Risk-benefit assessment of opioids in chronic noncancer pain

Hybrid Statistical and Mechanistic Mathematical Model Guides Mobile Health Intervention for Chronic Pain

Nearly a quarter of visits to the emergency department are for conditions that could have been managed via outpatient treatment; improvements that allow patients to quickly recognize and receive appropriate treatment are crucial. The growing popularity of mobile technology creates new opportunities for real-time adaptive medical intervention, and the simultaneous growth of "big data" sources allows for preparation of personalized recommendations. Here we focus on the reduction of chronic suffering in the sickle cell disease (SCD) community. SCD is a chronic blood disorder in which pain is the most frequent complication. There currently is no standard algorithm or analytical method for real-time adaptive treatment recommendations for pain. Furthermore, current state-of-the-art methods have difficulty in handling continuous-time decision optimization using big data. Facing these challenges, in this study, we aim to develop new mathematical tools for incorporating mobile technology into personalized treatment plans for pain. We present a new hybrid model for the dynamics of subjective pain that consists of a dynamical systems approach using differential equations to predict future pain levels, as well as a statistical approach tying system parameters to patient data (both personal characteristics and medication response history). Pilot testing of our approach suggests that it has significant potential to well predict pain dynamics, given patients reported pain levels and medication usages. With more abundant data, our hybrid approach should allow physicians to make personalized, data-driven recommendations for treating chronic pain.

Acute Pain Management

Acute pain management is improving steadily over the past few years, but training and professional education are still lacking in many professions. Untreated or undertreated acute pain could have detrimental effects on the patient in terms of comfort and recovery from trauma or surgery. Acute undertreated pain can decrease a patient's vascular perfusion, increase oxygen demand, suppress the immune system, and possibly risk increased incidence of venous thrombosis. Although acute postoperative pain needs to be managed aggressively, patients are most vulnerable during this period for developing adverse effects, and therefore, patient assessment and careful drug therapy evaluation are necessary processes in therapeutic planning. Acute pain management requires careful and thorough initial assessment and follow-up reassessment in addition to frequent dosage adjustments, and managing analgesic induced side effects. Analgesic selection and dosing must be based on the patient's past and recent analgesic exposure. There is no single acute pain management regimen that is suitable for all patients. Analgesics must be tailored to the individual patient.

Effectiveness of Tapentadol Prolonged Release (PR) Compared with Oxycodone/Naloxone PR for the Management of Severe Chronic Low Back Pain with a Neuropathic Component: A Randomized, Controlled, Open-Label, Phase 3b/4 Study

OBJECTIVE

To evaluate the effectiveness of tapentadol prolonged release (PR) vs. oxycodone/naloxone PR in non-opioid-pretreated patients with severe chronic low back pain with a neuropathic pain component.

METHODS

Eligible patients (average pain intensity [numerical rating scale-3 (NRS-3)] ≥6; painDETECT positive/unclear) were randomized to twice-daily tapentadol PR 50 mg or oxycodone/naloxone PR 10 mg/5 mg. After a 21-day titration (maximum twice-daily doses: tapentadol PR 250 mg, or oxycodone/naloxone PR 40 mg/20 mg plus oxycodone PR 10 mg), target doses were continued for 9 weeks. The primary effectiveness endpoint was the change in NRS-3 from baseline to final evaluation; the exact repeated confidence interval (RCI) for tapentadol PR minus oxycodone/naloxone PR was used to establish noninferiority (upper limit <1.3) and superiority (confirmatory analyses).

RESULTS

For the primary effectiveness endpoint, tapentadol PR was noninferior to oxycodone/naloxone PR (97.5% RCI: [-1.820, -0.184]; P < 0.001). This exact RCI also yielded evidence of superiority for tapentadol PR vs. oxycodone/naloxone PR (significantly greater reduction in pain intensity; P = 0.003). Improvements (baseline to final evaluation) in painDETECT and Neuropathic Pain Symptom Inventory scores were significantly greater with tapentadol PR vs. oxycodone/naloxone PR (all P ≤ 0.005).

CONCLUSIONS

The study was formally shown to be positive and demonstrated, in the primary effectiveness endpoint, the noninferiority for tapentadol PR vs. oxycodone/naloxone PR. The effectiveness of tapentadol PR was superior to that of oxycodone/naloxone PR by means of clinical relevance and statistical significance (confirmatory evidence of superiority). Tapentadol PR was associated with significantly greater improvements in neuropathic pain-related symptoms and global health status than oxycodone/naloxone PR and with a significantly better gastrointestinal tolerability profile. Tapentadol PR may be considered a first-line option for managing severe chronic low back pain with a neuropathic pain component.

The use of combined spinal-epidural technique to compare intrathecal ziconotide and epidural opioids for trialing intrathecal drug delivery

SUMMARY Choosing the initial medications for intrathecal delivery is often confusing and not standardized. We describe a novel way for using a combined spinal-epidural technique to compare two first-line medications for intrathecal delivery; ziconotide and morphine (or hydromorphone). Five patients with intractable chronic or cancer pain were elected to have an intrathecal drug delivery system implanted for pain management. Each patient was given a 3-day inpatient trial with the combined spinal-epidural technique. The Visual Analog Scale, Numerical Rating Scale, short-term McGill questionnaire and opioid consumption were monitored daily. The results were used to develop a paradigm to describe how ziconotide can be used in practice.

Effectiveness and Safety of Tapentadol Prolonged Release (PR) Versus a Combination of Tapentadol PR and Pregabalin for the Management of Severe, Chronic Low Back Pain With a Neuropathic Component: A Randomized, Double-blind, Phase 3b Study

OBJECTIVE

To evaluate the effectiveness and tolerability of tapentadol PR monotherapy versus tapentadol PR/pregabalin combination therapy for severe, chronic low back pain with a neuropathic component.

