Gabapentin as part of a multimodal pain protocol for selective dorsal rhizotomy does not impact percentage of rootlets transected

PURPOSE

We aim to determine whether preoperatively initiated gabapentin for pain control impacts the percentage of rootlets cut during monitored, limited laminectomy selective dorsal rhizotomy (SDR) procedure.

METHODS

This retrospective cohort study includes participants with cerebral palsy who had SDR for treatment of spasticity between 2010 and 2019 at a single-institution tertiary care center. One-level laminectomy SDR aimed to evaluate the cauda equina roots from levels L2-S1 with EMG monitoring. Gabapentin titration began 3 weeks prior to SDR. Data was analyzed using simple linear regression. Thirty-one individuals met inclusion criteria. Mean age was 7 years, 4 months. Eighteen participants (58%) identified as male, 12 (39%) female, and one (3%) non-binary. Thirty (97%) had bilateral CP. Sixteen (52%) were GMFCS II, four (13%) GMFCS III, five (16%) GMFCS IV, and six (19%) GMFCS V.

RESULTS

Mean percentage of rootlets transected was 50.75% (SD 6.00, range 36.36-60.87). There was no relationship between the dose of gabapentin at time of SDR and percentage of rootlets cut with a linear regression slope of - 0.090 and an R2 of 0.012 (P = 0.56).

CONCLUSION

Results indicate that preoperative initiation of gabapentin did not impact the percentage of rootlets transected. Thus, gabapentin can be initiated prior to SDR at moderate dosages without impacting SDR surgical outcomes.

COVID-19 impact and response by Canadian pain clinics: A national survey of adult pain clinics

Background: As the result of public health authority responses to the COVID-19 pandemic, pain clinics have had to cease providing in-person appointments to reduce contact between patients and staff. Over the past decade, Canadians living with chronic pain have faced long waiting times for care within multidisciplinary pain clinics. We are concerned that ceasing in-person pain services exacerbates the daily hardships already faced by Canadians living with chronic pain.

Aims: The aim of this study was to evaluate the impact of the COVID-19 pandemic on Canadian pain clinics, their responses, and changes to clinic practices that might be maintained when the pandemic is over.

Methods: A survey of Canadian adult multidisciplinary pain clinics was conducted to determine impacts on medical and allied health care services and the strategies used to deliver care to patients during the COVID-19 pandemic.

Results: Responses received from 17 adult pain clinics across Canada showed that adult multidisciplinary pain clinics had to cease or significantly reduce in-person patient contacts during the COVID-19 pandemic and responded by offering telehealth options. Despite their efforts, patients are waiting longer and have lost access to usual care. Increased levels of pain, stress, and medication use, particularly opioids and cannabinoids, were reported.

Conclusions: Access to adaptable and innovative technologies, such as telehealth, can assist in the care of the one in five Canadians living with chronic pain during times of crises and must be included as a vital component of a comprehensive Canadian pain strategy.

Pediatric telerehabilitation medicine: Making your virtual visits efficient, effective and fun

The COVID-19 pandemic has accelerated many changes in medicine including the transition from providing care in person to providing care via technology enabled telemedicine. The benefits of telemedicine visits with a Pediatric Rehabilitation Medicine (PRM) provider, also known as telerehabilitation medicine visits, are numerous. Telerehabilitation medicine provides an opportunity to deliver timely, patient and family-centric rehabilitation care while maintaining physical distance and reducing potential COVID-19 exposure for our patients, their caregivers and medical providers. Telerehabilitation medicine also allows for access to PRM care in rural areas or areas without medical specialty, virtual in-home equipment evaluation, and reduced travel burden. Because of these and many other benefits, telerehabilitation medicine will likely become part of our ongoing model of care if barriers to telemedicine continue to be lowered or removed. This paper is intended to establish a foundation for pediatric telerehabilitation medicine visit efficiency and effectiveness in our current environment and into the future.

The Assessment and Prevalence of Affective Disorders in Advanced Cancer

The assessment of depression in patients with advanced cancer presents a difficult clinical challenge. Reported prevalence rates of depression in cancer patients range from 3.7% to 58%. Studies using structured diagnostic interviews and clearly defined diagnostic criteria are presented. The current literature suggests that among hospitalized cancer patients with significant levels of physical impairment at least 25% suffer from clinically important depression. Risk of suicide and recent literature regarding early wish to die are also discussed.

The utility of universal urinary drug screening in chronic pain management

BACKGROUND

A recent systematic review found few studies that assessed the value of urinary drug screening (UDS) in the management of chronic pain. The Pain Management Unit in Halifax, Nova Scotia, has recently implemented tandem mass spectrometry (TMS) UDS for all new patients.

