using self-report and observational methods (suitable for seniors with dementia). In addition, recommendations are provided regarding the assessment of the physical and emotional functioning of older adults experiencing pain. The literature underlying the consensus recommendations is reviewed. Multiple revisions led to final reviews of 2 complete drafts before consensus was reached.

Age Factors↗
PubMed2006

Symptom profiles differ in patients with neuropathic versus non-neuropathic pain.

UNLABELLED: The distinction between neuropathic and non-neuropathic pain reflects partially distinct mechanisms and patterns of treatment response. It was therefore hypothesized that patients with neuropathic and non-neuropathic pain have different profiles of symptoms and signs. To test this hypothesis, pain intensity, unpleasantness, quality, and spatial characteristics were examined in 618 patients with 1 of 3 peripheral neuropathic pain conditions (painful diabetic peripheral neuropathy, painful idiopathic sensory polyneuropathy, or postherpetic neuralgia), osteoarthritis pain, or low back pain. These assessments were conducted before treatment had begun in clinical trials of lidocaine patch 5% administered alone or with stable dosages of other analgesics. Patients with osteoarthritis pain and low back pain did not differ in their profile of pain quality and spatial characteristics and were combined to form a group of patients with non-neuropathic pain. In univariate analyses, patients with peripheral neuropathic pain reported significantly more intense hot, cold, sensitive, itchy, and surface pain and significantly less intense dull and deep pain than patients with non-neuropathic pain. In a multivariate analysis, the overall pattern of pain quality and spatial characteristics differed significantly between patients with neuropathic and non-neuropathic pain. In addition, specific pain quality and spatial characteristics improved the discrimination of patients with neuropathic and non-neuropathic pain in a logistic regression model that adjusted for demographic covariates and overall pain intensity and unpleasantness. PERSPECTIVE: The results indicate that the distinction between neuropathic and non-neuropathic pain is reflected in different profiles of pain quality and spatial characteristics and suggest that the assessment of patterns of pain symptoms might contribute to the identification of distinct pathophysiologic mechanisms and the development of mechanism-based treatment approaches.

Administration, Topical↗
PubMed2006

Skin biopsy and quantitative sensory testing do not predict response to lidocaine patch in painful neuropathies.

Predictors of response to neuropathic pain treatment in patients with painful distal sensory neuropathies are lacking. The 5% lidocaine patch is believed to exert its effects on neuropathic pain via a local stabilizing effect on cutaneous sensory afferents. As such, it provides a model to assess whether the status of epidermal innervation as determined by skin biopsy or quantitative sensory testing (QST) of small- and large-diameter sensory afferents might serve as predictors of response to topical, locally active treatment. In this study we assessed associations between epidermal nerve fiber (ENF) densities, sensory nerve conduction studies (NCS), QST, and response to a 5% lidocaine patch in patients with painful distal sensory neuropathies. We observed no association between distal leg epidermal and subepidermal innervation and response to the lidocaine patch. Several patients with complete loss of distal leg ENF showed a response to the lidocaine patch. Similarly we observed no consistent association between treatment response and QST for vibration, cooling, warm, heat-pain, and cold-pain thresholds, or distal sensory NCS. Thus, distal-leg skin biopsy, QST, and sensory NCS cannot be used to identify patients with painful polyneuropathy likely to respond to a lidocaine patch in clinical practice. Further studies are required to clarify precisely the mechanism and site of action of the lidocaine patch in patients with peripheral neuropathic pain.

Aged↗
PubMed2006

Ion channel targets and treatment efficacy in neuropathic pain.

UNLABELLED: Chronic neuropathic pain due to injury or dysfunction of the nervous system remains a formidable treatment challenge in spite of a growing range of medication choices. We review current clinical research supporting the use of ion channel modulators for neuropathic pain states. New modes of local drug delivery, novel Ca2+ channel targets, and increased choices for drugs with activity at Na+channels are transforming this longstanding therapeutic strategy. Clinical decision making is increasingly informed by a more nuanced understanding of the role of voltage-gated Na+channels (VGSCs) and Ca2+ channels (VGCCs) in the pathophysiology of nerve injury. Although holding great promise for the future, mechanism-based approaches to treatment will require greater understanding of the analgesic mechanisms of drug action and of the relationships between pathophysiologic mechanisms and clinical presentation. PERSPECTIVE: Treatment options for neuropathic pain targeting ion channels have grown rapidly in the past decade. An evolving body of clinical research supports the widespread use of this longstanding therapeutic strategy. Improved efficacy of ion channel modulators hinges upon further elucidation of the relationship between signs and symptoms of pain and underlying pathophysiology.