METHODS

Eligible patients had painDETECT "unclear" or "positive" ratings and average pain intensity ≥ 6 (11-point NRS-3 [average 3-day pain intensity]) at baseline. Patients were titrated to tapentadol PR 300 mg/day over 3 weeks. Patients with ≥ 1-point decrease in pain intensity and average pain intensity ≥ 4 were randomized to tapentadol PR (500 mg/day) or tapentadol PR (300 mg/day)/pregabalin (300 mg/day) during an 8-week comparative period.

RESULTS

In the per-protocol population (n = 288), the effectiveness of tapentadol PR was clinically and statistically comparable to tapentadol PR/pregabalin based on the change in pain intensity from randomization to final evaluation (LOCF; LSMD [95% CI], -0.066 [-0.57, 0.43]; P < 0.0001 for noninferiority). Neuropathic pain and quality-of-life measures improved significantly in both groups. Tolerability was good in both groups, in line with prior trials in the high dose range of 500 mg/day for tapentadol PR monotherapy, and favorable compared with historical combination trials of strong opioids and anticonvulsants for combination therapy. The incidence of the composite of dizziness and/or somnolence was significantly lower with tapentadol PR (16.9%) than tapentadol PR/pregabalin (27.0%; P = 0.0302).

CONCLUSIONS

Tapentadol PR 500 mg is associated with comparable improvements in pain intensity and quality-of-life measures to tapentadol PR 300 mg/pregabalin 300 mg, with improved central nervous system tolerability, suggesting that tapentadol PR monotherapy may offer a favorable treatment option for severe low back pain with a neuropathic component.

Chronic pain management by ethnically and racially diverse older adults: pharmacological and nonpharmacological pain therapies

SUMMARY Aims: Exploration of racial and ethnic group differences in noncancer chronic pain management in older adults. Participants & methods: Qualitative data, which were collected in semistructured face-to-face interviews with 44 racially and ethnically diverse community-dwelling older adults (ten African–Americans, ten Hispanics, 12 Afro–Caribbeans and 12 non-Hispanic whites), were analyzed using constant comparative analysis. Results: The three racial and ethnic minority groups were more likely to use culturally based treatments (e.g., herbal tea and avocado leaves), home remedies and folk medicine, and/or psychological therapies (e.g., distraction and relaxation) than non-Hispanic whites to manage chronic pain. African–Americans relied on religious coping methods. Non-Hispanic whites were more likely to use physical interventions such as massage and chiropractic treatment. Conclusion: Study findings suggest differences by ethnicity in preferred pain interventions for an older adult population.

Post hoc analyses of data from a 90-day clinical trial evaluating the tolerability and efficacy of tapentadol immediate release and oxycodone immediate release for the relief of moderate to severe pain in elderly and nonelderly patients

OBJECTIVE

To evaluate the tolerability and efficacy of tapentadol immediate release (IR) and oxycodone IR for relief of moderate to severe pain in elderly and nonelderly patients.

METHODS

Post hoc data analyses were conducted on a 90-day randomized, phase 3, double-blind, flexible-dose study (ClinicalTrials.gov: NCT00364546) of adults with moderate to severe lower back pain or osteoarthritis pain who received tapentadol IR 50 mg or 100 mg, or oxycodone HCl IR 10 mg or 15 mg every 4 h to 6 h as needed for pain relief. Treatment-emergent adverse events and study discontinuations were recorded.

RESULTS

Data from 849 patients randomly assigned (4:1 ratio) to treatment with a study drug (tapentadol IR [n=679] or oxycodone IR [n=170]) were analyzed according to age (younger than 65 years of age [nonelderly], or 65 years of age or older [elderly]) and treatment group. Among elderly patients, incidences of constipation (19.0% versus 35.6%) and nausea or vomiting (30.4% versus 51.1%) were significantly lower with tapentadol IR versus oxycodone IR (all P<0.05). Initial onsets of nausea and constipation occurred significantly later with tapentadol IR versus oxycodone IR (both P<=0.031). Tapentadol IR-treated elderly patients had a lower percentage of days with constipation than oxycodone IR-treated patients (P=0.020). For tapentadol IR- and oxycodone IR-treated elderly patients, respectively, incidences of study discontinuation due to gastrointestinal treatment-emergent adverse events were 15.8% and 24.4% (P=0.190). Tapentadol IR and oxycodone IR provided similar pain relief, with no overall age-dependent efficacy differences (mean pain scores [11-point numerical rating scale] decreased from 7.0 and 7.2 at baseline, to 4.9 and 5.2 at end point, respectively).

CONCLUSIONS

Tapentadol IR was safe and effective for the relief of lower back pain and osteoarthritis pain in elderly patients, and was associated with a better gastrointestinal tolerability profile than oxycodone IR.

Effectiveness and safety of tapentadol prolonged release for severe, chronic low back pain with or without a neuropathic pain component: results of an open-label, phase 3b study

OBJECTIVE

This open-label, phase 3b study evaluated the effectiveness and tolerability of tapentadol prolonged release and tapentadol immediate release (for acute pain episodes) for severe, chronic low back pain with or without a neuropathic pain component that was inadequately managed in patients taking World Health Organization (WHO) Step I or II analgesics or who were not regularly treated with analgesics.

RESEARCH DESIGN AND METHODS

Average baseline pain intensity was greater than 5 (11-point numerical rating scale-3 [NRS-3; 3-day average pain intensity]) with WHO Step I or II analgesics and greater than 6 with no regular analgesic regimen. WHO Step II analgesics were discontinued before starting study treatment; WHO Step I analgesics or co-analgesics were continued at the same dose. Patients received tapentadol prolonged release (50-250 mg bid) during a 5-week titration and 7-week maintenance period. Tapentadol immediate release was permitted for acute pain episodes (tapentadol prolonged release and immediate release maximum combined dose, ≤500 mg/day). The painDETECT questionnaire was used to define subsets of patients based on the probability of a neuropathic pain component to their low back pain as 'negative', 'unclear', or 'positive'.

CLINICAL TRIAL REGISTRATION

NCT00983385.

