European journal of pain : EJP
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A growing field of investigation into social justice cognitions and pain suggests perceived injustice has a negative impact on pain, but little is known about individual variation in the impact of a perceived injustice. One published study found that individuals with a strong rather than a weak just-world belief reported greater pain from the cold pressor task after experiencing a perceived injustice, but an overt measure of perceived unfairness is needed to investigate this relationship. ⋯ Recalled personal injustice unrelated to one's current pain experience had a negative impact on pain and anxiety associated with the cold pressor task. These findings indicate that intervention development should be cognizant of the role of everyday injustices and not just those related to pain, on the pain experience. WHAT DOES THIS STUDY ADD?: This study shows that, independent of just-world beliefs, perceived unfairness associated with a recalled injustice unrelated to pain has a negative impact on the experience of acute pain.
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Randomized Controlled Trial Multicenter Study
Direct conversion from tramadol to tapentadol prolonged release for moderate to severe, chronic malignant tumour-related pain.
A recent randomized-withdrawal, active- and placebo-controlled, double-blind phase 3 study showed that tapentadol prolonged release (PR) was effective and well tolerated for managing moderate to severe, chronic malignant tumour-related pain in patients who were opioid naive or dissatisfied with current treatment (Pain Physician, 2014, 17, 329-343). This post hoc, subgroup analysis evaluated the efficacy and tolerability of tapentadol PR in patients who previously received and were dissatisfied with tramadol for any reason and who had a pain intensity ≥5 (11-point numerical rating scale) before converting directly to tapentadol PR. ⋯ Results of this subgroup analysis indicate that patients with cancer pain could safely switch from prior treatment with the weak centrally acting analgesic tramadol directly to the strong centrally acting analgesic tapentadol PR, for an improved analgesic therapy for severe pain. WHAT DOES THIS STUDY ADD?: Results of this post hoc analysis show that patients who had received prior tramadol therapy could switch directly to tapentadol PR, with the majority (˜70%) experiencing improved efficacy.
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The co-occurrence of chronic pain and post-traumatic stress symptoms (PTSS) and post-traumatic stress disorder (PTSD) has gained increasing research attention. Studies on associations among pain and PTSS or PTSD in youth have largely been conducted in the context of acute injury or trauma. Less is known about the risk for co-occurrence with paediatric chronic pain. In this review, we (1) propose a conceptual framework to outline factors salient during childhood that may be associated with symptom severity, co-occurrence and mutual maintenance, (2) present relevant literature on PTSS in youth with acute and chronic pain and identify research gaps and (3) provide recommendations to guide paediatric research examining shared symptomatology. ⋯ Our new developmentally informed framework highlights individual symptoms and shared contextual factors that are important when examining potential associations among paediatric chronic pain and PTSS. Future studies should consider bidirectional and mutually maintaining associations, which will be aided by prospective, longitudinal designs. WHAT DOES THIS REVIEW ADD?: This review presents relevant literature on pain and PTSS in youth and proposes a conceptual framework to examine factors salient during childhood that may be associated with symptom severity, comorbidity and mutual maintenance of chronic pain and PTSS in paediatric populations. We highlight dynamic factors that may change across children's development and provide recommendations to guide paediatric research examining potential associations among PTSS and chronic pain.
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Randomized Controlled Trial
A randomized phase I trial evaluating the effects of inhaled 50-50% N2 O-O2 on remifentanil-induced hyperalgesia and allodynia in human volunteers.
Opioids are known to relieve pain, and also aggravate pre-existing hyperalgesia. In animal studies, the N-methyl-d-aspartate-receptor antagonist nitrous oxide (N2 O) was able to prevent hyperalgesia. The present study evaluated the effect of N2 O on hyperalgesia after remifentanil infusion in healthy volunteers. ⋯ Nitrous oxide significantly reduced hyperalgesia, allodynia and pain intensity aggravated after remifentanil administration in a human volunteer model. WHAT DOES THIS STUDY ADD?: This study brings the evidence that N2 O reduces the remifentanil aggravated secondary hyperalgesia in human volunteers exposed to a well-known model of electrical pain. N2 O was able to oppose the hyperalgesia, the allodynia and the pain intensity consecutive to remifentanil use in this specific pain model.
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At high concentration, the TRPV-1 agonist capsaicin de-sensitizes nociceptors and reduces the intra-epidermal nerve density. ⋯ Axonal nociceptor function assessed by electrical excitability tests supplements threshold tests of nociceptive endings. The differential analgesic effects of 8% capsaicin patches may be attributed to the kinetics of capsaicin and the different depth of nociceptive nerve fibres, yet, the time course does not match the long-lasting analgesia observed in neuropathic pain patients treated with the same patch. WHAT DOES THIS STUDY ADD?: Axonal nociceptor function assessed by supra-threshold electrical excitability tests did not coincide with capsaicin-induced transduction changes supplementing threshold measures of terminal nociceptor endings. Threshold measurements do not reflect the sustained effect of pain relief seen in neuropathic pain patients. Capsaicin-sensitive nociceptors responsible for spontaneous pain are either not specifically tested with currently available sensory stimulation protocols or have higher capsaicin sensitivity or slower recovery under neuropathic conditions.