Trends in opioid use for chronic neuropathic pain: a survey of patients pursuing enrollment in clinical trials

Do male and female general practitioners differently prescribe chronic pain drugs to older patients?

OBJECTIVE

The aim of this study was to identify the relationship between general practitioner (GP) gender and prescribing practice of chronic pain drugs in older adults.

DESIGN

Cross-sectional observational study.

SETTING

GPs in private practice throughout France.

SUBJECTS

Two hundred and sixty GPs (80.8% male and 19.2% female) enrolled 1,379 (28.4% male and 71.6% female) noninstitutionalized patients over 65 years of age, suffering from chronic pain.

METHODS

A comparison of prescribing habits between male and female GPs was performed on baseline data with univariate analyses followed by multivariate analyses after taking several confounding factors into account.

RESULTS

No significant differences were found when comparing male and female GPs' prescriptions of World Health Organization step 1, step 2, and step 3 analgesics. Male GPs were more likely than female GPs to prescribe antineuropathic pain drugs (11.3% of patients with male GPs versus 4.8% of patients with female GPs, P = 0.004) and less likely to prescribe symptomatic slow-acting drugs for osteoarthritis (SySADOA) (10.2% of male GPs' patients versus 18.8% of female GPs' patients, P = 0.0003). After adjusting for several confounding factors, male GPs were still more likely to prescribe antineuropathic pain drugs (OR 2.43, 95% CI 1.15-5.14, P = 0.02) and less likely to prescribe symptomatic slow-acting drugs (OR 0.64, 95% CI 0.42-0.97, P = 0.03).

CONCLUSION

Male and female GPs prescribe analgesics in a similar manner. However, male GPs prescribe more antineuropathic pain drugs, but fewer SySADOA.

Effect of pregabalin in the treatment of refractory neck pain: cost and clinical evidence from medical practice in orthopedic surgery and rehabilitation clinics

BACKGROUND

The study aims to prospectively analyze the effect of adding pregabalin upon costs and consequences in the treatment of refractory neck pain under routine medical practice.

METHODS

A secondary analysis was carried out including patients over 18 years, with 6-month chronic neck pain refractory from a prospective, naturalistic, 12-week two-visit study. The analysis compared patients adding pregabalin to its therapy vs. usual care. Severity of pain, healthcare resources utilization, lost workday equivalents (LWDE) because of pain, and related cost-adjusted reductions were assessed.

RESULTS

A total of 312 patients (65.3% women, age 54.2 [12.1] years), 78.2% receiving pregabalin, were analyzed. Adding pregabalin was associated with higher adjusted reduction in pain severity: -3.2 (1.8) points, 55.4% responders (≥50% baseline pain reduction) vs. -2.3 (2.0) and 38.2%, respectively; P<0.001, yielding a higher reduction in mean LWDE: 20.1 (23.1) vs. 8.2 (22.4); P=0.014, which produced significant reductions in the indirect components of cost: €1,041.0 (1,222.8) vs. €457.3 (1,132.1), P=0.028. The costs of pregabalin (€309.8 [193.2] vs. €26.4 [79.6], P<0.001) was offset by higher numerical reductions in the other components of costs, producing similar direct cost reductions in both groups at the end of the study: €66.8 (1,080.8) and €143.5 (1,922.4), respectively; P=0.295.

CONCLUSION

Compared with usual care, the addition of pregabalin to treat refractory neck pain seems to be associated with a higher reduction in pain severity and lost work-days equivalents, which in turn results in a greater reduction of the indirect components of cost while maintaining similar healthcare cost levels despite its higher price.

A cost-consequence analysis of pregabalin versus usual care in the symptomatic treatment of refractory low back pain: sub-analysis of observational trial data from orthopaedic surgery and rehabilitation clinics

BACKGROUND

low back pain is one of the most common reasons for outpatient consultation in both the primary-care and specialized-care settings. However, few studies have explored the effect of pregabalin in this context.

OBJECTIVE

to prospectively analyse the effect of adding pregabalin on costs and consequences in the treatment of refractory low back pain in routine medical practice.

METHODS

a secondary analysis was carried out in patients aged >or=18 years with a 6-month history of chronic refractory low back pain who had participated in a previous prospective, naturalistic, 12-week, two-visit study (RADIO study). The analysis compared patients receiving pregabalin with those receiving usual care. Severity of pain, healthcare resources utilization, lost workday equivalents due to pain, and related cost-adjusted reductions were assessed. The year of costing for all cost data reported in the study was 2007.

