European journal of pain : EJP
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Pain models are commonly used in drug development to demonstrate analgesic activity in healthy subjects and should therefore not cause long-term adverse effects. The ultraviolet B (UVB) model is a model for inflammatory pain in which three times the minimal erythema dose (3MED) is typically applied to induce sensitization. Based on reports of long-lasting postinflammatory hyperpigmentation (PIH) associated with 3MED, it was decided to investigate the prevalence of PIH among subjects who were previously exposed to 3MED at our research centre. In addition, re-evaluation of the UVB inflammation model using a reduced exposure paradigm (2MED) was performed in healthy subjects. ⋯ Postinflammatory hyperpigmentation is an unwanted long-term side effect associated with the UVB inflammation model using the 3× minimal erythema dose (3MED) paradigm. In contrast, using a 2MED paradigm results in hyperalgesia that is stable for 36 hr and has a lower risk of inducing postinflammatory hyperpigmentation.
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Long-term opioid prescribing for musculoskeletal pain is controversial due to uncertainty regarding effectiveness and safety. This study examined the risks of a range of adverse events in a large cohort of patients prescribed long-term opioids using the UK Clinical Practice Research Datalink. ⋯ Long-term opioid use is associated with serious adverse events such as major trauma, addiction and overdose. The risk increases with higher opioid doses. Opioid prescribing should be reviewed before long-term use becomes established, and periodically thereafter to assess ongoing effectiveness.
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Estimation of a patient's pain may have a considerable impact on the level of care that patient receives. Many studies have shown that contextual factors may influence an observer's pain estimation. Here, we investigate the effect of an observer's impression of a person in pain and justification of his/her pain on the observer's pain estimation, tendency to help and perceived empathy. ⋯ Observers' estimation of pain, perceived empathy and tendency to help biases by their understanding of the characteristics of the person in pain. In clinical settings, these biases may influence the quality of care and well-being of patients. Understanding the underlying mechanisms of these biases can help us improve the quality of care and control the effect of prejudices on pain assessment.
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Primary dysmenorrhoea (PDM), characterized as menstrual pain without pelvic pathology, is associated with pain-related negative mood and hormone fluctuations. Previous studies strongly supported the link between pain and negative mood in affected individuals; however, it remains largely unknown in patients with PDM. ⋯ Our findings provide further evidence of amygdala-related abnormalities, which may be associated with pain-related affective distress and hormonal fluctuations in women with PDM, and complement the brain mechanism investigations for the pathophysiology of PDM.
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γ-Aminobutyric acid type A (GABAA ) receptors containing the α6 subunit are located in trigeminal ganglia, and their reduction by small interfering RNA increases inflammatory temporomandibular and myofascial pain in rats. We thus hypothesized that enhancing their activity may help in neuropathic syndromes originating from the trigeminal system. Here, we performed a detailed electrophysiological and pharmacokinetic analysis of two recently developed deuterated structurally similar pyrazoloquinolinone compounds. ⋯ Results obtained in two protocols of chronic constriction injury of the infraorbital nerve in rats dosed intraperitoneally with DK-I-56-1 during 14 days after surgery or with DK-I-56-1 or DK-I-87-1 during 14 days after trigeminal neuropathy were already established, demonstrated that DK-I-56-1 but not DK-I-87-1 significantly reduced the hypersensitivity response to von Frey filaments. SIGNIFICANCE: Neuropathic pain induced by trigeminal nerve damage is poorly controlled by current treatments. DK-I-56-1 that positively modulates α6 GABAA receptors is appropriate for repeated administration and thus may represent a novel treatment option against the development and maintenance of trigeminal neuropathic pain.