Pain
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Patient adjustment to chronic pain is well known to be influenced by the spouse and his or her response to patient expressions of pain. However, these responses do not occur in a vacuum, and the aim of the present study was to investigate patient-spouse interactions in chronic pain in detail. Ninety-five patient-spouse dyads completed questionnaires relating to mood, marital satisfaction and communication, and 80 couples also took part in semi-structured interviews. ⋯ Spouse perceived frequency of pain talk was not related to spouse marital satisfaction. There were no gender differences in marital satisfaction. The results of this study challenge some of the assumptions that have been held regarding chronic pain patient-spouse interactions.
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Chronic pain can dominate all concerns for individuals suffering with it, leaving much of their time focused on trying to reduce pain rather than living their life, as they would most want to do, according to their values. The purpose of this study was to examine these processes, the degree of success patients have in following their values as guides for their actions, and relations between values-based action and other aspects of daily functioning. For this study we designed a brief inventory of patient values in domains of family, intimate relations, friends, work, health, and growth or learning. ⋯ Significant correlations of overall success with measures of avoidance and acceptance of pain supported the validity of scores from the values measure. Success in living according to values was correlated with measures of disability, depression, and pain-related anxiety. Regression analysis showed that success at living according to values predicted variance in functioning independent of acceptance of pain, supporting its incremental utility in a contextual analysis of chronic pain and its potential importance in treatment for chronic pain.
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Comparative Study
Involvement of the TTX-resistant sodium channel Nav 1.8 in inflammatory and neuropathic, but not post-operative, pain states.
Antisense (AS) oligodeoxynucleotides (ODNs) targeting the Nav 1.8 sodium channel have been reported to decrease inflammatory hyperalgesia and L5/L6 spinal nerve ligation-induced mechanical allodynia in rats. The present studies were conducted to further characterize Nav 1.8 AS antinociceptive profile in rats to better understand the role of Nav 1.8 in different pain states. Consistent with earlier reports, chronic intrathecal Nav 1.8 AS, but not mismatch (MM), ODN decreased TTX-resistant sodium current density (by 60.5+/-10.2% relative to MM; p<0.05) in neurons from L4 to L5 dorsal root ganglia and significantly attenuated mechanical allodynia following intraplantar complete Freund's adjuvant. ⋯ Finally, Nav 1.8 AS, but not MM, ODN treatment produced a small but significant attenuation of acute noxious mechanical sensitivity in naïve animals (17.6+/-6.2% effect, p<0.05 vs. MM). These data demonstrate a greater involvement of Nav 1.8 in frank nerve injury and inflammatory pain as compared to acute, post-operative or chemotherapy-induced neuropathic pain states.
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Osteoarthritis (OA) is a debilitating disease in which primarily weight-bearing joints undergo progressive degeneration. Despite the widespread prevalence of OA in the adult population, very little is known about the factors responsible for the generation and maintenance of OA pain. Vasoactive intestinal peptide (VIP) was identified in the synovial fluid of arthritis patients nearly 20 years ago and the aim of this study was to examine whether VIP could be involved in the generation of OA pain. ⋯ Treatment of OA knees with a single injection of VIP6-28 diminished hindlimb incapacitance while increasing paw withdrawal threshold. This study showed for the first time that peripheral application of VIP causes increased knee joint allodynia and secondary hyperalgesia. Furthermore, antagonists that inhibit VIP activity may prove beneficial in the alleviation of OA pain.
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Randomized Controlled Trial Comparative Study
A comparative study of oxycodone and morphine in a multi-modal, tissue-differentiated experimental pain model.
Visceral pain can be difficult to treat with classical mu-opioid agonists and it has been suggested to use opioids with distinct pharmacological profiles. In animal experiments, oxycodone has shown different effects compared to morphine, and clinical observations have shown that oxycodone may occasionally be superior to, e.g., morphine in the treatment of visceral pain. In the current study, we randomised 24 healthy subjects to treatment with either morphine (30 mg), oxycodone (15 mg) or placebo in a crossover study. ⋯ Morphine and oxycodone were equipotent in pain modulation of the skin and muscles, but oxycodone had superior analgesic effect to both morphine and placebo on the mechanical (P<0.001) and thermal (P<0.001) stimulations of the oesophagus. In conclusion, the multi-modal and tissue-differentiated pain model could link findings from animal experiments to clinical findings. A different pharmacological profile of oxycodone compared to that of morphine was shown, and thus oxycodone may be a useful alternative to morphine in the treatment of visceral pain syndromes.