Pain
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Randomized Controlled Trial Clinical Trial
Tramadol relieves pain and allodynia in polyneuropathy: a randomised, double-blind, controlled trial.
It is generally believed that opioids relieve neuropathic pain less effectively than nociceptive pain and that they have no effect on some of the key characteristics of neuropathic pain such as touch-evoked pain (allodynia). Tramadol is an analgesic drug acting directly on opioid receptors and indirectly on monoaminergic receptor systems. The aim of this trial was to determine whether tramadol relieved painful polyneuropathy and reduced allodynia. ⋯ Their ratings for pain (median 4 vs. 6, P=0.001), paraesthesia (4 vs. 6, P=0.001) and touch-evoked pain (3 vs. 5, P<0.001) were lower on tramadol than on placebo, as were their ratings of allodynia (0 vs. 4, P=0.012). The number needed to treat to obtain one patient with >/=50% pain relief was 4.3 (95% confidence interval 2.4-20). It is concluded that tramadol appears to relieve both ongoing pain symptoms and the key neuropathic pain feature allodynia in polyneuropathy.
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Randomized Controlled Trial Clinical Trial
200 mg daily of lamotrigine has no analgesic effect in neuropathic pain: a randomised, double-blind, placebo controlled trial.
Anticonvulsant drugs are commonly used in neuropathic pain. There is anecdotal evidence of an analgesic effect of the anticonvulsant lamotrigine in neuropathic pain, but this is verified by few randomised controlled trials. This randomised, double-blind, placebo controlled trial of examined the effect of lamotrigine in a dose increasing to 200 mg in 100 patients with neuropathic pain. ⋯ There were no correlation between any other measured variable. There was no significant change in any variable measured over the eight week period when lamotrigine was used. It is concluded that at the dose used and using the dose escalation regime described, lamotrigine had no effect on either pain, component pain symptoms or quality of life variables.
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Comparative Study
A comparison of faces scales for the measurement of pediatric pain: children's and parents' ratings.
Faces scales have become the most popular approach to eliciting children's self-reports of pain, although different formats are available. The present study examined: (a) the potential for bias in children's self-reported ratings of clinical pain when using scales with smiling rather than neutral 'no pain' faces; (b) levels of agreement between child and parent reports of pain using different faces scales; and (c) preferences for scales by children and parents. Participants were 75 children between the ages of 5 and 12 years undergoing venepuncture, and their parents. ⋯ The level of agreement between child and parent reports of pain was low and did not vary as a function of the scale type used; parents overestimated their children's pain using all five scales. Children and parents preferred scales that they perceived to be happy and cartoon-like. The results of this study indicate that subtle variations in the format of faces scales do influence children's and parents' ratings of pain in clinical settings.
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Post mastectomy pain syndrome is a condition which can occur following breast surgery and has until recently been regarded as uncommon. Recent reports have suggested that it may affect 20% or more of women following mastectomy. The symptoms are distressing and may be difficult to treat however treatment for neuropathic pain can be successful. ⋯ Relationship between the frequency of post mastectomy pain syndrome and radiotherapy, chemotherapy and the use of tamoxifen are difficult to unravel because of the combinations of pre and post operative treatments received confounded by age. The implications of a much higher frequency of post mastectomy pain are discussed with regard to management and counselling. The high frequency of the syndrome in the younger women is important and possible explanations are explored.
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To elucidate the underlying mechanisms of pathological pain, it is important and necessary to develop an animal model characterized by both spontaneous tonic pain and hyperalgesia with a prolonged duration post-tissue injury. In this report, we investigated whether the two animal models of spontaneous tonic pain (the formalin test and the bee venom test) could develop a hyperalgesia to mechanical and thermal stimuli in the injured area following subcutaneous (s.c. ) administration of the two chemical agents into the plantar surface of one hindpaw in the conscious rats. It was found that the persistent nociceptive response (flinching and lifting/licking the injected hindpaw) was monophasic and lasted for 1-2 h followed by a 72-96 h period of reduction in mechanical threshold and heat latency of withdrawal reflex in the bee venom injection area; however, in contrast, the spontaneous pain-related response was biphasic followed by a permanent hypoalgesia or analgesia in the formalin injection area although the duration and response intensity of spontaneous pain was comparable with those following bee venom treatment. ⋯ On the other hand, s.c. bee venom injection produced a striking edema and redness of the plantar surface for nearly the same period as the development of hyperalgesia, while the edema and redness could not be obviously observed after the formalin treatment. In the control study, repetitive suprathreshold mechanical or heat stimuli applied to the plantar surface with or without saline treatment did not significantly influence the mechanical threshold or heat latency, suggesting that the phenomena of mechanical and heat hyperalgesia were not the effects of vehicle treatment or those of the stimulus modalities themselves. Taken together, our present results showed that in contrast to s.c. formalin injection, subcutaneous. bee venom injection produced little tissue damage but a striking inflammation accompanied by a prolonged spontaneous pain and a pronounced primary hyperalgesia to mechanical and heat stimuli in the treated hindpaw and a heat, but not mechanical, hyperalgesia in the contralateral hindpaw, implicating that bee venom model may have more advantages over the formalin test and probably other chemoirritants to study the neural mechanisms underlying pathological pain and, especially, the relationship between spontaneous pain and development of hyperalgesia.