AIMS

To study the prevalence of unexpected TMS UDS results at a hospital-based chronic pain center, to assess which drugs are most likely to contribute to an unexpected result and to assess the clinical utilization of unexpected results by pain physicians.

METHODS

From June 2014 to June 2016, a total of 664 patients with chronic non-cancer pain (CNCP) were seen for initial consult. Charts were reviewed and used to create a database containing sex, age, UDS result, physician, and medication/illicit drug history. For all unexpected UDS results, an interview was conducted with the treating physician to determine its clinical implications.

RESULTS

For the general pain specialists, the overall percentage of patients with an unexpected UDS result was 16.67%. Excluding codeine, at most 4.47% of patients tested unexpectedly positive for a strong opioid. Although eight out of nine physicians found UDS helpful in general, only 29.58% of unexpected results were helpful in the management of their patients and directly influenced their care.

CONCLUSIONS

The prevalence of an unexpected UDS result in patients with CNCP is significant. Most physicians agree that UDS is helpful but in only a limited number of cases did the unexpected result provide helpful information that significantly influenced patient care.

A prospective observational study of problematic oral cannabinoid use

BACKGROUND

Despite evidence supporting the benefits of cannabinoids for symptom control across a wide range of medical conditions, concerns have been raised regarding the potential misuse and/or problematic use of cannabinoids (CBs).

OBJECTIVE

The first objective of this study was to examine the incidence of problematic prescription cannabinoid use (PPCBU) over a 12-month period among patients initiating cannabinoid therapy. The second objective was to examine the factors associated with PPCBU. A total of 265 patients who were prescribed oral cannabinoid therapy as part of usual medical practice were enrolled into this prospective observational study. Patients first completed a series of baseline questionnaires assessing demographic, clinical, and substance use variables. Three measures designed to assess PPCBU were then administered at 3, 6, and 12 months after initiation of cannabinoid therapy.

RESULTS

At each of the follow-up assessment time points, a significantly greater number of patients scored below (vs above) cutoff scores on the three main PPCBU outcomes (all p's < .001). At any follow-up time point, a maximum of roughly 25% of patients demonstrated PPCBU. Heightened odds of PPCBU were observed among patients with a history of psychiatric problems, tobacco smokers, and recreational cannabis users (all p's < .05). Results indicated that past-year substance abuse, assessed using the DAST-20, was the strongest predictor of PPCBU (p < .005).

CONCLUSION

Findings from the present study could have implications for clinicians considering the use of cannabinoids for the management of patients with medical conditions. Although results indicated that the majority of patients included in this study did not reach cutoff scores on the three main PPCBU outcomes, our findings suggest that PPCBU should be routinely assessed and monitored over the course of cannabinoid therapy, particularly among patients with a history of psychiatric or substance use problems.

Qigong and Fibromyalgia circa 2017

Qigong is an internal art practice with a long history in China. It is currently characterized as meditative movement (or as movement-based embodied contemplative practice), but is also considered as complementary and alternative exercise or mind–body therapy. There are now six controlled trials and nine other reports on the effects of qigong in fibromyalgia. Outcomes are related to amount of practice so it is important to consider this factor in overview analyses. If one considers the 4 trials (201 subjects) that involve diligent practice (30–45 min daily, 6–8 weeks), there are consistent benefits in pain, sleep, impact, and physical and mental function following the regimen, with benefits maintained at 4–6 months. Effect sizes are consistently in the large range. There are also reports of even more extensive practice of qigong for 1–3 years, even up to a decade, indicating marked benefits in other health areas beyond core domains for fibromyalgia. While the latter reports involve a limited number of subjects and represent a self-selected population, the marked health benefits that occur are noteworthy. Qigong merits further study as a complementary practice for those with fibromyalgia. Current treatment guidelines do not consider amount of practice, and usually make indeterminate recommendations.

Pain expectations in neuropathic pain: Is it best to be optimistic?

BACKGROUND

Pain expectancy may be an important variable that has been found to influence the effectiveness of treatments for pain. Much of the literature supports a self-fulfilment perspective where expectations for pain relief predict the actual pain experienced. However, in conditions such as neuropathic pain (NeP) where pain relief is difficult to attain, expectations for pain relief could be unrealistic. The objective of this study was to investigate the relationship between realistic/unrealistic expectations and 6-month, post-treatment outcomes.

METHODS

We performed a retrospective analysis of a large cohort of patients with NeP (n = 789) attending tertiary care centres to determine the association between unrealistic (both positive and negative) and realistic expectations with outcomes after multidisciplinary treatment. An expectation variable with three categories was calculated: realistic expectations were those whose expected reduction in pain was similar to the observed mean group reduction in pain, while optimistic and pessimistic expectations were those who over- or under-estimated the expected response to treatment, respectively. The association between baseline realistic/unrealistic expectations and 6-month pain-related disability, catastrophizing and psychological distress was assessed.

