Pain
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Comparative Study
Block of NMDA and non-NMDA receptor activation results in reduced background and evoked activity of central amygdala neurons in a model of arthritic pain.
The latero-capsular division of the central nucleus of the amygdala (CeA) is now defined as the 'nociceptive amygdala' because of its high content of neurons activated exclusively or preferentially by noxious stimuli. Multireceptive (MR) neurons that respond to innocuous and, more strongly, to noxious stimuli become sensitized in arthritis pain. This form of nociceptive plasticity involves presynaptic group I metabotropic glutamate receptors, which increase glutamate release. ⋯ All neurons examined received excitatory input from the knee(s) and were MR neurons. A selective NMDA receptor antagonist (AP5) inhibited responses to noxious stimuli more potently in the arthritic pain state (n = 6) than under control conditions before arthritis (n = 8) AP5 also inhibited the enhanced background activity and increased responses to normally innocuous stimuli in arthritis, but had no significant effects on these parameters under control conditions. A selective non-NMDA receptor antagonist (NBQX) inhibited background activity and evoked responses under normal control conditions (n = 6) and in arthritis (n = 8) These data suggest that activation of both NMDA and non-NMDA receptors contributes to pain-related sensitization of amygdala neurons.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Relative analgesic potency of fentanyl and sufentanil during intermediate-term infusions in patients after long-term opioid treatment for chronic pain.
Sufentanil, a potent mu-opioid agonist, historically has not been been given systemically to treat chronic pain. An implantable, fixed-rate osmotic pump that delivers sufentanil subcutaneously is being developed for this purpose. In that transdermal fentanyl may be a useful intermediary to estimate the appropriate sufentanil dose before implant, accurate information is needed about the relative analgesic potency of sufentanil and fentanyl during continuous infusion. ⋯ For the remaining 41 patients, target concentrations associated with adequate analgesia were achieved for both sufentanil and fentanyl. The median value for the equianalgesic concentration ratio (steady-state fentanyl infusion to steady-state sufentanil infusion) was 7.5; mean potency ratio was 7.44 (95% confidence interval 6.8-8.2). During titrated, intermediate-term infusions in patients previously treated with opioids for chronic pain, sufentanil is approximately 7.5 times as potent as fentanyl.
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Comparative Study Clinical Trial Controlled Clinical Trial
The effects of early or late neurolytic sympathetic plexus block on the management of abdominal or pelvic cancer pain.
Neurolytic sympathetic plexus block (NSPB) has been proposed to prevent the development of pain and improve the quality of life of patients with cancer, thus questioning the WHO protocol that proposes the use of invasive methods only as a final resort. This study evaluates the pain relief, opioid consumption and quality of life provided by the use of NSPB in two different phases of cancer pain and compares them with that provided by pharmacological therapy only. Sixty patients with abdominal or pelvic cancer pain were divided into three groups and observed for 8 weeks. ⋯ Opioid-related adverse effects were significantly greater in group III (P < 0.05). The occasional neurolysis-related complications were transitory. The results suggest NSPB for the management of cancer pain should be considered earlier in the disease.
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Comparative Study
Differentiating sensory and affective-sensory pain descriptions in patients undergoing magnetic resonance imaging for persistent low back pain.
The study design is a cross-sectional survey with psychometric analysis. The objective is to determine the validity of a modified version of the Short-Form McGill Pain Questionnaire (SF-MPQ). The SF-MPQ has been widely used to differentiate between reports of sensory and affective pain. ⋯ Correlations with measures of pain intensity and the RM were significant, but slightly lower, for the subscales of the modified 2-factor solution (0.26-0.40) than for the subscales of the previously described 2-factor solutions (0.34-0.45). The MSF-MPQ can be used as a brief tool to differentiate the language used to describe pain in patients who are undergoing lumbar MRI. The evidence indicates that this clinical tool can be used to categorize how these patients describe their pain and potentially may be very valuable in determining the optimal course of treatment.
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Randomized Controlled Trial Comparative Study Clinical Trial
A randomized clinical trial of the effectiveness of a scheduled oral analgesic dosing regimen for the management of postoperative pain in children following tonsillectomy.
The purpose of this study was to determine whether around-the-clock (i.e. ATC) dosing of acetaminophen with codeine, with or without nurse coaching, compared to standard care with as needed (i.e. PRN) dosing: reduced children's reports of pain intensity with and without swallowing; increased pain relief, and increased analgesic consumption. ⋯ No significant differences were found in the amount of nausea and vomiting among the three groups. Scheduled dosing of acetaminophen with codeine did not provide adequate pain relief for children following tonsillectomy. Nurse coaching does not increase parent's adherence with an ATC dosing schedule.