RESULTS

data from a total of 683 patients (49.5% women, mean age 55.0 years), 82.6% of whom were receiving pregabalin, were analysed. Pregabalin was associated with a higher covariable-adjusted reduction in severity of pain, i.e. mean (SD) -3.4 (2.0) compared with -2.0 (2.1) points with usual care on a 10-point neuropathic pain questionnaire (p < 0.001), and a 61.6% response rate (defined as >/=50% reduction in pain from baseline) compared with 37.3% with usual care (p < 0.001). This resulted in fewer lost workday equivalents in the pregabalin group versus usual care (27.8 vs 34.6, p = 0.002), which produced more significant adjusted reductions in indirect costs, i.e. mean (SD) -euro961.8 (euro1242.9) compared with -euro625.8 (euro1169.2) with usual care (p = 0.004). The cost of pregabalin, i.e. mean (SD) euro303.8 (euro175.8) compared with euro37.1 (euro97.0) for usual care (p < 0.001), was offset by larger reductions in the other cost components. While the adjusted total costs were substantially reduced in both groups, pregabalin-treated patients showed more significant reductions, i.e. mean (SD) -euro991.5 (euro1702.3) compared with -euro579.3 (euro2410.3) with usual care (p = 0.023).

CONCLUSION

compared with usual care, addition of pregabalin to existing therapy for refractory low back pain was associated with a larger reduction in pain severity and lost workday equivalents. The acquisition cost of pregabalin was offset by a higher reduction in the indirect components of cost, resulting in a significant decrease in total costs.

Patient-reported-outcomes in subjects with painful lumbar or cervical radiculopathy treated with pregabalin: evidence from medical practice in primary care settings

The objective of this study was to evaluate the effect of pregabalin in painful cervical or lumbosacral radiculopathy treated in Primary Care settings under routine clinical practice. An observational, prospective 12-week secondary analysis was carried-out. Male and female above 18 years, naïve to PGB, with refractory chronic pain secondary to cervical/lumbosacral radiculopathy were enrolled. SF-MPQ, Sheehan Disability Inventory, MOS Sleep Scale, Hospital Anxiety and Depression Scale and the EQ-5D were administered. A total of 490 (34%) patients were prescribed PGB-monotherapy, 702 (48%) received PGB add-on, and 159 (11%) were administered non-PGB drugs. After 12 weeks, significant improvements in pain, associated symptoms of anxiety, depression and sleep disturbances, general health; and level of disability were observed in the three groups, being significantly greater in PGB groups. In routine medical practice, monotherapy or add-on pregabalin is associated with substantial pain alleviation and associated symptoms improvements in painful cervical or lumbosacral radiculopathy.

Therapy of chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is still a common and disabling side effect of many chemotherapy agents in use today. Unfortunately, neither prophylactic strategies nor symptomatic treatments have proven useful yet. This review will discuss the diagnosis and evaluation of neuropathy in cancer patients, as well as reviewing the various prophylactic and symptomatic treatments that have been proposed or tried. However, sufficient evidence is lacking to recommend any of these treatments to patients suffering with CIPN. Therefore, the best approach is to treat symptomatically, and to start with broad-spectrum analgesic medications such as non-steroidal anti-inflammatory drugs (NSAIDs). If NSAIDs fail, a reasonable second-line agent in properly selected patients may be an opioid. Unfortunately, even when effective in other types of neuropathic pain, anti-depressants and anticonvulsants have not yet proven effective for treating the symptoms of CIPN.

High-dose morphine for intractable phantom limb pain

Phantom limb pain is difficult to treat as existing therapies have limited effectiveness and what works for one person may not work for another. This makes the fact that research is ongoing and advancing even more important to many people who have this problem. We are reporting a case of intractable phantom limb pain whose pain did not respond to usual line of treatment and only high dose of morphine made the patient totally pain free.

Neuropathic pain: a practical guide for the clinician

Neuropathic pain, caused by various central and peripheral nerve disorders, is especially problematic because of its severity, chronicity and resistance to simple analgesics. The condition affects 2%-3% of the population, is costly to the health care system and is personally devastating to the people who experience it. The diagnosis of neuropathic pain is based primarily on history (e.g., underlying disorder and distinct pain qualities) and the findings on physical examination (e.g., pattern of sensory disturbance); however, several tests may sometimes be helpful. Important pathophysiologic mechanisms include sodium-and calcium-channel upregulation, spinal hyperexcitability, descending facilitation and aberrant sympathetic-somatic nervous system interactions. Treatments are generally palliative and include conservative nonpharmacologic therapies, drugs and more invasive interventions (e.g., spinal cord stimulation). Individualizing treatment requires consideration of the functional impact of the neuropathic pain (e.g., depression, disability) as well as ongoing evaluation, patient education, reassurance and specialty referral. We propose a primary care algorithm for treatments with the most favourable risk-benefit profile, including topical lidocaine, gabapentin, pregabalin, tricyclic antidepressants, mixed serotonin-norepinephrine reuptake inhibitors, tramadol and opioids. The field of neuropathic pain research and treatment is in the early stages of development, with many unmet goals. In coming years, several advances are expected in the basic and clinical sciences of neuropathic pain, which will provide new and improved therapies for patients who continue to experience this disabling condition.