RESULTS

Univariable analyses suggested that realistic expectations were associated with lower levels of disability, catastrophizing and psychological distress, compared to unrealistic expectations. However, after adjustment for baseline symptom severity, multivariable analysis revealed that patients with optimistic expectations had lower levels of disability, than those with realistic expectations. Those with pessimistic expectations had higher levels of catastrophizing and psychological distress at follow-up.

CONCLUSIONS

These findings are largely congruent with the self-fulfilment perspective to expectations.

SIGNIFICANCE

This study defined realistic pain expectations with patient data. Examining the relationship between expectations between pain and disability in a large cohort of patients with neuropathic pain.

Cannabinoids in the management of chronic pain: a front line clinical perspective

Chronic pain is an escalating public health problem. Currently available treatments are inadequate to control chronic pain conditions, and there is a critical need for novel treatments. Over a half century of elegant preclinical research has identified the presence of a sophisticated endocannabinoid system that is part of our natural pain and immune defense network. Convergent work has supported the significant potential to exploit this system to decrease pain and inflammation. Although the clinical research remains in its infancy, recent systematic reviews have found that 25 of 30 randomized controlled trials have demonstrated a significant analgesic effect. The authors concluded that cannabinoids currently available for clinical use demonstrate a modest analgesic effect and are safe for the management of chronic pain. There is a critical need for more translational research so that the excellent work of Dr. Itai Bab and our basic science colleagues around the world can move forward in providing novel cannabinoid-based medicines. This should include more potent analgesics that are limited in side effects with several routes of delivery. Our patients deserve additional agents for pain control with a novel mechanism of action, and cannabinoids are the new frontier.

The Predictive Link between Matrix and Metastasis

Cancer spread (metastasis) is responsible for 90% of cancer-related fatalities. Informing patient treatment to prevent metastasis, or kill all cancer cells in a patient's body before it becomes metastatic is extremely powerful. However, aggressive treatment for all non-metastatic patients is detrimental, both for quality of life concerns, and the risk of kidney or liver-related toxicity. Knowing when and where a patient has metastatic risk could revolutionize patient treatment and care. In this review, we attempt to summarize the key work of engineers and quantitative biologists in developing strategies and model systems to predict metastasis, with a particular focus on cell interactions with the extracellular matrix (ECM), as a tool to predict metastatic risk and tropism.

Exploring the lived experience of adults using prescription opioids to manage chronic noncancer pain

BACKGROUND

Chronic noncancer pain (CNCP) and prescription opioid use is a highly complex and growing health care issue in Canada. Many quantitative research studies have investigated the effectiveness of opioids for chronic pain; however, gaps remain in the literature regarding the personal experience of using opioids and their impact on those experiencing CNCP.

OBJECTIVE

To explore the lived experience of adults using prescription opioids to manage CNCP, focusing on how opioid medication affected their daily lives.

METHODS

In-depth qualitative interviews were conducted with nine adults between 40 and 68 years of age who were using prescription opioids daily for CNCP. Interviews were audiorecorded and transcribed, and subsequently analyzed using interpretive phenomenological analysis.

RESULTS

Six major themes identified positive and negative aspects of opioid use associated with social, physical, emotional and psychological dimensions of pain management. These themes included the process of decision making, and physical and psychosocial consequences of using opioids including pharmacological side effects, feeling stigmatized, guilt, fears, ambivalence, self-protection and acceptance.

CONCLUSION

Although there were many negative aspects to using opioids daily, the positive effects outweighed the negative for most participants and most of the negative aspects were socioculturally induced rather than caused by the drug itself. The present study highlighted the complexities involved in using prescription opioids daily for management of CNCP for individuals living with pain.

Guidelines for the use of cannabinoid compounds in chronic pain

OBJECTIVE

To provide clinicians with guidelines for the use of cannabinoid compounds in the treatment of chronic pain.

METHODS

Publications indexed from 1990 to 2005 in the National Library of Medicine Index Medicus were searched through PubMed. A consensus concerning these guidelines was achieved by the authors through review and discussion.

RESULTS

There are few clinical trials, case reports or case series concerning the use of cannabinoid compounds in the treatment of chronic pain. There are no randomized clinical trials examining the use of herbal cannabis in the treatment of chronic pain.

CONCLUSIONS

A practical approach to the treatment of chronic pain with cannabinoid compounds is presented. Specific suggestions about the off-label dosing of nabilone (Cesamet, Valeant Canada limitee/Limited) and dronabinol (Marinol, Solvay Pharma Inc, Canada) in the treatment of chronic pain are provided.

