Pain
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Randomized Controlled Trial Comparative Study
Different profiles of buprenorphine-induced analgesia and antihyperalgesia in a human pain model.
Different mechanisms were proposed for opioid-induced analgesia and antihyperalgesia, which might result in different pharmacodynamics. To address this issue, the time course of analgesic and antihyperalgesic effects of intravenous (i.v.) and sublingual (s.l.) buprenorphine was assessed in an experimental human pain model. Fifteen volunteers were enrolled in this randomized, double-blind, and placebo controlled cross-over study. ⋯ The half-life of buprenorphine-induced analgesic and antihyperalgesic effects were 171 and 288 min, respectively. In contrast to pure mu-receptor agonists, buprenorphine exerts a lasting antihyperalgesic effect in our model. It will be of major clinical interest whether this difference will translate into improved treatment of pain states dominated by central sensitization.
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Randomized Controlled Trial Comparative Study
Iontophoretic administration of S(+)-ketamine in patients with intractable central pain: a placebo-controlled trial.
The efficacy of 50 and 75 mg S(+)-ketamine administered daily by an iontophoresis-assisted transdermal drug delivery system was tested against placebo in a randomized, double-blind design in 33 patients with central neuropathic pain. At baseline and 1 week after the start of treatment subjects were evaluated with standard measures of efficacy: pain intensity measured by visual analog scale (VAS), health status (Pain Disability Index and EQ-5D) and quality of life (SF-36). Safety assessment included incidence and intensity of adverse events. ⋯ Iontophoretic administration of S(+)-ketamine was well tolerated with a low incidence of adverse events (mild and transient in nature, resolving spontaneously). Iontophoretic administration of S(+)-ketamine was not more effective than placebo treatment in reducing pain scores in patients with severe central neuropathic pain. However, iontophoretic administration of 75 mg S(+)-ketamine improved the health status and the quality of life in these patients.
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Comparative Study
Motor cortex stimulation for refractory neuropathic pain: four year outcome and predictors of efficacy.
Thirty-one patients with medically refractory neuropathic pain were included in a prospective evaluation of motor cortex stimulation. The long-term outcome was evaluated using five variables: (a) rate (percentage) of pain relief, (b) pain scores as assessed on VAS, (c) postoperative decrease in VAS scores, (d) reduction in analgesic drug intake, (e) a dichotomic (yes/no) response to the question whether the patient would accept, under similar circumstances, to be operated on again. Pain relief was rated as excellent (>70 % pain relief) in 10 % of cases, good (40-69 %) in 42 %, poor (10-39 %) in 35 % and negligible (0-9 %) in 13 %. ⋯ Neither preoperative motor status, pain characteristics, type or localisation of lesions, quantitative sensory testing, Somatosensory Evoked Potentials, nor the interval between pain and surgery were found to predict the efficacy of MCS. The level of pain relief, as evaluated in the first month following implantation was a strong predictor of long-term relief (regression analysis, R=0.744; p<0.0001). These results confirm that MCS can be a satisfactory and durable alternative to medical treatments in patients with refractory pain, and suggest that the efficacy of MCS may be predicted in the first month of therapy.
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Chronic pain causes significant problems in the lives of many adolescents, considerably affecting their physical, psychological and social functioning. The assessment of the multidimensional impact of chronic pain is an essential clinical task. This study reports on the development and psychometric evaluation of the Bath Adolescent Pain Questionnaire (BAPQ); an assessment tool designed specifically for use with adolescents who experience chronic pain. ⋯ The BAPQ may offer a comprehensive way to assess the widespread deleterious impact of adolescent chronic pain in both a research and clinical setting. Further investigation is needed on the predictive validity of the subscales. Additional data from samples of patients with diagnoses that are not musculoskeletal in origin would be of great assistance.
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Comparative Study
Heart rate mediation of sex differences in pain tolerance in children.
Despite evidence supporting the existence of important sex-related differences in pain, the mechanisms underpinning such differences are not well understood. The aim of this study is to examine the relationship between sex and pubertal differences in autonomic arousal and pain tolerance to laboratory pain stimuli in healthy children. We tested the following specific hypotheses: (1) females would have greater autonomic arousal and less pain tolerance than males, and (2) this sex difference in pain tolerance would be mediated by autonomic arousal. ⋯ There were also significant effects for puberty, but these did not vary by sex. Overall, early pubertal children had greater pre-trial HR and less pain tolerance than those in late puberty for both cutaneous pressure and thermal pain across sex. These results suggest that autonomic arousal may be a mediator of sex-related differences in pain responses in children.