European journal of pain : EJP
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The formalin test is a well-established model for assessing nociceptive processes and analgesic drug effects. Previous studies have provided statistical validation of optimal procedures for conducting and scoring the rat formalin test. In the mouse model, formalin concentration has been subjected to validation studies. ⋯ Multiple regression analyses defined the optimal second-phase formalin response in outbred, Swiss-Webster mice as 15-35 min post formalin injection, and revealed that the second-phase response is best characterized by the cumulative time spent biting/licking the injected paw. Finally, paw physiological measures provided convergent evidence of nociceptive and antinociceptive processes in the mouse formalin test. Copyright 1998European Federation of Chapters of the International Association for the Study of Pain.
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A double-blind, randomized, placebo-controlled trial was conducted to study the analgesic efficacy of the NMDA (N-methyl-D-aspartate) receptor antagonist memantine (1-amino-3,5-dimethyladamantane hydrochloride) in relieving postherpetic neuralgia (PHN). Memantine (or an identical-looking placebon=12/group) was administered at a dose of 10 mg/day for one week, and 20 mg/day for an additional 4 weeks. All patients were required to record their pain level twice daily during the entire study period, with the use of a 0-10 numerical pain scale (NPS). ⋯ Although three patients were withdrawn from the memantine group and only one from the control group, no differences in incidence of adverse effects between the two groups were found. Study results show that memantine is ineffective in reducing spontaneous and evoked pain in patients with PHN. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.
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Positive results of pilot studies of the effect of staphylococcus toxoid vaccine in patients with fibromyalgia and chronic fatigue syndrome were the incitement to the present, placebo-controlled study. It included 28 patients who fulfilled the criteria for both fibromyalgia and chronic fatigue syndrome. The effect of vaccination with a staphylococcus toxoid was compared with the effect of injections of sterile water. ⋯ Fifty percent were rehabilitated successfully and resumed half-time or full-time work. The results of this study support the authors>> hypothesis that treatment with staphylococcus toxoid may be a fruitful strategy in patients with fibromyalgia and chronic fatigue syndrome. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.
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Tramadol is a widely-used analgesic for pre- and post-operative pain which has a different pharmacological profile to that of classical opioids, since it does not induce respiratory depression, constipation, sedation, tolerance or dependence. However, tramadol frequently produces nausea and vomiting as side-effects. In the present study, the interactions between tramadol and several adrenergic and serotonergic compounds with antinociceptive activity were studied by isobolographic analysis. ⋯ The synergies observed with these combinations suggest a complex modulation of the descending noradrenergic and serotonergic systems that exert inhibitory influences on the transmission of nociceptive information, probably in addition to effects on receptors in the primary neurons of the spinal cord. The co-administration of analgesic drugs that produce superadditive effects constitutes a significant new avenue for the treatment of pain, since a similar level of antinociception can be obtained with considerable reductions in the dose of each analgesic. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.