Preclinical science regarding cannabinoids as analgesics: an overview

Modern pharmacology of cannabinoids began in 1964 with the isolation and partial synthesis of delta-9-tetrahydrocannabinol, the main psycho-active agent in herbal cannabis. Since then, potent antinociceptive and antihyperalgesic effects of cannabinoid agonists in animal models of acute and chronic pain; the presence of cannabinoid receptors in pain-processing areas of the brain, spinal cord and periphery; and evidence supporting endogenous modulation of pain systems by cannabinoids has provided support that cannabinoids exhibit significant potential as analgesics. The present article presents an overview of the preclinical science.

A double-blind, placebo-controlled, crossover pilot trial with extension using an oral mucosal cannabinoid extract for treatment of chemotherapy-induced neuropathic pain

CONTEXT

Neuropathic pain caused by chemotherapy limits dosing and duration of potentially life-saving anti-cancer treatment and impairs quality of life. Chemotherapeutic neuropathy responds poorly to conventional treatments, and there is an urgent medical need for new treatments. Recent preclinical studies demonstrate that cannabinoid agonists suppress established chemotherapy-evoked neuropathy.

OBJECTIVES

This was a pilot trial to begin to investigate a currently available cannabinoid agent, nabiximols (oral mucosal spray containing cannabinoids), in the treatment of chemotherapy-induced neuropathic pain.

METHODS

A randomized, placebo-controlled crossover pilot study was done in 16 patients with established chemotherapy-induced neuropathic pain. A 0-10 point numeric rating scale for pain intensity (NRS-PI) was used as the primary outcome measure.

RESULTS

When examining the whole group, there was no statistically significant difference between the treatment and the placebo groups on the NRS-PI. A responder analysis demonstrated that there were five participants who reported a two-point or greater reduction in pain that trended toward statistical significance and the number needed to treat was five.

CONCLUSION

Chemotherapy-induced neuropathic pain is particularly resistant to currently available treatments. This pilot trial found a number needed to treat of five and an average decrease of 2.6 on an 11-point NRS-PI in five "responders" (as compared with a decrease of 0.6 with placebo) and supports that it is worthwhile to study nabiximols in a full randomized, placebo-controlled trial of chemotherapy-induced neuropathic pain.

Cannabinoids for treatment of chronic non-cancer pain; a systematic review of randomized trials

Effective therapeutic options for patients living with chronic pain are limited. The pain relieving effect of cannabinoids remains unclear. A systematic review of randomized controlled trials (RCTs) examining cannabinoids in the treatment of chronic non-cancer pain was conducted according to the PRISMA statement update on the QUORUM guidelines for reporting systematic reviews that evaluate health care interventions. Cannabinoids studied included smoked cannabis, oromucosal extracts of cannabis based medicine, nabilone, dronabinol and a novel THC analogue. Chronic non-cancer pain conditions included neuropathic pain, fibromyalgia, rheumatoid arthritis, and mixed chronic pain. Overall the quality of trials was excellent. Fifteen of the eighteen trials that met the inclusion criteria demonstrated a significant analgesic effect of cannabinoid as compared with placebo and several reported significant improvements in sleep. There were no serious adverse effects. Adverse effects most commonly reported were generally well tolerated, mild to moderate in severity and led to withdrawal from the studies in only a few cases. Overall there is evidence that cannabinoids are safe and modestly effective in neuropathic pain with preliminary evidence of efficacy in fibromyalgia and rheumatoid arthritis. The context of the need for additional treatments for chronic pain is reviewed. Further large studies of longer duration examining specific cannabinoids in homogeneous populations are required.

Understanding specific effects of prenatal alcohol exposure on brain structure in young adults

Prenatal alcohol exposure (PAE) is associated with various adverse effects on human brain and behavior. Recently, neuroimaging studies have begun to identify PAE effects on specific brain structures. Investigation of such specific PAE effects is important for understanding the teratogenic mechanism of PAE on human brain, which is critical for differentiating PAE from other disorders. In this structural MRI study with young adults, PAE effects on the volumes of automatically segmented cortical and subcortical regions of interest (ROIs) were evaluated both through a group difference approach and a parametric approach. In the group difference approach (comparing among two PAE and a control groups), a disproportionate PAE effect was found in several occipital and temporal regions. This result is inconsistent with previous studies with child samples. Moreover, a gender difference in PAE effect was shown in some cortical ROIs. These findings suggest that sampling and gender may be important factors for interpreting specific PAE effects on human brain. With the parametric approach, it was demonstrated that the higher the PAE level, the smaller the entire brain, the lower the IQ. Several cortical and subcortical ROIs also exhibited a negative correlation between the PAE level and ROI volume. Furthermore, our data showed that the PAE effect on the brain could not be interpreted by the PAE effect on general physical growth until the young adult age. This study provides valuable insight into specific effects of PAE on human brain and suggests important implications for future studies in this field.

