Articles: hyperalgesia.
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The hyperalgesic effects of long-term opioid use in community-dwelling adults with chronic pain have not been widely reported. Therefore, the primary aim of this study was to determine the associations between opioid use and heat pain (HP) perception in a sample of community-dwelling adults with chronic pain. The study cohort involved 187 adults (85 opioid and 102 nonopioid) with chronic pain consecutively admitted to an outpatient interdisciplinary pain treatment program. ⋯ In univariable (P = 0.019) and multiple variable (P = 0.003) linear regression analyses (adjusted for age, sex, body mass index, work status, pain diagnosis, pain severity, depression, and pain catastrophizing), opioid use was associated with lower (more hyperalgesic) nonstandardized values of HP 5-0.5. Similarly, in univariable (P = 0.004) and multiple variable (P = 0.011) linear regression analyses (adjusted for work status, pain diagnosis, pain severity, depression, and pain catastrophizing), opioid use was associated with lower standardized values of HP 5-0.5. In this sample of community-dwelling adults, these observations suggest that long-term opioid use was associated with hyperalgesia independent of other clinical factors known to influence HP perception.
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Randomized Controlled Trial
Altered thermal grill response and paradoxical heat sensations after topical capsaicin application.
The thermal grill illusion, where interlaced warm and cold bars cause an unusual burning sensation, and paradoxical heat sensations (PHS), where cold is perceived as warm when alternating warm and cold, are examples of a complex integration of thermal sensations. Here, we investigated the effect of sensitization of heat-sensitive neurons on cold and warm integration. We examined thermal thresholds, PHS, and warm, cold, and pain sensations to alternating cold (10°C) and warm (40°C) bars (the thermal grill [TG]) in the primary area (application site) after topical application with capsaicin and vehicle control (ethanol) on the volar forearms in randomized order in 80 healthy participants. ⋯ Paradoxical heat sensation was only seen in 3 participants after control application but in 19 participants after capsaicin. Those with PHS after capsaicin application had higher detection thresholds to both cold and warm than those without PHS, but there was no difference in thermal pain threshold. These results suggest that a complex cross talk among several cold and warm sensitive pathways shapes thermal perception.
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Randomized Controlled Trial
Evaluation of the effect of ketamine on remifentanil-induced hyperalgesia: a double-blind, randomized study.
Opioids are associated with hyperalgesia that can reduce their analgesic effect. The aim of this study was to determine whether the addition of ketamine reduces remifentanil-induced hyperalgesia; improves its analgesic effect; and alters interleukin 6 (IL-6), IL-8, and IL-10 levels. ⋯ It was not possible to demonstrate that the addition of ketamine (5 μg/kg per minute) is effective in preventing or reducing remifentanil-induced postoperative hyperalgesia in laparoscopic cholecystectomy.
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Clinical rheumatology · Jun 2015
Chronic pain in patients with the hypermobility type of Ehlers-Danlos syndrome: evidence for generalized hyperalgesia.
Chronic widespread pain is highly present in patients with the Ehlers-Danlos syndrome hypermobility type (EDS-HT), but up to now, evidence for generalized hyperalgesia is lacking. The aim of this study is to investigate whether pressure pain thresholds (PPTs) at both symptomatic and asymptomatic body areas differ in EDS-HT patients compared to healthy subjects. Twenty-three women with EDS-HT and 23 gender- and age-matched healthy controls participated. ⋯ In half of the patient group, a predominantly neuropathic pain component was likely present. This study provides evidence for the existence of hyperalgesia even in asymptomatic areas (generalized secondary hyperalgesia). The generalized hyperalgesia may represent the involvement of a sensitized central nervous system, which inquires an adapted pain management for this patient group.
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Opioid analgesics have become a cornerstone in the treatment of moderate to severe pain, resulting in a steady rise of opioid prescriptions. Subsequently, there has been a striking increase in the number of opioid-dependent individuals, opioid-related overdoses, and fatalities. Clinical use of opioids is further complicated by an increasingly deleterious profile of side effects beyond addiction, including tolerance and opioid-induced hyperalgesia (OIH), where OIH is defined as an increased sensitivity to already painful stimuli. ⋯ Several substrates have emerged as potential modulators of OIH, including the N-methyl-D-aspartate and γ-aminobutyric acid receptors, and most notably, the innate neuroimmune system. This review summarizes the neurobiology of OIH in the context of clinical treatment; specifically, we review evidence for several pathways that show promise for the treatment of pain going forward, as prospective adjuvants to opioid analgesics. Overall, we suggest that this paradoxical state be considered an additional target of clinical treatment for chronic pain.