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Query: UMLS:C0423716 (Neuropathic pain)
 1,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cancer pain generally responds in a predictable way to analgesic drugs and drug therapy is the mainstay of treatment. A small proportion of patients, of the order of 20%, have pain that does not respond well to conventional analgesic management. Because opioid analgesics are the most important part of this pharmacological approach, a terminology has developed which centres around whether or not pain will respond to opioid analgesics. The terms opioid-responsive-pain and opioid-non-responsive pain, or opioid-resistant-pain, have been used to differentiate between patients whose pain falls into these two broad groups. This terminology is not satisfactory because it implies an all or none phenomenon, that is that pain either does or does not respond to opioid analgesics. Rarely is there such a clear distinction in practice. This is because the end point when titrating dose against pain with strong opioid analgesics is not simply pain relief or lack of relief: adverse effects may limit dose titration. It is preferable to describe patients with pain which is relatively less sensitive to opioids and/or patients where there is an inbalance between analgesia and unwanted effects as having "opioid-poorly-responsive pain". A pragmatic definition of opioid-poorly-responsive pain is pain that is inadequately relieved by opioid analgesics given in a dose that causes intolerable side effects despite routine measures to control them. Included in this definition is so called paradoxical pain which is not a distinct entity. Neuropathic pain is the most common form of opioid-poorly-responsive pain. The underlying pathophysiology remains unclear but abnormal metabolism of morphine is not the cause of a poor response to this drug. Patients with opioid-poorly-responsive-pain should be considered for treatment with the same opioid by an alternative (spinal) route or with an alternative opioid agonist administered by the same route (whether oral or parenteral), in conjunction with adjuvant analgesics such as tricyclic antidepressants. The most commonly used alternative oral opioids are phenazocine and methadone; transdermal fentanyl is an additional option.
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PMID:Opioid responsiveness. 906 Oct 99

Neuropathic pain syndromes are one of the major problems of cancer pain treatment. The present study surveys 593 cancer patients treated by a pain service following the WHO guidelines for relief of cancer pain. Of these, 380 presented with nociceptive, 32 with neuropathic and 181 with mixed (nociceptive and neuropathic) pain. In patients with nociceptive, mixed and neuropathic pain, the average duration of evaluated pain treatment was 51, 53 and 38 days, respectively. Non-opioid or opioid analgesics were given to 99%, 96% and 79%, antidepressants to 8%, 25% and 19%, anticonvulsants to 2%, 22% and 38% and corticosteroids to 26%, 35% and 22% of patients, respectively. Systemic analgesia was supported by palliative antineoplastic treatment (48%, 56% and 38% of patients), nerve blocks (3%, 6% and 6%), psychotherapy (3%, 7% and 3%), physiotherapy (6%, 12% and 13%) and transcutaneous electric nerve stimulation (1%, 6% and 6%). Analgesic treatment resulted in a significant pain relief in all groups of patients, as the mean pain intensity (NRS) decreased from 66 (nociceptive), 65 (mixed) and 70 (neuropathic) on admission to 26, 30 and 28 after 3 days and 18, 17 and 21 at the end of survey. The total outcome of pain treatment was not predicted by the designation to nociceptive, mixed or neuropathic pain. In conclusion, neuropathic cancer pain is not intractable and can be relieved in the majority of patients by treatment following the WHO guidelines.
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PMID:Assessment and treatment of neuropathic cancer pain following WHO guidelines. 992 71

The purpose of this study was to investigate strain-related differences in the onset and maintenance of thermal hyperalgesia following the induction of peripheral nerve injury in two inbred strains of rats (Fischer 344 and Lewis) and two outbred strains of rats (Sprague-Dawley and Wistar). Neuropathic pain was induced via unilateral ligation of the left sciatic nerve with chromic gut sutures. A plantar analgesia meter was used to measure paw-withdrawal latency from the ligated vs. unligated hind paws of inbred vs. outbred strains of rats to investigate strain-related differences in nerve injury-induced thermal hyperalgesia. The results demonstrated no significant effects of animal strain on presurgical paw-withdrawal latency values. Following the sciatic nerve ligation (SNL) surgery, a significant hyperalgesic response was elicited from the Sprague-Dawley and Wistar rats (outbred strains) for at least 28 days. Conversely, data analyses from the inbred strains failed to demonstrate significant hyperalgesic responses to peripheral nerve injury, with the exception of postsurgical day 10. These data emphasize the importance of considering the strain of the rat being investigated before extrapolating the results from animals experiments to treatment strategies for humans with chronic neuropathic pain.
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PMID:Strain differences in neuropathic hyperalgesia. 1063 47