The Canadian STOP-PAIN project - Part 2: What is the cost of pain for patients on waitlists of multidisciplinary pain treatment facilities?

PURPOSE

The Canadian STOP-PAIN Project was designed to document the human and economic burden of chronic pain in individuals on waitlists of Multidisciplinary Pain Treatment Facilities (MPTF). This paper describes the societal costs of their pain.

METHODS

A subgroup of 370 patients was selected randomly from The Canadian STOP-PAIN Project. Participants completed a self-administered costing tool (the Ambulatory and Home Care Record) on a daily basis for three months. They provided information about publicly financed resources, such as health care professional consultations and diagnostic tests as well as privately financed costs, including out-of-pocket expenditures and time devoted to seeking, receiving, and providing care. To determine the cost of care, resources were valued using various costing methods, and multivariate linear regression was used to predict total cost.

RESULTS

Overall, the median monthly cost of care was $1,462 (CDN) per study participant. Ninety-five percent of the total expenditures were privately financed. The final regression model consisted of the following determinants: educational level, employment status, province, pain duration, depression, and health-related quality of life. This model accounted for 35% of the variance in total expenditure (P < 0.001).

CONCLUSION

The economic burden of chronic pain is substantial in patients on waitlists of MPTFs. Consequently, it is essential to consider this burden when making decisions regarding resource allocation and waitlist assignment for a MPTF. Resource allocation decision-making should include the economic implications of having patients wait for an assessment and for care.

Compound heterozygosity in sodium channel Nav1.7 in a family with hereditary erythermalgia

Hereditary erythermalgia is a painful and debilitating genetic disorder associated with mutations in voltage-gated sodium channel Nav1.7. We have previously reported a Canadian family segregating erythermalgia consistently with a dominant genetic etiology. Molecular analysis of the proband from the family detected two different missense mutations in Nav1.7. In the present study we have performed a long-term follow-up clinical study of disease progression in three affected family members. A more extensive molecular study has also been completed, analyzing the segregation of the two missense variants in the family. The two variants (P610T, L858F) segregate independently with respect to clinical presentation. Detailed genotype/phenotype correlation suggests that one of the two variants (L858F) is causal for erythermalgia. The second variant (P610T) may modify the phenotype in the proband. This is the second reported study of potential compound heterozygosity for coding polymorphisms in Nav1.7, the first being in a patient with paroxysmal extreme pain disorder.

A systematic review of the effect of waiting for treatment for chronic pain

In many countries timely access to care is a growing problem. As medical costs escalate health care resources must be prioritized. In this context there is an increasing need for benchmarks and best practices in wait-time management. The Canadian Pain Society struck a Task Force in December 2005 to identify benchmarks for acceptable wait-times for treatment of chronic pain. As part of the mandate a systematic review of the literature regarding the relationship between waiting times, health status and health outcomes for patients awaiting treatment for chronic pain was undertaken. Twenty-four studies met the inclusion criteria for the review. The current review supports that patients experience a significant deterioration in health related quality of life and psychological well being while waiting for treatment for chronic pain during the 6 months from the time of referral to treatment. It is unknown at what point this deterioration begins as results from the 14 trials involving wait-times of 10 weeks or less yielded mixed results with wait-times amounting to as little as 5 weeks, associated with deterioration. It was concluded that wait-times for chronic pain treatment of 6 months or longer are medically unacceptable. Further study is necessary to determine at what stage the deterioration begins from the onset of pain to treatment and the impact of waiting on treatment outcomes. Most important is the need to improve access to appropriate care for patients with chronic pain, an escalating public health care problem with significant human and economic costs.

Waiting for treatment for chronic pain - a survey of existing benchmarks: toward establishing evidence-based benchmarks for medically acceptable waiting times

As medical costs escalate, health care resources must be prioritized. In this context, there is an increasing need for benchmarks and best practices in wait time management. In December 2005, the Canadian Pain Society struck a Task Force to identify benchmarks for acceptable wait times for treatment of chronic pain. The task force mandate included a systematic review and survey to identify national or international wait time benchmarks for chronic pain, proposed or in use, along with a review of the evidence upon which they are based. An extensive systematic review of the literature and a survey of International Association for the Study of Pain Chapter Presidents and key informants has identified that there are no established benchmarks or guidelines for acceptable wait times for the treatment of chronic pain in use in the world. In countries with generic guidelines or wait time standards that apply to all outpatient clinics, there have been significant challenges faced by pain clinics in meeting the established targets. Important next steps are to ensure appropriate additional research and the establishment of international benchmarks or guidelines for acceptable wait times for the treatment of chronic pain. This will facilitate advocacy for improved access to appropriate care for people suffering from chronic pain around the world.

