Pain
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Randomized Controlled Trial Multicenter Study
A randomized, double-blind, placebo-controlled trial evaluating the efficacy and safety of ABT-594 in patients with diabetic peripheral neuropathic pain.
ABT-594 is a neuronal nicotinic acetylcholine receptor (NNR) agonist that exhibits potent analgesic activity in preclinical models of acute, chronic, and neuropathic pain. The purpose of this phase 2, randomized, multicenter, double-blind, placebo-controlled study was to evaluate the safety and analgesic efficacy of ABT-594 in patients with diabetic peripheral neuropathic pain (DPNP). A total of 266 DPNP patients were randomized 1:1:1:1 to receive placebo, ABT-594 150 microg BID, ABT-594 225 microg BID, or ABT-594 300 microg BID. ⋯ However, adverse event (AE) dropout rates were significantly higher in all three ABT-594 treatment groups (28% for 150 microg BID, 46% for 225 microg BID, and 66% for 300 microg BID) than for the placebo group (9%). Consistent with the expected side-effect profile of NNR agonists, the most frequently reported AEs were nausea, dizziness, vomiting, abnormal dreams, and asthenia. This study establishes proof of concept for NNR agonists as a new class of compounds for treating neuropathic pain.
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Randomized Controlled Trial
Duloxetine, a centrally acting analgesic, in the treatment of patients with osteoarthritis knee pain: a 13-week, randomized, placebo-controlled trial.
Pain is a common cause of disability in osteoarthritis. Duloxetine, a serotonin and norepinephrine reuptake inhibitor (SNRI), has demonstrated analgesic effects in diabetic peripheral neuropathy and fibromyalgia. Considering its central mechanism of action, duloxetine may be effective in other pain states with evidence of central sensitization. ⋯ Duloxetine was superior to placebo on the primary efficacy measure (weekly mean 24-h pain scores) beginning at Week 1 and continuing through the treatment period (P < or = .05). There was also a significant improvement in the WOMAC physical functioning subscale and several other secondary outcomes. Adverse-event rates did not differ significantly between treatment groups (49.5% for duloxetine 60-120 mg/day, and 40.8% for placebo).
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Randomized Controlled Trial
Endogenous opioids may buffer effects of anger arousal on sensitivity to subsequent pain.
Evidence suggests that anger and pain are related, yet it is not clear by what mechanisms anger may influence pain. We have proposed that effects of anger states and traits on pain sensitivity are partly opioid mediated. In this study, we test the extent to which analgesic effects of acute anger arousal on subsequent pain sensitivity are opioid mediated by subjecting healthy participants to anger-induction and pain either under opioid blockade (oral naltrexone) or placebo. ⋯ Results of ANOVAs show significant Drug Condition x Task Order interactions for sensory pain ratings (MPQ-Sensory) and angry and nervous affect during pain-induction, such that participants who underwent anger-induction prior to pain while under opioid blockade (naltrexone) reported more pain, and anger and nervousness than those who underwent the tasks in the same order, but did so on placebo. Results suggest that for people with intact opioid systems, acute anger arousal may trigger endogenous opioid release that reduces subsequent responsiveness to pain. Conversely, impaired endogenous opioid function, such as that found among some chronic pain patients, may leave certain people without optimal buffering from the otherwise hyperalgesic affects of anger arousal, and so may lead to greater pain and suffering following upsetting or angry events.
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Randomized Controlled Trial
Intrathecal glycine for pain and dystonia in complex regional pain syndrome.
Since glycinergic neurotransmission plays an important inhibitory role in the processing of sensory and motor information, intrathecal glycine (ITG) administration may be a potential therapy for both pain and movement disorders in patients with complex regional pain syndrome (CRPS). Aims of the current study, which is the first report on ITG in humans, were to evaluate its safety and efficacy. ITG treatment during 4 weeks was studied in CRPS patients with dystonia in the period before they received intrathecal baclofen treatment. ⋯ Although there was a trend to worsening on the CGI and PGI during ITG treatment, there were no significant differences between ITG and placebo treatment in any of the outcomes. ITG given over 4 weeks was ineffective for pain or dystonia in CRPS. Although no serious adverse events occurred, further studies are required to rule out potential neurotoxicity of ITG.
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Randomized Controlled Trial
Randomized controlled trial of an Internet-delivered family cognitive-behavioral therapy intervention for children and adolescents with chronic pain.
Cognitive-behavioral therapy (CBT) interventions show promise for decreasing chronic pain in youth. However, the availability of CBT is limited by many factors including distance to major treatment centers and expense. This study evaluates a more accessible treatment approach for chronic pediatric pain using an Internet-delivered family CBT intervention. ⋯ There were no significant group differences in parental protectiveness or child depressive symptoms post-treatment. Internet treatment was rated as acceptable by all children and parents. Findings support the efficacy and acceptability of Internet delivery of family CBT for reducing pain and improving function among children and adolescents with chronic pain.