Pain
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Randomized Controlled Trial Clinical Trial
Interaction of a combination of morphine and ketamine on the nociceptive flexion reflex in human volunteers.
Experimental studies in animals have suggested that a combination of morphine and N-methyl-D-aspartate (NMDA) receptor antagonists may have additive or synergistic analgesic effects. To further study the nature of the interaction between these two classes of analgesic agents, we analyzed the effects of morphine, ketamine and their combination on electrophysiological recordings of the nociceptive flexion RIII reflex in 12 healthy volunteers. Morphine (0.1 mg/kg), ketamine (0.1 mg/kg followed by 4 microg/kg/min) or their combination were administered intravenously according to a double-blind, placebo controlled and cross-over design. ⋯ The wind-up of the RIII reflex and painful sensation was not significantly altered after the injection of placebo, ketamine, morphine or their combination. In conclusion, the present electrophysiological results in humans demonstrate a synergistic interaction between morphine and ketamine, which tends to confirm the interest of using this type of combination in the clinical context. The differential effects observed on the recruitment curve and wind-up indicate, however, that the mechanisms of the interaction between opiates and NMDA receptor antagonists are not univocal but depend on the modality of activation of the nociceptive afferents.
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This study examined the degree of correspondence between lung cancer patients and their family caregivers in their perceptions of the patients' self-efficacy for managing pain and other symptoms of lung cancer, and the association of this correspondence to demographic, disease, and psychosocial variables. Thirty patients who were newly diagnosed with lung cancer and their primary family caregivers completed telephone interviews assessing the patient's symptoms, the patient's self-efficacy for managing symptoms, the quality of the relationship between the patient and caregiver, patient and caregiver psychological distress, and caregiver strain. ⋯ Caregivers were about evenly split in their tendency to overestimate versus underestimate the patient's self-efficacy. A poorer quality of relationship between the caregiver and the patient (as rated by the patient), high levels of patient-rated symptoms, and high levels of caregiver strain were associated with caregivers overestimating patient self-efficacy.
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Little research has examined the role of patient cognitive and behavioral responses, including catastrophizing, in adjustment to chronic pain associated with spinal cord injury (SCI). The objective of this study was to examine the associations of catastrophizing and specific pain coping strategies with pain intensity, psychological distress, and pain-related disability among individuals with chronic pain and SCI, after controlling for important demographic and SCI-related variables that might affect outcomes. Participants in this study were 174 community residents with SCI and chronic pain who completed a mailed questionnaire that included the SF-36 Mental Health scale, Coping Strategies Questionnaire, and Graded Chronic Pain Scale. ⋯ The coping and catastrophizing scales accounted for an additional 30% of the variance in psychological distress (P<0.001) and 11% of the variance in pain-related disability (P<0.001), after controlling for pain intensity and demographic and SCI variables. Catastrophizing, but not any other single pain coping strategy, was consistently strongly and independently associated with the outcome measures. Potentially, the assessment and treatment of catastrophizing may reduce psychological distress and pain-related disability among individuals with chronic pain and SCI.
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The reproducibility of both the conscious experience of pain and the reproducibility of psychophysical assessments of pain remain critical, yet poorly characterized factors in pain research and treatment. To assess the reproducibility of both the pain experience and two methods of pain assessment, 15 subjects evaluated experimental heat pain during four weekly sessions. In each session, both brief (5s) and prolonged (90s) heat stimuli were utilized to determine effects of stimulus duration on reproducibility. ⋯ However, the VAS was significantly more sensitive to small differences in perceived pain intensity and pain unpleasantness, and did not exhibit some of the order effects present with the VDS. Taken together, these results indicate that the reproducibility of psychophysical ratings of pain can be maximized: (1) by averaging responses to multiple, brief stimuli; (2) by providing subjects with a training period distinct from the study period; and (3) by ensuring that interpretation of scale parameters remains constant over time. Thus, although the experiences of both experimental and clinical pain are highly variable, pain assessment procedures can be structured to minimize session-to-session variability.
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Randomized Controlled Trial Clinical Trial
Phase III evaluation of nortriptyline for alleviation of symptoms of cis-platinum-induced peripheral neuropathy.
Tricyclic antidepressants have been reported to relieve the paresthesiae associated with peripheral neuropathies of many etiologies. We designed a randomized, double-blind, placebo-controlled, crossover trial to establish the efficacy of nortriptyline in the treatment of cis-diamminedichloroplatinum (CDDP)-induced paresthesiae. The study included 51 evaluable patients with CDDP-induced peripheral neuropathy and painful paresthesiae. ⋯ In summary, nortriptyline failed to demonstrate strong evidence of any effect on paresthesia or pain. The presence of a potential effect which appeared in the second period of the crossover design is questionable due to the observed carryover effect. Cross-validation sensitivity analysis of results support the conclusion that nortriptyline provides modest improvement at best over placebo in terms of chemotherapy-related neuropathy.