The aim of this study was to evaluate the influence of age and gender on pain characteristics and opioid response in advanced cancer patients followed at home. A perspective study was carried out in a sample of 181 consecutive advanced cancer patients who required opioids in the last 4 weeks before death. Pain intensity and symptoms associated with opioid therapy at weekly intervals for 4 weeks were recorded, as were the previous oncological treatments. Opioid doses increased over time, but remained stable in the last 2 weeks of life, while pain intensity decreased over time despite unchanged use of NSAIDs. A considerable increase in symptom intensity was observed in the last weeks of life, except for nausea and vomiting. Visceral pain was more often reported in women. Male patients more often presented somatic pain mechanisms. Neuropathic pain was associated with higher mean VAS intensity and was equally reported in male and female patients and in the different age groups. Very old patients, who received less chemotherapy, required less opioid doses and reported a lower intensity of some symptoms, while reporting similar pain relief. Dry mouth was more frequent in adults than in very old patients. The identification of specific factors and pain characteristics may be useful in suggesting the likelihood of response in terms of analgesia and opioid-related adverse effects. Age and gender analysis should be included in all cancer pain and symptom control studies, as they may have an influence on cancer pain prognosis.
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PMID:Factors influencing the opioid response in advanced cancer patients with pain followed at home: the effects of age and gender. 1073 59

Neuropeptide Y (NPY) is believed to exert antinociceptive actions by inhibiting the release of substance P and other 'pain neurotransmitters' in the spinal cord dorsal horn. However, the physiological significance and potential therapeutic value of NPY remain obscure. It is also unclear which receptor subtype(s) are involved. To identify a possible physiological role for the NPY Y1 receptor in pain transmission, we generated NPY Y1 receptor null mutant (Y1-/-) mice by homologous recombination techniques. Here we show that Y1-/- mice develop hyperalgesia to acute thermal, cutaneous and visceral chemical pain, and exhibit mechanical hypersensitivity. Neuropathic pain is increased, and the mice show a complete absence of the pharmacological analgesic effects of NPY. In the periphery, Y1 receptor activation is sufficient and required for substance P release and the subsequent development of neurogenic inflammation and plasma leakage. We conclude that the Y1 receptor is required for central physiological and pharmacological NPY-induced analgesia and that its activation is both sufficient and required for the release of substance P and initiation of neurogenic inflammation.
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PMID:Reduced antinociception and plasma extravasation in mice lacking a neuropeptide Y receptor. 1120 47

Neuropathic pain is a challenge for clinicians because it is resistant to commonly prescribed analgesics, such as opioids and nonsteroidal antiinflammatory drugs. Fortunately, adjuvant analgesics, drugs not typically thought of as pain relievers, may be effective. It is helpful to classify adjuvant analgesics used to treat neuropathic pain into two broad categories: (1) membrane stabilizing agents, which inhibit ectopic discharges on damaged neural membranes, and (2) drugs that enhance dorsal horn inhibition, which may augment biogenic amine or GABAergic mechanisms in the dorsal horn of the spinal cord. Current evidence regarding efficacy generally does not support the use of one drug over another, and selection of a particular drug may depend on experience or expected side effects. The overall efficacy of tricyclic antidepressants for neuropathic pain is modest, and they may produce intolerable side effects. Based on current studies, gabapentin is a reasonable alternative to antidepressants, as initial monotherapy or add-on treatment, particularly for painful diabetic peripheral neuropathy and postherpetic neuralgia. From a practical standpoint, to optimize analgesia more than one drug may be necessary. Although polypharmacy is the result, this approach may improve therapy and minimize side effects. From a safety standpoint, medications generally should be started at low doses and titrated to effect. Although labor-intensive, this strategy can improve compliance and optimize patient care.
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PMID:Neuropathic pain: Review of mechanisms and pharmacologic management. 1145 64

Contemporary medicine is characterized by sophisticated specialization of the individual physician. The specialist in urological surgery may undertake one of the most important and primary medical tasks, the mitigation and therapy of pain. This review aims to provide an overview of the concepts of pain therapy in urology. Most patients benefit from basic concepts of analgesia, including measuring and documenting pain scores at the bedside by the nursing staff. Patients undergoing very painful operative procedures require more potent techniques of analgesia, e.g. intravenous patient-controlled analgesia and epidural analgesia. These techniques need adequate supervision by an acute pain service, but their implementation improves the outcome in some situations. Pain in acute renal obstruction varies in intensity and duration; hence, analgesic therapy has to be tailored to the individual patient. Pain syndromes from cancer can be more complex than those after surgery. Neuropathic pain is probably the most difficult to manage and requires consultation with a pain-management specialist. In the case of neuropathic pain, treatment only with opioids is of limited efficacy and combination with co-analgesics is necessary. In addition, invasive analgesic therapies should sometimes be considered.
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PMID:The treatment of pain in urology. 1217 84

