Pain
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Clinical Trial
The influence of psychological variables on postoperative anxiety and physical complaints in patients undergoing lumbar surgery.
Previous research has indicated that postoperative distress is influenced by diverse biographic, medical and psychological variables, such as personality, coping behaviours and anxiety. The influence of state variables, apart from anxiety and coping behaviour, has received scant attention. Furthermore, the influence of coping behaviour has remained unclear. ⋯ Preoperative anxiety and fatigue independently predicted more postoperative physical complaints. No associations were found between the coping behaviours and the postoperative variables. The implications of these results are discussed in relation to intervention strategies aimed at diminishing the stress of surgery.
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The effects of mexiletine, desipramine and fluoxetine in rat models involving central sensitization.
Drugs that are clinically effective (mexiletine and desipramine) or ineffective (fluoxetine) in the treatment of human neuropathic pain were evaluated for efficacy in rat models involving central sensitization (i.e., formalin model and the L5/L6 spinal nerve ligation model of neuropathic pain) using tests that differ in stimulus modality: noxious chemical stimulus (formalin model) as well as noxious (pin prick) and innocuous mechanical stimuli (application of von Frey filaments). Mexiletine (10-100 mg/kg, s.c.) significantly (P < 0.05) attenuated hyperalgesia in formalin-treated (60 mg/kg and 100 mg/kg) and neuropathic rats (100 mg/kg) as well as tactile allodynia in neuropathic rats (100 mg/kg). Desipramine (1-100 mg/kg, s.c.), on the other hand, reduced hyperalgesia significantly (P < 0.05) in formalin-treated (3, 10, 30 and 100 mg/kg) and neuropathic rats (10 mg/kg and 100 mg/kg), but did not reduce tactile allodynia in the neuropathic rats. ⋯ Thus, drugs which are effective in reducing human neuropathic pain consistently attenuated hyperalgesia in formalin-treated or neuropathic rats. Desipramine also distinguished mechanical hyperalgesia from tactile allodynia in rats rendered neuropathic by spinal nerve ligation. These data are consistent with the hypothesis that the neuronal mechanisms underlying these two manifestations of neuropathic pain are different.
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An animal model showing mechanical allodynia following systemic bolus injection of a human/mouse chimeric monoclonal antibody to the GD2 ganglioside (ch14.18) has been established (e.g. pain behavior generated by a light tactile stimulus). This is of clinical relevance since ch14.18 is a promising experimental treatment for pediatric neuroblastoma. The present study examined the hypothesis that allodynic effects of the anti-GD2 antibody are mediated by actions on cutaneous nerve fibers. ⋯ Mean mechanical threshold for A delta fibers in all three antibody treated groups was significantly reduced compared to the saline control; this was not observed for C-fibers in any group. Intravenous bolus injection (15 mg/kg) and infusion of lidocaine (plasma level 0.3-2.2 micrograms/ml) both reduced anti-GD2 associated BA. These data demonstrate that mechanical-allodynia could be produced by action(s) of the anti-GD2 antibody (direct or indirect) on peripheral nerves and suggest intravenous lidocaine as part of the analgesic regimen accompanying anti-GD2 antibody treatment.
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A previously established relationship for deriving dichotomous from continuous information in randomised controlled trials (RCTs) of analgesics has been tested using an independent data set. Individual patient information from 18 RCTs of parallel-group design in acute postoperative pain (after abdominal, gynaecological and oral surgery) was used to calculate the percentage of the maximum possible pain relief score (%maxTOTPAR) and the proportion of patients with > 50%maxTOTPAR for the different treatments. The relationship between the measures was investigated in 85 treatments with over 3400 patients. ⋯ Reports of RCTs of analgesics frequently describe results of studies in the form of mean derived indices, rather than using discontinuous events, such as number or proportion of patients with 50% pain relief. Because mean data inadequately describe information with a non-normal distribution, combining mean data in systematic reviews may compromise the results. Showing that dichotomous data can reliably be derived from mean data in acute pain studies enables data published as means to be used for quantitative systematic reviews which require data in dichotomous form.
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This open prospective study evaluated the combination of initial dose titration with patient-controlled analgesia (PCA) and long-term treatment with transdermal fentanyl in 50 cancer patients requiring opioids for severe pain. The delivery rate of the first transdermal therapeutic system (TTS) was calculated from the self-administered intravenous fentanyl dose during the first 24 h. TTS were changed every 48-72 h, and a different patch size was chosen if necessary. ⋯ Other severe side-effects were not observed. Patient compliance and acceptance were excellent. The results suggest that intravenous PCA is useful for initial dose finding, and transdermal fentanyl is effective and safe during long-term treatment of cancer pain.