The Clinical journal of pain
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Randomized Controlled Trial Clinical Trial
The relationship between plasma beta-endorphin, opioid receptor activity, and silent myocardial ischemia.
To investigate the role of the opioid system in the pathophysiology of silent ischemia through opiate antagonism with naloxone, and to determine the reproducibility of resting and postexercise beta-endorphin levels in predominantly asymptomatic patients with coronary artery disease. ⋯ (a) naloxone failed to precipitate angina in this population of patients with silent ischemia; (b) naloxone appears to exert an analgesic effect at low doses; and (c) a variability of 5 pM at rest and 13 pM after exercise might be expected in predominantly asymptomatic patients due to random variation, which is comparable with results found in normal subjects.
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Randomized Controlled Trial Clinical Trial
Intrathecal baclofen suppresses central pain in patients with spinal lesions. A pilot study.
To assess the efficacy of acute intrathecal (i.t.) baclofen on chronic, dysesthetic, and spasm-related pain (SRP) among patients with spinal spasticity [i.e., multiple sclerosis (MS), spinal cord injury (SCI), transverse myelitis (TMy)]. ⋯ The suppressive action of i.t. baclofen on spontaneous and evoked (allodynia) dysesthetic pain suggests that a dysfunctional spinal gamma-aminobutyric acidB receptor system, including functional supersensitivity, is associated with the phenomenon of central pain among patients with spinal lesions. Temporal dissociation regarding the action on dysesthetic pain and SRP suggests that disparate central mechanisms subserve the two clinical states.
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Randomized Controlled Trial Clinical Trial
Persistent low-back pain is real. However, diagnostic spinal injections are not helpful in its evaluation.
We endeavored to assess the short-term effects of intrathecal fentanyl and lidocaine in chronic-pain patients by ascertaining whether the opioid fentanyl, by virtue of its lack of sensory and motor paralysis, conferred any diagnostic advantages over lidocaine, a local anesthetic whose effects include sensory and motor paralysis. Neuraxial administration of fentanyl has been touted as an improved diagnostic tool to distinguish between peripheral and central pain, because the absence of sensory and motor effects may avert the patient's presumption of the onset of analgesia based on these cues. Twenty-two patients with persistent low-back pain, whose investigations had determined that they were not surgical candidates, were studied using a counter-balanced, placebo-controlled, and double-blinded crossover design. ⋯ There were no significant differences in the baseline median-pain scores among injection types. The baseline and best cerebrospinal fluid-pain scores were significantly different, suggesting a placebo effect. The best pain scores for fentanyl and lidocaine were superior to their own baseline levels and to the best cerebrospinal fluid scores.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Plasma beta-endorphin is not affected by treatment with imipramine or paroxetine in patients with diabetic neuropathy symptoms.
To determine the possible role of endogenous opioid peptides in the action of imipramine and paroxetine in painful diabetic neuropathy, beta-endorphin concentrations in plasma were measured in 20 patients during a double-blind, placebo-controlled randomized three-way crossover trial. Despite a significant reduction in neuropathy symptoms during both imipramine and paroxetine treatment, the beta-endorphin level was unaltered throughout the study. The plasma concentration of beta-endorphin was not related to plasma drug concentrations. Thus, this study does not provide evidence of a role of endogenous opioid peptides in the mechanism of action of imipramine and paroxetine in painful diabetic neuropathy.
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Comment Letter Randomized Controlled Trial Clinical Trial
The needle and the brain: psychophysiological factors involved in nerve blocking for chronic pain. In response to article by Drs. Brena, Chapman, and Sanders.