MAIN OUTCOME MEASURE

The primary endpoint was the change from baseline to week 6 in average pain intensity (NRS-3), using the last observation carried forward to impute missing scores.

RESULTS

In the painDETECT negative (n = 49) and unclear/positive (n = 126) subsets, respectively, mean (SD) changes in pain intensity from baseline to week 6 were -2.4 (2.18) and -3.0 (2.07; both p < 0.0001). Among patients who had not received prior WHO Step II treatment, lower doses of tapentadol prolonged release were generally required with increasing likelihood of a neuropathic pain component. Based on the painDETECT questionnaire and the Neuropathic Pain Symptom Inventory (NPSI), tapentadol prolonged release treatment was also associated with significant improvements in neuropathic pain symptoms, with decreases in the number of pain attacks and the duration of spontaneous pain in the last 24 hours in patients with low back pain with a neuropathic pain component (painDETECT unclear or positive score at baseline or screening). The most common treatment-emergent adverse events (incidence ≥10%, n = 176) were nausea, dizziness, headache, dry mouth, fatigue, constipation, diarrhea, nasopharyngitis, and somnolence.

CONCLUSIONS

Tapentadol prolonged release was well tolerated and effective for managing severe, chronic low back pain with or without a neuropathic pain component.

Factor structure of pain medication questionnaire in community-dwelling older adults with chronic pain

OBJECTIVES

This study was to develop a version of the Pain Medication Questionnaire (PMQ) specific to the elderly chronic pain population and to identify relevant subscales and items for that population. Exploratory factor analysis (EFA) was conducted to assess the factor structure of the PMQ, to eliminate items that are not appropriate for this population, and to improve ease of administration in the elderly population.

METHODS

Data were obtained through a survey administered to older adults with chronic pain who consumed opioid medications in a cross-sectional study at outpatient clinics affiliated with the Baltimore Veterans Affairs Medical Center and the University of Maryland Medical System. EFA was conducted on the PMQ in the geriatric chronic pain population, which was compared with the PMQ studies from the general chronic pain population.

RESULTS

A two-factor solution yielded Factor 1 with four items and Factor 2 with three items; 18 items did not load significantly on either factor, and only seven items loaded significantly on either factor. All of the chosen factor loadings ranged from 0.41 to 0.88.

CONCLUSION

  The findings suggest that, although a small number of the items were identified from the overall scale, they adequately explain two relatively unique factors pertaining to pain management among older adults. This preliminary study suggests that the seven-item PMQ may be useful in assessing opioid medication misuse in community-dwelling older adults with chronic pain. Future studies are needed to confirm the reliability, validity, and factor structure of this modified PMQ in the geriatric population.

Review of the effect of opioid-related side effects on the undertreatment of moderate to severe chronic non-cancer pain: tapentadol, a step toward a solution?

OBJECTIVE

Opioids are among the most effective and potent analgesics currently available. Their utility in the management of pain associated with cancer, acute injury, or surgery is well recognized. However, extending the application of opioids to the management of chronic non-cancer pain has met with considerable resistance. This resistance is due in part to concerns related to gastrointestinal and central nervous system-related adverse events as well as issues pertaining to regulatory affairs, the development of tolerance, incorrect drug usage, and addiction. This review focuses on the incidence of opioid-related side effects and the patient and physician barriers to opioid therapy for chronic non-cancer pain. Tapentadol, a centrally acting analgesic with two mechanisms of action, micro-opioid agonism and norepinephrine reuptake inhibition, may be considered to be a partial solution to some of these issues.

METHODS

MEDLINE was searched for English-language articles from 1950 to February 2010 using the terms chronic non-cancer pain and opioids together and in combination with undertreatment, adherence, and compliance.

RESULTS

The majority of patients treated with traditional opioids experience gastrointestinal- or central nervous system-related adverse events, most commonly constipation, nausea, and somnolence. These side effects often lead to discontinuation of opioid therapy. Concerns about side effects, analgesic tolerance, dependence, and addiction limit the use of opioids for the management of chronic pain. Treatment with tapentadol appears to provide several advantages of an analgesic with a more favorable side-effect profile than the classic micro-opioid receptor agonist oxycodone (especially related to gastrointestinal tolerability).

CONCLUSIONS

The pervasiveness of opioid-associated side effects and concerns related to tolerance, dependence, and addiction present potential barriers to the approval and use of opioids for the management of chronic non-cancer pain. The lower incidence of opioid-associated adverse events and possibly fewer withdrawal symptoms, combined with a satisfactory analgesic profile associated with tapentadol, suggest its potential utility for the management of chronic non-cancer pain. This review will focus on the incidence of opioid-related side effects and barriers to opioid therapy that are available as English-language articles in the MEDLINE index, and as such, it is a representative but not an exhaustive review of the current literature.

Classification Accuracy of MMPI-2 Validity Scales in the Detection of Pain-Related Malingering

The purpose of this study was to determine the accuracy of Minnesota Multiphasic Personality Inventory 2nd edition (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) validity indicators in the detection of malingering in clinical patients with chronic pain using a hybrid clinical-known groups/simulator design. The sample consisted of patients without financial incentive ( n = 23), nonmalingering patients with financial incentive ( n = 34), patients definitively determined to be malingering based on published criteria ( n = 32), and college students asked to simulate pain-related disability ( n = 26). The MMPI-2 validity scales differentiated malingerers from nonmalingerers with a high degree of accuracy. Hypochondriasis and Hysteria were also effective. For all variables except Scale L, more extreme scores were associated with higher specificity. This study demonstrates that the MMPI-2 is capable of differentiating intentional exaggeration from the effects on symptom report of chronic pain, genuine psychological disturbance, and concurrent stress associated with pursuing a claim in a medico-legal context.

A Critical Analysis of the Tender Points in Fibromyalgia

OBJECTIVE

To pilot methodologies designed to critically assess the American College of Rheumatology's (ACR) diagnostic criteria for fibromyalgia.

