Attitudes Towards and Management of Opioid-induced Hyperalgesia: A Survey of Chronic Pain Practitioners.

OBJECTIVES: Opioid-induced hyperalgesia (OIH) is a phenomenon whereby opioids increase patients' pain sensitivity, complicating their use in analgesia. We explored practitioners' attitudes towards, and knowledge concerning diagnosis, risk factors, and treatment of OIH. MATERIALS AND METHODS: We administered an 18-item cross-sectional survey to 850 clinicians that managed chronic pain with opioid therapy. RESULTS: The survey response rate was 37% (318/850). Most respondents (240/318, 76%) reported they had observed patients with OIH in their practice, of which 38% (84/222) reported OIH affected >5% of their chronic pain patients. The majority (133/222, 60%) indicated that OIH could result from any dose of opioid therapy. The most commonly endorsed chronic pain conditions associated with the development of OIH were fibromyalgia (109/216, 51%) and low back pain (91/216, 42%), while 42% (91/216) indicated that no individual chronic pain condition was associated with greater risk of OIH. The most commonly endorsed opioids associated with the development of OIH were oxycodone (94/216, 44%), fentanyl (86/216, 40%), and morphine (84/216, 39%); 27% (59/216) endorsed that no specific opioid was more likely to result in OIH. Respondents commonly managed OIH by opioid dose reduction (147/216, 68%), administering a nonopioid adjuvant (133/216, 62%), or discontinuing opioids (95/216, 44%). DISCUSSION: Most clinicians agreed that OIH is a complication of opioid therapy, but were divided regarding the prevalence of OIH, etiological factors, and optimal management.

What's new in chronic pain pathophysiology.

The understanding of pain pathophysiology is continuously evolving. Identifying underlying cellular and subcellular pathways helps create opportunities for targeted therapies that may prove to be effective interventions. This article is an update on four areas of developing knowledge as it pertains to clinical management of patients with pain: nerve growth factor antagonists, microglial modulation, AMP-activated protein kinase activators, and genetic pain factors. Each of these areas represents novel targets for targeted therapies to prevent, treat, and modify the disease course of acute, chronic, and neuropathic pain. Currently most pain management techniques do not target these pathways directly, but there is promising evidence to suggest that the field is advancing toward available therapies in the near future.

La compréhension de la pathophysiologie de la douleur est en constante évolution. Le fait de déterminer les voies cellulaires et sous-cellulaires sous-jacentes permet d'ouvrir des possibilités de traitements ciblés qui peuvent se montrer efficaces. Cet article fait le point sur quatre domaines du développement des connaissances relatives à la prise en charge clinique des patients souffrant de douleur : les antagonistes du facteur de croissance des nerfs, la modulation de la microglie, les activateurs de la protéine kinase activée par l'AMP et les facteurs génétiques de la douleur. Chacun de ces domaines représente de nouvelles cibles pour des thérapies ciblées visant à prévenir, traiter et modifier l'évolution de la douleur aiguë, chronique et neuropathique. Actuellement, la plupart des techniques de prise en charge de la douleur ne ciblent pas directement ces voies, mais il existe des données probantes prometteuses qui portent à croire que ce domaine progresse vers la disponibilité de traitements dans un avenir rapproché.

Types and epidemiology of cancer-related neuropathic pain: the intersection of cancer pain and neuropathic pain.

Neuropathic pain--pain resulting from a lesion, damage, or dysfunction of the somatosensory nervous system--can arise through several distinct etiologies ranging from toxicity, surgery, radiation, and trauma to congenital disorders. Neuropathic pain is widely recognized as a common consequence of cancer and results from administration of several common oncology drugs. It not only impacts quality of life, but it also impacts patient outcomes because of resulting treatment delays, dose reductions, and discontinuations. We estimate that the cost of the problem in the U.S. alone is approximately $2.3 billion. Despite its widely recognized importance, there is a paucity of reliable information available regarding the incidence, prevalence of patient-and physician-reported severity, and time course of cancer-related neuropathic pain. To address this severe knowledge gap, we need new, high-quality, population-based studies of individual cancer pain syndromes and conditions. However, in order to gather this information, we also need substantial improvements in the specific classification of cancer-related neuropathic syndromes and better validated diagnostic tools that can help to elucidate the incidence, prevalence, severity, and potential economic impact of cancer-associated neuropathies.