Antidepressant drugs have been widely used for many years to treat neuropathic pain, despite the rationale for their use was still unclear. We review recent insights into their mechanism of action, focusing on central and peripheral analgesic actions. Beside the traditional monoaminergic hypothesis, other pharmacological actions have been studied: antidepressants interfere with the opioid system, interact with the NMDA receptors, and inhibit ion channel activity. Firm evidence from randomised controlled trials demonstrated that TCAs are the most effective drugs for treatment of different neuropathic pain conditions. They exhibit the lowest number needed to treat compare with all other drugs investigated. SSRIs failed to provide an adequate analgesia, due to their high selectivity. SSRIs are clearly less effective than TCAs (NNT: 6.7 vs 2.4) supporting the hypothesis that a balanced inhibition of noradrenaline and serotonin reuptake is more effective in relieving pain. On the basis of initial results Venlafaxine seems to be the most promising of the newer antidepressants as analgesic. Newer antidepressants show a better side effects profile, but further investigation are warranted to clarify their potential role in management of pain. Neuropathic pain remains a challenging condition to treat, as all currently available drugs fail to achieve adequate pain relief in a significant proportion of patients. TCAs should be currently considered the first choice in treatment of neuropathic pain and the gold standard against which to compare other potential new treatments.
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PMID:Mechanism-based treatment in chronic neuropathic pain: the role of antidepressants. 1617 54

Neuropathic pain is a major clinical problem unresolved by available therapeutics. Spinal cord glia play a pivotal role in neuropathic pain, via the release of proinflammatory cytokines. Anti-inflammatory cytokines, like interleukin-10 (IL-10), suppress proinflammatory cytokines. Thus, IL-10 may provide a means for controlling glial amplification of pain. We recently documented that intrathecal IL-10 protein resolves neuropathic pain, albeit briefly (approximately 2-3 h), given its short half-life. Intrathecal gene therapy using viruses encoding IL-10 can also resolve neuropathic pain, but for only approximately 2 weeks. Here, we report a novel approach that dramatically increases the efficacy of intrathecal IL-10 gene therapy. Repeated intrathecal delivery of plasmid DNA vectors encoding IL-10 (pDNA-IL-10) abolished neuropathic pain for greater than 40 days. Naked pDNA-IL-10 reversed chronic constriction injury (CCI)-induced allodynia both shortly after nerve injury as well as 2 months later. This supports that spinal proinflammatory cytokines are important in both the initiation and maintenance of neuropathic pain. Importantly, pDNA-IL-10 gene therapy reversed mechanical allodynia induced by CCI, returning rats to normal pain responsiveness, without additional analgesia. Together, these data suggest that intrathecal IL-10 gene therapy may provide a novel approach for prolonged clinical pain control.
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PMID:Repeated intrathecal injections of plasmid DNA encoding interleukin-10 produce prolonged reversal of neuropathic pain. 1694 47

Neuropathic pain is defined as pain caused by a lesion in the nervous system and is common in clinical practice. Diagnosis can be difficult. Recommendations for first-line pharmacologic treatments are based on positive results from multiple, randomized, controlled trials, and recommendations for second-line pharmacologic treatments are based on the positive result of a single, randomized, controlled trial or inconsistent results of multiple, randomized, controlled trials. The results of published trials and clinical experience provide the foundation for specific recommendations for first-line treatments, which include gabapentin, 5% lidocaine patch, opioid analgesics, tramadol hydrochloride, and tricyclic antidepressants (TCAs). Gabapentin (up to 3,600 mg/day) significantly reduced pain compared with placebo; improvements in sleep, mood, and quality of life were also demonstrated. Adverse effects of gabapentin include somnolence and dizziness, and, less commonly, gastrointestinal symptoms and mild peripheral edema. Thus, monitoring and dosage adjustment are required, without discontinuation of the drug. Gabapentin combined with morphine achieved better analgesia at lower doses of each drug than each drug alone, with only mild adverse effects. The first medication that proved effective for neuropathic pain in placebo-controlled trials was TCAs. Treatment decisions for patients with neuropathic pain can be difficult. Interest in the mechanisms and treatment of chronic neuropathic pain has increased during the past years, resulting in significant treatment advances in the future. In this article all recent knowledge on therapeutic management of chronic neuropathic pain is presented.
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PMID:Therapeutic management of chronic neuropathic pain: an examination of pharmacologic treatment. 1719 64


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