DESIGN

Prospective, psychophysical testing.

SETTING

An urban teaching hospital.

SUBJECTS

Twenty-five patients with fibromyalgia and 31 healthy controls (convenience sample).

INTERVENTIONS

Pressure pain threshold was determined at the 18 ACR tender points and five sham points using an algometer (dolorimeter).

OUTCOME MEASURES

The patients "algometric total scores" (sums of the patients' average pain thresholds at the 18 tender points) were derived, as well as pain thresholds across sham points.

RESULTS

The "algometric total score" could differentiate patients with fibromyalgia from normals with an accuracy of 85.7% (P < 0.001). Even a single tender point had a diagnostic accuracy between 75% and 89%. Although fibromyalgics had less pain across sham points than across ACR tender points, sham points also could be used for diagnosis (85.7%; Ps < 0.001). Hierarchical cluster analysis showed that three points could be used for a classification accuracy equivalent to the use of all 18 points.

CONCLUSIONS

There was a significant difference in the "algometric total score" between patients with fibromyalgia and controls, and we suggest this quantified (although subjective) approach may represent a significant improvement over the current diagnostic scheme, but this must be tested vs other painful conditions. The points specified by the ACR were only modestly superior to sham points in making the diagnosis. Most importantly, this pilot suggests single points, smaller groups of points, or sham points may be as effective in diagnosing fibromyalgia as the use of all 18 points, and suggests methodologies to definitively test that hypothesis.

Who will prescribe? A proposal for specialized opioid management clinics

There is currently no uniform system of providing care for patients with chronic nonmalignant pain who require ongoing opioid maintenance therapy. Some patients receive care in a general practice setting, while others are managed in pain clinics where opioid management is only one of many services provided. Current events involving increased abuse and diversion of opioid medications suggest the need for improved case management and coordination when opioids are used for chronic nonmalignant pain. Based on the model of anticoagulation clinics, the author proposes the development of specialized opioid management clinics. These clinics would: 1) evaluate patient-specific risks and benefits of therapy; 2) supervise the mechanics of opioid prescribing; 3) provide systematic and secure monitoring of patient adherence to therapy; 4) assess goals of therapy and progress towards them; 5) coordinate opioid treatment with other pain-related treatment; 6) supply education to patients, family members and caregivers about the appropriate use of opioids; 7) maintain communication with other caregivers and pharmacists; and 8) provide regular psychological assistance and support for patients.

Naloxone, not proglumide or MK-801, alters effects of morphine preexposure on morphine-induced taste aversions

Both cholecystokinin (CCK) antagonists and N-methyl-D-aspartate (NMDA) antagonists block or reduce the development of morphine tolerance in several analgesic assays. The present experiments were performed to assess the ability of the CCK antagonist proglumide and the NMDA antagonist MK-801 to affect tolerance to the aversive properties of morphine as indexed by conditioned taste aversion (CTA) learning. Specifically, male Sprague-Dawley rats were exposed to either vehicle or morphine (5 mg/kg) in combination with either proglumide (5 mg/kg; Experiment 1), MK-801 (0.1 mg/kg; Experiment 2) or naloxone (1, 3.2 mg/kg; Experiment 3). Saccharin was then presented and was followed by an injection of either vehicle or morphine (10 mg/kg). Animals preexposed to and conditioned with morphine acquired an attenuated morphine-induced aversion to saccharin. While neither proglumide nor MK-801 had an effect on this attenuation, naloxone blocked the effects of morphine preexposure, suggesting that neither CCK nor NMDA may be involved in the aversive effects of morphine (or their modulation by drug exposure). That the attenuating effects of morphine preexposure on a morphine-induced CTA can be blocked suggests that the weakening of the aversive effects of morphine with chronic use can be prevented, an effect that may have implications for overall drug acceptability.

The use of opioids in the treatment of osteoarthritis: when, why, and how?

As life expectancy increases every decade, the incidence and prevalence of osteoarthritis (OA) also will increase. Despite progress in our knowledge of the pathophysiology of OA, the management of OA-mediated pain continues to challenge physicians. Concern regarding the cardiovascular effects of cyclooxygenase-2 inhibitors and the gastrointestinal and renal side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) in general has limited the use of these medications in the management of chronic non-cancer pain. Appropriately dosed and monitored use of opioids for OA pain, when more conservative methods have failed, has potentially fewer life-threatening complications associated with it than the more commonly and often less successfully employed pharmacotherapeutic approaches to care. When used as part of a multimodal approach to pain control, opioids are a safe and effective treatment for joint pain, including that of OA. Patients for whom NSAIDs are contraindicated, or for whom combined acetaminophen, tramadol, and NSAID therapy is ineffective, may be started on low-dose opioids and titrated as needed and tolerated. Patient education and informed consent, exercise, complementary medicine, and the use of a controlled substance agreement increases the likelihood of patient compliance with treatment guidelines, improving functional capacity and quality of life.

Long-term tolerability of tramadol LP, a new once-daily formulation, in patients with osteoarthritis or low back pain

INTRODUCTION

Tramadol hydrochloride is a centrally acting analgesic, which possesses opioid agonist properties and activates monoaminergic spinal inhibition of pain. An oral, once a day, sustained release formulation of tramadol is thought to be advantageous compared with immediate release preparations as it prevents plasma peaks associated with increased side-effects of the drug. It may also improve compliance. The purpose of the study was to assess the long-term safety of a new sustained-release formulation of tramadol (tramadol LP) in patients with knee or hip osteoarthritis and in patients with refractory low back pain.

STUDY DESIGN

The design was a phase III, open, multicentre, international, tolerability study with tramadol LP at a dose titrated by the patient between 100 and 400 mg once daily, according to the intensity of pain. The treatment was administered for a continuous period of 4 weeks followed by an intermittent intake of 5 months in 204 patients. The safety criteria for evaluation were recording of adverse events, laboratory tests, electrocardiogram, radiography, global tolerability assessed by the patient and the investigators.

