Articles: hyperalgesia.
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Reg Anesth Pain Med · May 2008
Comparative StudyThe effect of opioid dose and treatment duration on the perception of a painful standardized clinical stimulus.
The concept of opioid-induced hyperalgesia has recently gained prominence as a contributing factor for opioid tolerance and long-term treatment failure. But whereas the preclinical data for this phenomenon are strong, the mixed clinical data derive primarily from experimental pain models conducted in volunteers and heroin addicts, and nonstandardized clinical stimuli, e.g., surgery. The primary objective of this study is to delineate the effect of opioid dose and treatment duration on pain intensity and unpleasantness ratings following a standardized clinical pain stimulus. ⋯ The results of this study bolster preclinical and experimental pain models demonstrating enhanced pain perception in subjects receiving opioid therapy. This simple clinical model may provide a useful tool in examining opioid-induced hyperalgesia.
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Opioid-induced hyperalgesia (OIH) refers to a phenomenon whereby opioid administration results in a lowering of pain threshold, clinically manifest as apparent opioid tolerance, worsening pain despite accelerating opioid doses, and abnormal pain symptoms such as allodynia. ⋯ Despite initial skepticism and reservations, the phenomenon of OIH in humans is now accepted a clinical reality and a challenge faced by anesthesiologists, intensivists, pain specialists, and other workers in a diverse range of settings from perioperative care to palliative care medicine.
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Migraine is known to be associated to particular psychological features. Cutaneous allodynia is a painful sensation or discomfort induced by a non-noxious stimulus, and is a frequent complaint during migraine attacks. The aim of this study was to compare the personality profile of allodynic and non-allodynic migraineurs to identify possible relationships between psychological aspects and the presence of allodynia. ⋯ No significant difference was found between the two groups in any area of the personality profile. The psychological profile seems not to affect the presence/absence of cutaneous allodynia in migraine patients. This reinforces the hypothesis that allodynia is a "somatic" symptom, not modified by psychological aspects.
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Neutrophil migration into tissues is involved in the genesis of inflammatory pain. Here, we addressed the hypothesis that the effect of CXC chemokines on CXCR1/2 is important to induce neutrophil migration and inflammatory hypernociception. ⋯ CXCR1/2 mediates neutrophil migration and is involved in the cascade of events leading to inflammatory hypernociception. In addition to modifying fundamental pathological processes, non-competitive allosteric inhibitors of CXCR1/2 may have the additional benefit of providing partial relief for pain and, hence, may be a valid therapeutic target for further studies aimed at the development of new drugs for the treatment of rheumatoid arthritis.