Calcium Channel Blockers↗
PubMed2006

Risk factors for chronic pain following breast cancer surgery: a prospective study.

UNLABELLED: Chronic pain following breast cancer surgery is associated with decreased health-related quality of life and is a source of additional psychosocial distress in women who are already confronting the multiple stresses of cancer. Few prospective studies have identified risk factors for chronic pain following breast cancer surgery. Putative demographic, clinical, and psychosocial risk factors for chronic pain were evaluated prospectively in 95 women scheduled for breast cancer surgery. In a multivariate analysis of the presence of chronic pain, only younger age was associated with a significantly increased risk of developing chronic pain 3 months after surgery. In an analysis of the intensity of chronic pain, however, more invasive surgery, radiation therapy after surgery, and clinically meaningful acute postoperative pain each independently predicted more intense chronic pain 3 months after surgery. Preoperative emotional functioning variables did not independently contribute to the prediction of either the presence or the intensity of chronic pain after breast cancer surgery. These findings not only increase understanding of risk factors for chronic pain following breast cancer surgery and the processes that may contribute to its development but also provide a basis for the development of preventive interventions. PERSPECTIVE: Clinical variables and severe acute pain were risk factors for chronic pain following breast cancer surgery, but psychosocial distress was not, which provides a basis for hypothesizing that aggressive management of acute postoperative pain may reduce chronic pain.

Acute Disease↗
PubMed2006

Do pain qualities and spatial characteristics make independent contributions to interference with physical and emotional functioning?

UNLABELLED: Although pain is acknowledged to be a multidimensional experience that can vary in intensity, quality (eg, burning, sensitive), and spatial characteristics (eg, location on body, perceived depth), its qualitative and spatial domains continue to be rarely assessed in pain clinical trials. One factor that may be contributing to the relatively rare assessment of pain quality and spatial characteristics is the lack of research addressing whether knowledge about these aspects of pain contributes important information beyond that provided by pain intensity alone. For example, there is no research that has examined whether measures of pain quality and perceived depth add anything to the understanding of the impact of pain on function. In the current study, secondary analyses of pretreatment data from clinical trials of patients from 3 diagnostic groups (osteoarthritis, low back pain, and peripheral neuropathy) indicated that measures of pain quality and perceived depth were significantly associated with pain interference with functioning, independent of global pain intensity and unpleasantness. No single pain descriptor emerged as universally important, however, although the findings suggest that: 1) sharp, deep, and perhaps especially sensitive pain may be important in patients with painful peripheral neuropathy; 2) sharp, sensitive, itchy, deep, and surface pain may be key pain descriptors important to persons with low back pain; and 3) perhaps deep pain may be the sole key pain descriptor important among persons with osteoarthritis. The findings support the potential utility of including measures of specific pain qualities and perceived depth in pain clinical trials and provide an initial empirical basis for determining which pain descriptors may be most closely linked to patient functioning. PERSPECTIVE: Specific pain qualities, such as sharp, sensitive, and itchy pain, and perceived depth of pain appear to play a significant and unique role in the prediction of pain interference in addition to global pain intensity and unpleasantness. These findings suggest that measures of these specific pain domains could play an important role in understanding the impact of pain on patient functioning.

Activities of Daily Living↗
PubMed2006

Use of the cumulative proportion of responders analysis graph to present pain data over a range of cut-off points: making clinical trial data more understandable.

In randomized controlled trials, no single definition of response is ideal for all purposes. We propose a method to present in a simple fashion the likelihood of response over a full range of response levels, which will facilitate a better understanding of clinical trial data. We present the technique called the cumulative proportion of responders analysis (CPRA) and its application to four pain clinical trial data sets as examples. The CPRA can be used to present the proportion of responders over the entire range of possible cut-off points as a graph. This allows the reader to compare treatment groups at any responder level that is valid for their patient population. Whether as a primary or secondary approach to a clinical trial of pain therapy, the display of data in a CPRA format may be useful in the understanding of results and applicability to patient care.