RESULTS

Long-term use of tramadol LP was reasonably well tolerated. Most of the reported adverse events were expected and occurred within the first month of treatment. Roughly half of the patients (49%) reported adverse events, of which 66% were related to treatment. Gastrointestinal events (nausea and vomiting) were the most frequent. Serious adverse events were reported in 6.4% of patients, from which only two cases were related to treatment. There was no sign of tolerance development and the percentage of patients presenting withdrawal symptoms after the end of treatment was low (6%).

CONCLUSION

Long-term treatment with tramadol LP once daily is generally safe in patients with osteoarthritis or refractory low back pain.

New workers' compensation legislation: expected pharmaceutical cost savings

BACKGROUND

California Workers' Compensation (WC) system costs are under review. With recently approved California State Assembly Bill (AB) 749 and Senate Bill (SB) 228, an assessment of proposed pharmaceutical cost savings is needed.

METHODS

A large workers' compensation database provided by the California Workers' Compensation Institute (CWCI) and Medi-Cal pharmacy costs obtained from the State Drug Utilization Project are utilized to compare frequency, costs and savings to Workers' Compensation in 2002 with the new pharmacy legislation.

RESULTS

Compared to the former California Workers' Compensation fee schedule, the newly implemented 100% Medi-Cal fee schedule will result in savings of 29.5% with a potential total pharmacy cost savings of $125 million. Further statistical analysis demonstrated that a large variability in savings across drugs could not be controlled with this drug pricing system.

CONCLUSIONS

Despite the large savings in pharmaceuticals, inconsistencies between the two pharmaceutical payment systems could lead to negative incentives and uncertainty for long-term savings. Proposed alternative pricing systems could be considered. However, pain management implemented along with other cost containment strategies could more effectively reduce overall drug spending in the workers' compensation system.

Impact of long-term use of opioids on quality of life in patients with chronic, non-malignant pain

OBJECTIVE

The use of opioids in the management of non-malignant pain remains controversial. For many physicians, pain relief stemming from opioid use is not enough unless there is also a noticeable change in quality of life (QoL) and patient functioning. The impact of long-term opioid treatment on patients' QoL has been investigated in a limited number of trials, and these studies differ considerably with respect to their design and principal findings. This systematic review presents the results of these studies.

DESIGN AND METHODS

MEDLINE (1966 to November/December 2004), EMBASE (1974 to November/December 2004), the Oxford Pain Relief Database (Bandolier; 1954-1994) and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for relevant papers by combining search terms for function with terms for opioid analgesia, non-malignant and pain. Studies were eligible for inclusion if they met all of the pre-defined criteria specifying study design, population, intervention and outcome measures.

RESULTS

Eleven studies evaluated long-term treatment with opioids in patients with chronic, non-malignant pain and assessed QoL (N = 2877). Six studies were randomised trials and the remaining five were observational studies. In general, the former had higher Jadad rating scores for the quality of the paper than the latter. Of the four randomised studies in which baseline QoL was reported, three showed an improvement in QoL. Similarly, of the five observational studies, a significant improvement in QoL was reported in four.

CONCLUSIONS

There is both moderate/high- and low-quality evidence suggesting that long-term treatment with opioids can lead to significant improvements in functional outcomes, including QoL, in patients with chronic, non-malignant pain. However, further methodologically rigorous investigations are required to confirm the long-term QoL benefit of opioid treatment in these patients, and to elucidate the effect of physical tolerance, withdrawal and addiction, which are all associated with long-term use of opioids, on patients' functional status.

On the diagnosis of malingered pain-related disability: lessons from cognitive malingering research

BACKGROUND CONTEXT

Pain-related disability is a complex phenomenon. Malingering is a potential factor in the management of patients with pain. Methodological problems and inappropriate expectations regarding diagnostic accuracy have hampered the study of malingering detection in pain. In contrast, the study of cognitive malingering in neuropsychology has led to the development of many highly accurate and reliable detection techniques. This paper applies the methods and logic that have been successful for identifying cognitive malingering to the problem of malingering in patients with pain.

PURPOSE

Outline the logic of a research methodology for studying malingering detection in pain and introduce a system for the diagnosis of malingering in pain.

STUDY DESIGN

Literature review and conceptual synthesis.

METHODS

Examination of the research methodology and diagnostic scheme used in the study of cognitive malingering; adaptation of these methods to the problem of malingering in pain.

RESULTS

Lessons derived from the study of cognitive malingering were used to generate recommendations to enhance research into detection and diagnosis of malingered pain-related disability. A comprehensive, multidimensional system for diagnosing malingering in pain-related disability was proposed.

CONCLUSIONS

Pain-related disability is a multifaceted phenomenon, therefore malingering can occur in different and sometimes multiple dimensions. It is presently possible to accurately detect and diagnose malingering in some patients with pain. More work is needed for some detection techniques to be appropriately calibrated in pain populations. This work must focus on controlling the false positive error rate.

Chronic neuropathic pain. Mechanisms, diagnosis, and treatment

BACKGROUND

The management of chronic pain represents a significant public health issue in the United States. It is both costly to our health care system and devastating to the patient's quality of life. The need to improve pain outcomes is reflected by the congressional declaration of the present decade as the "Decade of Pain Control and Research," and the acknowledgment in January 2001 of pain as the "fifth vital sign" by the Joint Commission of Healthcare Organizations.

REVIEW SUMMARY

At present, therapeutic options are largely limited to drugs approved for other conditions, including anticonvulsants, antidepressants, antiarrhythmics, and opioids. However, treatment based on the underlying disease state (eg, postherpetic neuralgia, diabetic neuropathy) may be less than optimal, in that 2 patients with the same neuropathic pain syndrome may have different symptomatology and thus respond differently to the same treatment. Increases in our understanding of the function of the neurologic system over the last few years have led to new insights into the mechanisms underlying pain symptoms, especially chronic and neuropathic pain.