Combination pharmacotherapy for neuropathic pain: current evidence and future directions

Current drugs reduce neuropathic pain and improve mood and quality of life. However, as single agents they are limited by incomplete efficacy and dose-limiting adverse effects. Recent experimental and clinical data support the potential of combination pharmacotherapy for neuropathic pain. Therapeutic benefits may include greater efficacy, lower doses and fewer adverse effects. Due to potential adverse, as well as beneficial, drug interactions, safety and efficacy of specific combinations must be empirically evaluated. Techniques such as isobolographic analysis, response-surface modeling and other model-free tests have been used in order to characterize analgesic interactions as antagonistic, additive or synergistic. Whether synergistic or not, a clinically useful combination could simply have additive or even subadditive analgesia, provided that there is less additivity for side effects. Despite widespread clinical use, there are surprisingly few published observations on combination therapy for neuropathic pain. This review discusses future directions and proposes research strategies aimed at bridging current knowledge gaps, including safety, compliance and cost-effectiveness; discovering optimal drug combinations and dose ratios; comparing concurrent with sequential combination therapy; and combining more than two drugs. Continued close integration of basic and clinical sciences is crucial in further harnessing the potential of combination pharmacotherapy in neuropathic pain.

Sex-related psychological predictors of baseline pain perception and analgesic responses to pentazocine

Sex differences in pain perception and analgesic responses have garnered increasing attention in recent years. We examined the association of psychological factors to baseline pain perception and pentazocine analgesia among 49 healthy women and 39 men. Subjects completed psychological questionnaires measuring positive and negative affect as well as catastrophizing. Subsequently, responses to experimental pain were assessed before and after double-blind administration of intravenous pentazocine (0.5mg/kg). In correlational analyses, positive affect predicted lower pain sensitivity among men but not women. Negative affect predicted lower baseline pain tolerances among both sexes but predicted poorer analgesia only among men. Catastrophizing was associated with greater pain sensitivity and less analgesia more consistently in men than women. Regression models revealed that positive affect predicted lower overall pain sensitivity and catastrophizing predicted poorer overall analgesic responses among men, while no significant predictors of overall pain or analgesia emerged for women. Moreover, positive affect and catastrophizing were negatively and positively correlated, respectively, with side effects from the medication, but only among men. These findings indicate sex-dependent associations of psychological factors with baseline pain perception, analgesic responses, and medication side effects.

Pharmacologic management of neuropathic pain

The mechanisms underlying the pathogenesis of neuropathic pain are complex but are gradually coming to light. Agents that have been found effective in a variety of neuropathic pain conditions include drugs that act to modulate (a) sodium or calcium channels, (b) N-methyl-D-aspartate receptors, (c) norepinephrine or serotonin reuptake, (d) opioid receptors, and (e) other cellular processes. Clinical trials have primarily evaluated these treatments for postherpetic neuralgia and painful diabetic neuropathy, the two most common types of neuropathic pain. Nonetheless, the identification of effective treatment regimens remains challenging, often because multiple mechanisms may be operating in a given patient giving rise to the same symptom. Alternatively, a single mechanism may be responsible for multiple symptoms. Currently available diagnostic tools are inadequate to determine the best treatment using a mechanism-based model. Clinically, drug treatment of neuropathic pain is often a matter of treatment trials. This article presents a summary of available clinical information on first-line and lesser-known treatments for neuropathic pain.

Manipulating presence influences the magnitude of virtual reality analgesia

Excessive pain during medical procedures performed in unanesthetized patients is frequently reported, but can be reduced with virtual reality (VR) distraction. Increasing the person's illusion of going into the virtual world may increase how effectively VR distracts pain. Healthy volunteers aged 18-20 years participated in a double-blind between-groups design. Each subject received a brief baseline thermal pain stimulus, and the same stimulus again minutes later with either a Low Tech or a High Tech VR distraction. Each subject provided subjective 0-10 ratings of cognitive, sensory and affective components of pain, and rated their illusion of going inside the virtual world. Subjects in the High Tech VR group reported a stronger illusion of going into the virtual world (VR presence) than subjects in the Low Tech VR group, (4.2 vs. 2.5, respectively, P = 0.009) and more pain reduction (reduction of worst pain is 3.1 for High Tech VR vs. 0.7 for Low Tech VR, P < 0.001). Across groups, the amount of pain reduction was positively and significantly correlated with VR presence levels reported by subjects ( r = 0.48 for 'worst pain', P < 0.005).