Analgesics↗
PubMed2005

Placebo response in clinical trials of depression and its implications for research on chronic neuropathic pain.

This article reviews studies of the placebo response in antidepressant clinical trials, describes methods that have been attempted to decrease it, and discusses implications of the placebo response in depression for research on treatments for neuropathic pain. Literature reviews and research studies examining the placebo response in clinical trials of treatments for depression were reviewed. Existing data suggest that the placebo response in antidepressant clinical trials is substantial and that a high placebo response in a clinical trial is associated with a reduced likelihood of demonstrating the statistical superiority of antidepressant treatment vs. placebo. Attempts to decrease the placebo response in antidepressant clinical trials have generally not been effective. In addition, there is little evidence that decreasing the placebo response rate makes it more likely that superiority of active vs. placebo treatment will be demonstrated. Analyses of neuropathic pain clinical trial databases should be conducted to examine factors associated with trial outcomes. Aspects of neuropathic pain clinical trials that require further consideration or investigation include the following: (a) exclusion of patients with mild pain severity; (b) exclusion of patients with short episode duration; (c) maximizing reliability, validity, and responsiveness of outcome measures; (d) minimizing extraneous contact with investigative staff and other sources of nonspecific therapeutic effects; (e) trial duration; (f) minimizing the number of treatment groups; (g) flexible vs. fixed dose designs; (h) strategies for identifying patients and accelerating enrollment; (i) identification of run-in periods that reduce the placebo response rate; and (j) registration of clinical trials and publication of negative studies.

Antidepressive Agents↗
PubMed2005

Risk factors for acute pain and its persistence following breast cancer surgery.

Although more severe acute postoperative pain increases the risk of chronic pain following breast cancer surgery, few studies have examined the characteristics of patients who develop greater acute pain. To identify risk factors for acute pain and its persistence one month following breast cancer surgery, a sample of 114 women scheduled for breast cancer surgery was assessed preoperatively for demographic, clinical, and emotional functioning variables that were hypothesized to be associated with acute pain severity. Clinically meaningful postoperative pain was assessed at follow-up interviews 2, 10, and 30 days after surgery. In univariate analyses, the risk of clinically meaningful acute pain was increased among women who were younger, unmarried, had more invasive surgeries, and had greater preoperative emotional distress. In multiple logistic regression analyses, greater preoperative anxiety was the only variable that made an independent contribution to predicting clinically meaningful acute pain at 2 days after surgery whereas younger age, being unmarried, and preoperative anxiety each made an independent contribution to predicting clinically meaningful acute pain that persisted from 2 to 30 days after surgery. These results increase understanding of neurobiologic mechanisms and psychosocial processes that contribute to the development of acute pain following breast cancer surgery and have implications for the development of interventions to prevent it.

Acute Disease↗
PubMed2005

Pregabalin for the treatment of fibromyalgia syndrome: results of a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: Fibromyalgia syndrome (FMS) is characterized by widespread musculoskeletal pain and lowered pain threshold. Other prominent symptoms include disordered sleep and fatigue. FMS affects an estimated 2% of the population, predominantly women. This trial was designed to evaluate the efficacy and safety of pregabalin, a novel alpha(2)-delta ligand, for treatment of symptoms associated with FMS. METHODS: This multicenter, double-blind, 8-week, randomized clinical trial compared the effects of placebo with those of 150, 300, and 450 mg/day pregabalin on pain, sleep, fatigue, and health-related quality of life in 529 patients with FMS. The primary outcome variable was the comparison of end point mean pain scores, derived from daily diary ratings of pain intensity, between each of the pregabalin treatment groups and the placebo group. RESULTS: Pregabalin at 450 mg/day significantly reduced the average severity of pain in the primary analysis compared with placebo (-0.93 on a 0-10 scale) (P </= 0.001), and significantly more patients in this group had >/=50% improvement in pain at the end point (29%, versus 13% in the placebo group; P = 0.003). Pregabalin at 300 and 450 mg/day was associated with significant improvements in sleep quality, fatigue, and global measures of change. Pregabalin at 450 mg/day improved several domains of health-related quality of life. Dizziness and somnolence were the most frequent adverse events. Rates of discontinuation due to adverse events were similar across all 4 treatment groups. CONCLUSION: Pregabalin at 450 mg/day was efficacious for the treatment of FMS, reducing symptoms of pain, disturbed sleep, and fatigue compared with placebo. Pregabalin was well tolerated and improved global measures and health-related quality of life.