CONCLUSIONS

The rapidly evolving symptom- and mechanism-based approach to the treatment of neuropathic pain holds promise for improving the quality of life of our patients with neuropathic pain.

Liver and kidney toxicity in chronic use of opioids: An experimental long term treatment model

In this study, histopathological and biochemical changes due to chronic usage of morphine or tramadol in liver and kidney were assessed in rats. Thirty male Wistar rats (180-220 g) were included and divided into three groups. Normal saline (1 ml) was given intraperitoneally as placebo in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4, 8, 10 mg/kg/day in the first, second and the third ten days of the study, respectively. Tramadol group (n = 10), received the drug intraperitoneally at doses of 20, 40 and 80 mg/kg/day in the first, second and the third ten days of the study, respectively. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatinin, blood urea nitrogen (BUN) and malondialdehyde (MDA) levels were measured in the serum. Liver and kidney specimens were evaluated by light microscopy. Serum ALT, AST, LDH, BUN and creatinin levels were significantly higher in morphine group compared to the control group. Serum LDH, BUN and creatinin levels were significantly increased in the morphine group compared to the tramadol group. The mean MDA level was significantly higher in morphine group compared to the tramadol and control groups (P < 0.05). Light microscopy revealed severe centrolobular congestion and focal necrosis in the liver of morphine and tramadol groups, but perivenular necrosis was present only in the morphine group. The main histopathologic finding was vacuolization in tubular cells in morphine and tramadol groups. Our findings pointed out the risk of increased lipid peroxidation, hepatic and renal damage due to long term use of opioids, especially morphine. Although opioids are reported to be effective in pain management, their toxic effects should be kept in mind during chronic usage.

Opioid neurotoxicity: comparison of morphine and tramadol in an experimental rat model

Histopathologic changes in rat brain due to chronic use of morphine and/or tramadol in progressively increased doses were investigated in this study. Thirty male Wistar rats (180-220 g) were included and divided into three groups. Normal saline (1 ml/kg) was given intraperitoneally as placebo in the control group (n = 10). Morphine group (n = 10) received morphine intraperitoneally at a dose of 4 mg/kg/day for the first 10 days, 8 mg/kg/day between 11-20 days, and 12 mg/kg/day between 21-30 days. The tramadol group (n = 10) received the drug intraperitoneally at doses of 20, 40, and 80 mg/kg/day in the first, second, and the third 10 days of the study, respectively. All rats were decapitated on the 30th day and the brain was removed intact for histology. The presence and the number of red neurons, which are a histologic marker of apoptosis, were investigated in the parietal, frontal, temporal, occipital, entorhinal, pyriform, and hippocampal CA1, CA2, CA3 regions. Red neurons were found in morphine and tramadol groups but not in the control group. The total number of red neurons was not different in morphine and tramadol groups, but the numbers of red neurons were significantly higher in the temporal and occipital regions in tramadol group as compared with the morphine group (p < .05). In conclusion, chronic use of morphine and/or tramadol in increasing doses is found to cause red neuron degeneration in the rat brain, which probably contributes to cerebral dysfunction. These findings should be taken into consideration when chrome use of opioids is indicated.

Efficacy and tolerability of sustained-release tramadolin the treatment of symptomatic osteoarthritis of the hip or knee: A multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Opioid analgesics may be a useful alternative in patients with osteoarthritis who have not responded to first-line treatment with acetaminophen and in whom nonsteroidal anti-inflammatory drugs are contraindicated, ineffective, or poorly tolerated.

OBJECTIVE

This study compared the efficacy and tolerability of tramadol LP 200 mg, a new once-daily,sustained-release formulation, with those of placebo in patients with osteoarthritis of the hip or knee.

METHODS

In this multicenter, double-blind, placebo-controlled, parallel-group study, patients with osteoarthritis of the hip or knee (European League Against Rheumatism criteria) were randomized to receive either tramadol LP 200 mg once daily or placebo for 14 days. The primary efficacy end point was the change from baseline to the end of the study in scores on the Huskisson visual analog scale for pain. Secondary end points were change in the Lequesne functional discomfort index, global efficacy assessed by the patient and the investigator, time to improvement, and use of acetaminophen as rescue analgesic medication. Global tolerability was assessed by both patients and investigators at the end of the study The number and severity of adverse events occurring during the study and for 2 weeks thereafter were also recorded.

RESULTS

Two hundred thirty patients (167 women, 63 men) were evaluable for efficacy and safety Demographic data for the tramadol and placebo groups were as follows: mean (SD) age, 67.1 (7.1) and 66.4 (92) years, respectively; female sex, 72.1% and 73.1%; and mean body weight, 74.7 (13.6) and 74.6 (14.8) kg. All patients were white. The completer analysis included 197 patients (85 tramadol, 112 placebo). Pain was significantly reduced in the tramadol LP group compared with the placebo group on day 7 (P = 0.002) and day 14 (P = 0.010). In the patient's assessment of global efficacy, 77.6% (66) of the tramadol LP group reported improvement by day 14, compared with 59.8% (67) of the placebo group; in the investigator's assessment, the efficacy of tramadol LP was rated very good or good for 612% (52) of patients, compared with 30.4% (34) for placebo. Improvement was reported before day 7 in 882% (75) of patients in the tramadol LP group, compared with 65.2% (73) in the placebo group (P = 0.021); the mean time from the initiation of treatment to reported improvement was 3 days for tramadol LP and 6 days for placebo (P < 0.001). Rates of response (defined as > or =30% pain reduction between days 0 and 14) were 64.7% (55) for tramadol LP and 50.0% (56) for placebo (P = 0.039); no rescue medication was used by 60.0% (51) of the tramadol LP group and 36.6% (41) of the placebo group (P - 0.001). One or more adverse event was reported by 45.0% (50) of the tramadol LP group, compared with 193% (23) of the placebo group (P < 0.001). As would be expected with an opiate agonist such as tramadol, the most common adverse events with this agent involved the gastrointestinal system (nausea, 22.5% [25] of patients; vomiting, 17.1% [19]) and the central nervous system (somnolence, 11.7% [13]).