A case series of patients using medicinal marihuana for management of chronic pain under the Canadian Marihuana Medical Access Regulations

The Canadian Marihuana Medical Access Regulations (MMAR) program allows Health Canada to grant access to marihuana for medical use to those who are suffering from grave and debilitating illnesses. This is a report on a case series of 30 patients followed at a tertiary care pain management center in Nova Scotia who have used medicinal marihuana for 1-5 years under the MMAR program. Patients completed a follow-up questionnaire containing demographic and dosing information, a series of 11-point numerical symptom relief rating scales, a side effect checklist, and a subjective measure of improvement in function. Doses of marihuana ranged from less than 1 to 5g per day via the smoked or oral route of administration. Ninety-three percent of patients reported moderate or greater pain relief. Side effects were reported by 76% of patients, the most common of which were increased appetite and a sense of well-being, weight gain, and slowed thoughts. Limitations of the study include self-selection bias, small size, and lack of a control group. The need for further study using controlled trials is discussed along with an overview of the MMAR program.

The pharmacotherapy of chronic pain: a review

The past two decades have contributed a large body of preclinical work that has assisted in our understanding of the underlying pathophysiological mechanisms that cause chronic pain. In this context, it has been recognized that effective treatment of pain is a priority and that treatment often involves the use of one or a combination of agents with analgesic action. The current review presents an evidence-based approach to the pharmacotherapy of chronic pain. Medline searches were done for all agents used as conventional treatment in chronic pain. Published papers up to June 2005 were included. The search strategy included randomized, controlled trials, and where available, systematic reviews and meta-analyses. Further references were found in reference sections of papers located using the above search strategy. Agents for which there were no controlled trials supporting efficacy in treatment of chronic pain were not included in the present review, except in cases where preclinical science was compelling, or where initial human work has been positive and where it was thought the reader would be interested in the scientific evidence to date.

A review of the use of methadone for the treatment of chronic noncancer pain

Methadone, although having been available for approximately half a century, is now receiving increasing attention in the management of chronic pain. This is due to recent research showing that methadone exhibits at least three different mechanisms of action including potent opioid agonism, N-methyl-D-aspartate antagonism and monoaminergic effects. This, along with methadone's excellent oral and rectal absorption, high bioavailability, long duration of action and low cost, make it a very attractive option for the treatment of chronic pain. The disadvantages of significant interindividual variation in pharmacokinetics, graduated dose equivalency ratios based on prerotation opioid dose when switching from another opioid, and the requirement for special exemption for prescribing methadone make it more complicated to use. The present review is intended to educate physicians interested in adding methadone to their armamentarium for assisting patients with moderate to severe pain.

Topical 2% amitriptyline and 1% ketamine in neuropathic pain syndromes: a randomized, double-blind, placebo-controlled trial

BACKGROUND

A double-blind, randomized, placebo-controlled 3-week study evaluated the efficacy of topical 2% amitriptyline, 1% ketamine, and a combination of both in treating patients with neuropathic pain.

METHODS

Ninety-two patients with diabetic neuropathy, postherpetic neuralgia, or postsurgical/posttraumatic neuropathic pain with allodynia, hyperalgesia, or pinprick hypesthesia were randomly assigned to receive one of four creams (placebo, 2% amitriptyline, 1% ketamine, or 2% amitriptyline-1% ketamine combined). The primary outcome measure was change in average daily pain intensity (baseline week vs. final week) using an 11-point numerical pain rating scale. Secondary outcomes included the McGill Pain Questionnaire, measures of allodynia and hyperalgesia, and patient satisfaction.

RESULTS

A reduction in pain scores of 1.1-1.5 units was observed in all groups, and there was no difference between groups. Blood concentrations revealed no significant systemic absorption. Minimal side effects were encountered.

CONCLUSION

This randomized, placebo-controlled trial examining topical 2% amitriptyline, 1% ketamine, and a combination in the treatment of neuropathic pain revealed no difference between groups. Optimization of doses may be required, because another study has revealed that higher concentrations of these agents combined do produce significant analgesia.