Strategies in pain management: new and potential indications for COX-2 specific inhibitors.

The role of the coxibs in the management of osteoarthritis and rheumatoid arthritis has been widely discussed, but there are other potential applications for the coxibs that have received less attention. Here we consider the use of the coxibs in acute pain syndromes such as primary dysmenorrhea and the pain associated with dental extraction, as well as considering their application in chronic low back pain and cancer pain. Another area where the coxibs may prove particularly beneficial is in the management of post-surgical pain. Traditional post-surgical analgesia has involved the use of non-selective NSAIDs and opioids, but these agents can be associated with side effects such as post-operative bleeding, gastrointestinal problems, nausea, and constipation. Because the coxibs do not inhibit COX-1 dependent platelet aggregation like traditional NSAIDs, the risk of post-surgical bleeding is reduced. The careful application of coxibs as part of a multi-modal approach to pain management in the perioperative period can reduce the requirement for opioid medications and thus reduce the risk of post-operative complications such as ileus. In the future, coxibs are likely to play an important role in multi-modal perioperative analgesic regimens with the aim of reducing post-operative periods of convalescence.

Anaesthetic team and the role of nurses--North American perspective.

Anaesthesia is an American invention but the development of anaesthesia practice took two paths at its inception. The American-based ether anaesthetic technique allowed for non-physician personnel to administer the drug. As nurses already played a role in assisting surgeons, it was logical for them to assist in the anaesthetic. This article discusses the historical events leading to the development of nurse anaesthesia practice in the USA. The current status of physician and nurse anaesthetist interactions--both harmonious and acrimonious--are presented.

Emerging options with coxib therapy.

Future clinical applications of cyclooxygenase (COX)-2-selective inhibitors (coxibs) are likely to extend beyond their current use as oral analgesics in high-risk arthritis patients. The clinical utility of coxibs for the treatment of Alzheimer's disease (AD) is under investigation. Epidemiological surveys, preclinical studies, and preliminary clinical trials with nonsteroidal anti-inflammatory drugs (NSAIDs) have suggested that inflammatory mechanisms play a role in the neurodegeneration of AD. Clinical trials are currently being conducted to determine the effect of coxibs on the rate of AD progression. The use of coxibs as chemopreventive agents in colorectal cancer (CRC) is also under investigation. The chemopreventive benefits of coxibs to promote cell death (apoptosis) and inhibit angiogenesis in CRC have been shown in tumor cell lines and in animal and human models. In addition, palliative care clinicians and oncologists are increasingly including coxibs in their management of cancer pain. Coxibs are utilized for their opioid-sparing effect in the management of cancer pain, without impairing wound healing, or promoting bleeding diathesis (antiplatelet effects) or adverse gastrointestinal effects in patients receiving chemotherapy or radiation treatment.

Neurolytic superior hypogastric plexus block for chronic pelvic pain associated with cancer.

Twenty-six patients with extensive gynecologic, colorectal or genitourinary cancer who suffered uncontrolled, incapacitating pelvic pain were enrolled in this study during a 1-year period. All the patients receiving oral opioids who developed poor pain response due to the progression of disease or untoward side effects necessitating other modes of therapy were eligible to participate. Bilateral percutaneous neurolytic superior hypogastric plexus blocks with 10% phenol were performed in every patient, 1 day after receiving successful diagnostic blocks using 0.25% bupivacaine (BUP). All patients reported a visual analog pain score (VAPS) of 10 of 10 before the block. Eighteen patients (69%) had satisfactory pain relief (VAPS < 4 of 10): 15 (57%) after 1 block and 3 (12%) after a second block. The remaining 8 patients (31%) had moderate pain control (VAPS 4-7 of 10) after 2 blocks and received epidural bupivacaine-morphine (BUP-MS) therapy with good results. Both groups experienced significant reductions in oral opioid therapy after the neurolytic blocks. No additional blocks were required by patients who had a good response during a follow-up period of 6 months. No complications related to the block were experienced by any patient. In conclusion, neurolytic superior hypogastric plexus block was both effective in relieving pain in 69% of the patients studied (95% confidence interval of 48-85%). Additional neurolytic blocks using higher volumes of the neurolytic agent may be needed in patients with extensive retroperitoneal disease, a group in whom moderate or poor results should be expected.