CONCLUSIONS

In this study, tramadol LP 200 mg was significantly more effective than placebo in alleviating pain in patients with osteoarthritis of the hip or knee. It appeared to be relatively well tolerated for an opioid compound.

Chronic noncancer pain rehabilitation with opioid withdrawal: comparison of treatment outcomes based on opioid use status at admission

OBJECTIVE

To study differences in treatment outcomes between patients with chronic noncancer pain taking vs those not taking maintenance opioids at admission to a pain rehabilitation program.

PATIENTS AND METHODS

A nonrandomized 2-group prepost design was used to compare 356 patients admitted to the Mayo Comprehensive Pain Rehabilitation Center from January 2002 to December 2002 at admission and discharge by opioid status at admission. Measures of pain severity, interference due to pain, perceived life control, affective distress, activity level, depression, and catastrophizing (an exaggerated negative mental set associated with actual or anticipated pain experiences) were used to compare opioid and nonopioid groups. The patients entered a 3-week intensive outpatient multidisciplinary pain rehabilitation program designed to improve adaptation to chronic noncancer pain. The program uses a cognitive-behavioral model and incorporates opioid withdrawal.

RESULTS

More than one third of patients (135/356) were taking opioids daily at admission. At completion of the program, all but 3 of the 135 patients had successfully discontinued opioid treatment. No significant pretreatment differences were found between the opioid and nonopioid group regarding demographics, pain duration, treatment completion, or all outcome variables, including pain severity. Significant improvement was noted at discharge for all outcome variables assessed regardless of opioid status at admission.

CONCLUSION

Patients with symptomatically severe and disabling pain while taking maintenance opioid therapy can experience significant improvement in physical and emotional functioning while participating in a pain rehabilitation program that incorporates opioid withdrawal.

Development of a self-report screening instrument for assessing potential opioid medication misuse in chronic pain patients

This study constituted the first step in the psychometric development of a self-report screening instrument for risk of opioid medication misuse among chronic pain patients. A 26-item instrument, the Pain Medication Questionnaire (PMQ), was constructed based on suspected behavioral correlates of opioid medication misuse, which heretofore have received limited empirical investigation. The PMQ was administered to 184 patients at an interdisciplinary pain treatment center. Reliability coefficients for the PMQ were found to be of moderate but acceptable strength. Construct and concurrent validity were examined through correlation of PMQ scores to measures of substance abuse, physical and psychological functioning, and physicians' risk assessments. To explore high and low cutoff points for misuse risk, subgroups were formed according to the upper and lower thirds of PMQ scores and compared on validity measures. Higher PMQ scores were associated with history of substance abuse, higher levels of psychosocial distress, and poorer functioning. Future psychometric analyses will consider predictive validity and examine shortened versions of the instrument.

Transdermal buprenorphine

Buprenorphine is a low molecular weight, lipophilic, opioid analgesic. Recently, a transdermal matrix patch formulation of buprenorphine has become available in three dosage strengths designed to release buprenorphine at 35, 52.5 and 70 micro g/h over a 72-hour period. At least satisfactory analgesia with minimal requirement for rescue medication (</=0.2 mg/day sublingual buprenorphine) was achieved by 34-50% of patients with chronic pain treated with transdermal buprenorphine 35, 52.5 or 70 micro g/h and 31% of placebo recipients, in one double-blind, placebo-controlled, randomised trial. In one trial involving patients unsuccessfully treated with weak opioids or morphine, 36.6% and 47.5% of buprenorphine 35 micro g/h and 52.5 micro g/h recipients, respectively, experienced at least satisfactory analgesia and received </=0.2 mg/day of sublingual buprenorphine compared with 16.2% of placebo recipients (both p </= 0.032). The requirement for rescue medication was reduced from baseline in >50% of patients treated with transdermal buprenorphine, in two trials. Furthermore, despite the availability of rescue medication to all patients, those receiving transdermal buprenorphine tended to experience greater pain relief, reduced pain intensity and longer pain-free sleep. Transdermal buprenorphine was generally well tolerated. Systemic adverse events were typical of opioid treatment or were attributable to the underlying disease.

Pain management in older adults

Pain is a common complaint of older adults. Persistent pain has a significant negative impact on elderly individuals' sense of well being, physical function, and quality of life. Increasing age and cognitive impairment are risk factors for undertreatment of persistent pain. Safe and effective therapy is available for pain syndromes that commonly affect older adults. Recognition of failure of health providers to appropriately assess and manage persistent pain has led to the recent development and adoption of regulatory guidelines for the implementation of effective pain management programs.

The assessment and management of chronic pain in children

Chronic pain in children and adolescents is frequently misdiagnosed by caregivers. It is not treated until it results in the loss of routine ability and function. Chronic pain is often associated with underlying diseases commonly seen in childhood, including sickle cell disease, malignancy, rheumatologic disorders, inflammatory bowel disease, trauma, and states where there is no identifiable etiology. Chronic pain differs from acute pain in that it serves no useful function. Untreated or under-treated chronic pain will result in the unnecessary suffering of the patient, disruption of family routine, and cohesiveness and restriction of the child's daily activities, thereby increasing long-term disability. Accurate and repeated assessment of chronic pain is required for therapy to be effective. Assessment of chronic pain in children is difficult due to their developing cognitive abilities. The assessment of childhood pain varies with the child's age, type of pain, situation, and prior painful experiences. Assessment tools such as the Varni-Thompson Pediatric Pain Questionnaire and the Visual Analog Scale are helpful for both the patient and physician in helping to identify situations that precipitate pain, to rate the level of pain and determine if therapy has been effective. Documentation of pain assessments and the effectiveness of interventions in the medical record should be included as a routine part of all patient records. Most caregivers have extensive experience in the treatment of acute pain in children but are often not comfortable with the management of complicated and chronic pain states. The therapy for chronic pain in children is multifactorial. It can include agents from multiple classes of pharmacologic agents (nonsteroidal anti-inflammatory drugs, opioids, tricyclic antidepressants, and antineuroleptics) nonconventional therapies (acupuncture and pressure and aromatherapy), as well as herbal and homeopathic remedies.