Dimensions of catastrophic thinking associated with pain experience and disability in patients with neuropathic pain conditions

The objective of the present study was to examine the relative contributions of different dimensions of catastrophic thinking (i.e. rumination, magnification, helplessness) to the pain experience and disability associated with neuropathic pain. Eighty patients with diabetic neuropathy, post-herpetic neuralgia, post-surgical or post-traumatic neuropathic pain who had volunteered for participation in a clinical trial formed the basis of the present analyses. Spontaneous pain was assessed with the sensory and affective subscales of the McGill Pain Questionnaire. Pinprick hyperalgesia and dynamic tactile allodynia were used as measures of evoked pain. Consistent with previous research, individuals who scored higher on a measure of catastrophic thinking (Pain Catastrophizing Scale; PCS) also rated their pain as more intense, and rated themselves to be more disabled due to their pain. Follow up analyses revealed that the PCS was significantly correlated with the affective subscale of the MPQ but not with the sensory subscale. The helplessness subscale of the PCS was the only dimension of catastrophizing to contribute significant unique variance to the prediction of pain. The PCS was not significantly correlated with measures of evoked pain. Catastrophizing predicted pain-related disability over and above the variance accounted for by pain severity. The findings are discussed in terms of mechanisms linking catastrophic thinking to pain experience. Treatment implications are addressed.

A Triage Approach to Managing a Two Year Wait-List in a Chronic Pain Program

OBJECTIVE: Individuals with chronic pain referred to specialist chronic pain management programs frequently wait months to years for assessment and care. In the authors' pain management program, approximately 600 patients are on the waiting list. An innovative recommendation program to encourage and educate referring physicians to continue active care of pain during this waiting period was developed.

METHODS: All referrals to the Queen Elizabeth II Health Sciences Centre's Pain Management Unit for a one-year period were reviewed and triaged as either 'regular waiting list' or 'fast track'. Patients in the fast track group were seen within four months and required limited interventions or were urgent in nature. The regular waiting list group waited up to 27 months for assessment and development of a treatment plan. Treatment recommendations were faxed to the referring physician. A follow-up questionnaire was sent to each physician to assess whether these treatment recommendations were useful.

RESULTS: Recommendations were faxed for 297 patients. One hundred forty-nine physicians returned the follow-up questionnaire. Ninety-five physicians used the recommendations and 68 patients followed the recommendations. Seventy-nine physicians felt that the recommendations were helpful to them in their care of the patient. For 39 patients, the recommendations were helpful. The most frequently used recommendations were those on medications (eg, tricylic antidepressants, anticonvulsants, nonsteroidal anti-inflammatory drugs and controlled-release opioids). Other modalities included participation in an interdisciplinary group program and physiotherapy.

CONCLUSIONS: A triage review process with recommendations faxed to referring physicians was developed and put into action for one year. The recommendations were used by 32% of the physicians (64% of responding physicians). Fifty-three per cent of responding physicians felt that the recommendations were helpful in the care of their patient. This process led to a benefit in care, as perceived by the physician, in 26% of patients (of physicians who returned the questionnaire [13% of all patients]) on the waiting list for a tertiary care pain management unit.

Patterns of cannabis use among patients with multiple sclerosis

To estimate the patterns and prevalence of cannabis use among patients with multiple sclerosis (MS), 220 patients were surveyed in Halifax, Nova Scotia. Seventy-two subjects (36%) reported ever having used cannabis for any purpose; 29 respondents (14%) reported continuing use of cannabis for symptom treatment. Medical cannabis use was associated with male gender, tobacco use, and recreational cannabis use. The symptoms reported by medical cannabis users to be most effectively relieved were stress, sleep, mood, stiffness/spasm, and pain.

A pilot study examining topical amitriptyline, ketamine, and a combination of both in the treatment of neuropathic pain

OBJECTIVE

The involvement of ongoing peripheral activity in the generation of nociceptive input in neuropathic pain suggests that topical drug delivery may be useful as a treatment strategy. This is a pilot study providing initial information regarding the use of novel topical preparations containing amitriptyline (AMI), ketamine (KET), and a combination of both in the treatment of neuropathic pain.

METHODS

The study design included a 2 day randomized, double blind, placebo controlled, 4 way cross-over trial of all treatments, followed by an open label treatment phase using the combination cream for 7 days. Twenty volunteers with chronic neuropathic pain were randomly assigned to treatment order and applied 5 mls of each topical treatment (1% AMI, 0.5% KET, combination AMI 1%/KET 0.5%, and placebo) for 2 days. Measures of pain at the end of each block included the short form McGill Pain Questionnaire (MPQ) and visual analog scales (VAS) for present pain intensity and pain relief. Eleven subjects who judged subjective improvement from any treatment in the initial trial entered the open-label trial and used the combination cream for 7 days. Pain levels were recorded daily using the same measures. Blood levels for amitriptyline and ketamine were performed at 7 days to determine whether systemic absorption had occurred.