Adult↗
PubMed2005

Assessment of pain quality in chronic neuropathic and nociceptive pain clinical trials with the Neuropathic Pain Scale.

UNLABELLED: Although a number of measures of pain qualities exist, little research has examined the potential for these measures to identify the unique effects of pain treatments on different pain qualities. We examined the utility of the Neuropathic Pain Scale (NPS) for assessing changes in pain qualities after open label lidocaine patch 5% in 3 samples of patients: patients with peripheral neuropathic pain, low back pain, and osteoarthritis. With one exception ("cold" pain in subjects with low back pain), each of the NPS items showed significant change after open label lidocaine patch. In addition, significantly larger changes were observed for the NPS items reflecting global pain intensity and pain unpleasantness and for items assessing sharp and deep pain than for items assessing cold, sensitive, and itchy pain. The pattern of changes in pain qualities did not differ across the 3 diagnostic groups, but it did differ from the patterns of changes in pain qualities associated with other analgesic treatments. The results support the potential utility of the NPS for assessing the patterns of changes in pain qualities that can be observed after pain treatment. PERSPECTIVE: Pain clinical trials that include measures of pain qualities, such as the NPS, might identify distinct patterns of treatment effects on those pain qualities. This research might be used to help clinicians target analgesics to match the specific qualities associated with a patient's pain and to better understand the mechanisms of analgesic effects in drug development programs.

Administration, Cutaneous↗
PubMed2005

A randomized, placebo-controlled trial of bupropion sustained release in chronic low back pain.

UNLABELLED: Clinical trials of the efficacy of antidepressant drugs in patients with chronic low back pain have had mixed results, possibly because of the different mechanisms of action of the drugs that have been studied. Because bupropion has a mechanism of action that differs from other antidepressants and has shown efficacy in neuropathic pain, a randomized, placebo-controlled, 2-period crossover trial was conducted to evaluate its efficacy in subjects with chronic low back pain. The primary efficacy variable was mean daily diary pain intensity ratings, and secondary pain intensity and relief outcomes included weekly pain intensity ratings, the McGill Pain Questionnaire (MPQ) Present Pain Intensity scale, pain relief ratings, and satisfaction with pain relief ratings. Adverse events were also assessed throughout the trial. Analyses were performed of an intention-to-treat sample of 44 patients, only 3 of whom met criteria for neuropathic low back pain. Daily and weekly pain intensity ratings, the MPQ Present Pain Intensity scale, and pain relief ratings were not significantly different following treatment with bupropion sustained release (SR) vs. placebo. These results suggest that bupropion SR was not significantly better than placebo in the treatment of patients with non-neuropathic chronic low back pain. PERSPECTIVE: Antidepressant medications that have both noradrenergic and serotonergic effects appear to have greater efficacy in patients with chronic low back pain than those with only serotonergic activity. We studied bupropion because it inhibits the reuptake of both norepinephrine and dopamine, but found no evidence of efficacy in patients with non-neuropathic chronic low back pain.

Adult↗
PubMed2005

Psychosocial risk factors for postherpetic neuralgia: a prospective study of patients with herpes zoster.

UNLABELLED: The results of previous studies using retrospective methods or small samples have suggested that there may be psychosocial risk factors for postherpetic neuralgia (PHN). We conducted a prospective study in which 110 patients with herpes zoster were assessed within the first month after rash onset with measures of acute pain and five broad domains of psychosocial functioning-physical, role, social, and emotional functioning, and stress and social support. Twenty of the 102 patients with follow-up data were diagnosed with PHN, defined as pain that had persisted for 4 months after rash onset. Measures of role functioning, personality disorder symptoms, and disease conviction during herpes zoster each made independent contributions to predicting either presence or intensity of PHN in logistic and linear regression analyses that controlled for relevant demographic and clinical variables, including age and acute pain intensity. These findings indicate that psychosocial variables are risk factors for the development of PHN. PERSPECTIVE: The results of this prospective study of patients with herpes zoster suggest that future research on the mechanisms and prevention of PHN should consider psychosocial as well as neurobiologic processes.

Activities of Daily Living↗