Benefit-Risk Assessment of Transdermal Fentanyl for the Treatment of Chronic Pain

Transdermal fentanyl is effective and well tolerated for the treatment of chronic pain caused by malignancy and non-malignant conditions when administered according to the manufacturer's recommendations. Compared with oral opioids, the advantages of transdermal fentanyl include a lower incidence and impact of adverse effects (constipation, nausea and vomiting, and daytime drowsiness), a higher degree of patient satisfaction, improved quality of life, improved convenience and compliance resulting from administration every 72 hours, and decreased use of rescue medication. Transdermal fentanyl is a useful analgesic for cancer patients who are unable to swallow or have gastrointestinal problems. Transdermal fentanyl forms a depot within the upper skin layers before entering the microcirculation. Therapeutic blood levels are attained 12-16 hours after patch application and decrease slowly with a half-life of 16-22 hours following removal. Patients with chronic pain should be titrated to adequate relief with short-acting oral or parenteral opioids prior to the initiation of transdermal fentanyl in order to prevent exacerbations of pain or opioid-related adverse effects. Transdermal fentanyl can then be initiated based on the 24-hour opioid requirement once adequate analgesia has been achieved. The prolonged elimination of transdermal fentanyl can become problematic if patients develop opioid-related adverse effects, especially hypoventilation. Adverse effects do not improve immediately after patch removal and may take many hours to resolve. Patients who experience opioid-related toxicity associated with respiratory depression should be treated immediately with an opioid antagonist such as naloxone and closely monitored for at least 24 hours. Because of the short half-life of naloxone, sequential doses or a continuous infusion of the opioid antagonist may be necessary. Transdermal fentanyl should be administered cautiously to patients with pre-existing conditions such as emphysema that may predispose them to the development of hypoventilation. Transdermal fentanyl is indicated only for patients who require continuous opioid administration for the treatment of chronic pain that cannot be managed with other medications. It is contraindicated in the management of acute and postoperative pain, as pain may decrease more rapidly in these circumstances than fentanyl blood levels can be adjusted, leading to the development of life-threatening hypoventilation. Cognitive and physical impairments such as confusion and abnormal co-ordination can occur with transdermal fentanyl. Therefore, patients should be instructed to refrain from driving or operating machinery immediately following the initiation of transdermal fentanyl, or after any dosage increase. Patients may resume such activities once the absence of these potential adverse effects is documented.

The analgesic efficacy of valdecoxib vs. oxycodone/acetaminophen after oral surgery

BACKGROUND

The authors conducted two studies to compare the analgesic efficacy and safety of the cyclooxygenase, or COX, -2-specific inhibitor, valdecoxib, with oxycodone/ acetaminophen in patients who have undergone oral surgery.

METHODS

In total, 205 eligible subjects in Study A and 201 in Study B were randomized to receive a single oral dose of valdecoxib (20 or 40 milligrams), a combination of oxycodone 10 mg/acetaminophen 1,000 mg or placebo. Eligible subjects experienced moderate-to-severe pain within six hours of surgery during which two or more impacted third molars were extracted. Analgesic efficacy was assessed over 24 hours or until the patient required rescue analgesia.

RESULTS

In both studies, subjects receiving either dose of valdecoxib experienced a rapid onset of analgesia and (among those who received valdecoxib 40 mg) a level of pain relief comparable with that of those who received oxycodone/ acetaminophen. Both valdecoxib doses had a significantly longer duration of analgesic effect than did oxycodone/acetaminophen. Pooled safety data demonstrated that each valdecoxib dose had a tolerability profile superior to that of oxycodone/ acetaminophen and similar to that of placebo.

CONCLUSIONS

Orally administered valdecoxib is as rapidly acting and effective as oxycodone/acetaminophen, and it has a superior duration of analgesic effect in patients after oral surgery. Valdecoxib has a tolerability profile superior to that of oxycodone/acetaminophen.

CLINICAL IMPLICATIONS

The current standard of care for alleviating acute pain after oral surgery has rested largely on conventional nonsteroidal anti-inflammatory drugs or opioid/analgesic combination products. The studies reported here suggest that the COX-2-specific inhibitor valdecoxib offers an efficacious and safe alternative to other analgesics used to treat pain after oral surgery.

Rational and targeted pharmacologic treatment of fibromyalgia

Despite disappointing results when subjected to randomized clinical trials, pharmacologic agents remain an important component of FM management. Addressing the main symptoms of pain, disturbed sleep, mood disturbances, fatigue, and associated conditions is essential to improve patient functioning and enhanced quality of life. However, much work remains to design clinical trials which address the complexity of FM, while satisfying evidence based medicine paradigms.

Chronic pain prevalence and analgesic prescribing in a general medical population

In order to better understand the prevalence of chronic pain and the frequency of analgesic use in the U.S. veteran general medical population, a review of 300 randomly selected charts was conducted. This review revealed that 50% of patients suffered from at least one type of chronic pain. A review of the corresponding pharmacy records indicated that approximately 75% of patients with chronic pain were prescribed at least 1 analgesic, and most received 2 or more. While nonsteroidal anti-inflammatory drugs were the most commonly prescribed class of analgesics, 44% of those receiving an analgesic received opioids. Examination of clinic notes revealed that the prescribing physicians documented physical examination infrequently, and commented on a specific opioid treatment plan or follow-up of that plan in a minority of cases. It appears that chronic pain is common among U.S. veterans, and that analgesics, including opioids, are commonly prescribed. Documentation of the efficacy of opioids for treating chronic pain is often scant.