RESULTS

There was no statistically significant difference from placebo after 2 days for any treatment during the double blind component of the trial. In the 11 subjects who used the combination cream, there was a statistically significant effect, with subjects reporting significantly greater analgesia by days 3 to 7 according to measures of pain and pain relief. Blood levels revealed that there was no significant systemic absorption of amitriptyline or ketamine. Only 2 subjects experienced side effects; these were minor and did not lead to discontinuation of the cream.

CONCLUSION

This pilot study demonstrated a lack of effect for all treatments in the 2 day double blind placebo controlled trial, followed by analgesia in an open label trial in a subgroup of subjects who chose to use the combination cream for 7 days. Blood analysis revealed no significant systemic absorption of either agent after 7 days of treatment, and creams were well tolerated. A larger scale randomized trial over a longer interval is warranted to examine further effects observed in the open label trial.

Inhalation efficacy of RFI-641 in an African green monkey model of RSV infection

Human respiratory syncytial virus (RSV) is a major cause of acute upper and lower respiratory tract infections. RFI-641 is a novel RSV fusion inhibitor with potent in vitro activity. In vivo efficacy of RFI was determined in an African green monkey model of RSV infection involving prophylactic and therapeutic administration by inhalation exposure. Inhalation was with an RFI-641 nebulizer reservoir concentration of 15 mg/ml for 15 minutes (short exposure) or 2 hours (long exposure). Efficacy and RFI-641 exposure was determined by collection of throat swabs, nasal washes and bronchial alveolar lavage (BAL) on selected days. The short-exposure group (15 minutes) exhibited no effect on the nasal, throat or BAL samples. The throat and nasal samples for the long-exposure group failed to show a consistent reduction in viral titers. RFI-641 2 hours exposure-treated monkeys showed a statistically significantly log reduction for BAL samples of 0.73-1.34 PFU/ml (P-value 0.003) over all the sampling days. Analysis indicates that the long-exposure group titer was lower than the control titer on day 7 and when averaged across days. The results of this study demonstrate the ability of RFI-641 to reduce the viral load of RSV after inhalation exposure in the primate model of respiratory infection.

Cannabis use for chronic non-cancer pain: results of a prospective survey

There has been a surge in interest in medicinal cannabis in Canada. We conducted a questionnaire survey to determine the current prevalence of medicinal cannabis use among patients with chronic non-cancer pain, to estimate the dose size and frequency of cannabis use, and to describe the main symptoms for which relief was being sought. Over a 6-week period in mid-2001, 209 chronic non-cancer pain patients were recruited in an anonymous cross-sectional survey. Seventy-two (35%) subjects reported ever having used cannabis. Thirty-two (15%) subjects reported having used cannabis for pain relief (pain users), and 20 (10%) subjects were currently using cannabis for pain relief. Thirty-eight subjects denied using cannabis for pain relief (recreational users). Compared to never users, pain users were significantly younger (P=0.001) and were more likely to be tobacco users (P=0.0001). The largest group of patients using cannabis had pain caused by trauma and/or surgery (51%), and the site of pain was predominantly neck/upper body and myofascial (68% and 65%, respectively). The median duration of pain was similar in both pain users and recreational users (8 vs. 7 years; P=0.7). There was a wide range of amounts and frequency of cannabis use. Of the 32 subjects who used cannabis for pain, 17 (53%) used four puffs or less at each dosing interval, eight (25%) smoked a whole cannabis cigarette (joint) and four (12%) smoked more than one joint. Seven (22%) of these subjects used cannabis more than once daily, five (16%) used it daily, eight (25%) used it weekly and nine (28%) used it rarely. Pain, sleep and mood were most frequently reported as improving with cannabis use, and 'high' and dry mouth were the most commonly reported side effects. We conclude that cannabis use is prevalent among the chronic non-cancer pain population, for a wide range of symptoms, with considerable variability in the amounts used. Discussions between patients and health care providers concerning cannabis use may facilitate education and follow up, and would allow side effects and potential interactions with other medications to be monitored. Clinical trials of cannabis for chronic non-cancer pain are warranted.

Antidepressants as analgesics: a review of randomized controlled trials

This review provides an overview of 59 randomized placebo-controlled trials that examined the analgesic effect of antidepressants. To summarize, there is significant evidence that the tricyclic group of antidepressants is analgesic and that trazodone is not; the data regarding selective serotonin reuptake inhibitors are conflicting. To date, there are no randomized controlled trials examining the potential analgesic action of nefazodone or venlafaxine, but on the basis of initial clinical reports and its structural similarity to other analgesics, venlafaxine shows promise as an analgesic.