Pain
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Clinical Trial
Influence of repeated painful procedures and sucrose analgesia on the development of hyperalgesia in newborn infants.
This study determined the effects of cumulative exposure to painful needle procedures and sucrose analgesia on the development of remote hyperalgesia in newborn infants, defined as an increase in response to a normally painful stimulus at a site distal from the site of injury. One-hundred and twenty healthy newborns and 120 healthy newborn infants of diabetic mothers equally randomized to sucrose analgesia or placebo prior to all needle procedures in the first two days after birth were divided into two exposure groups according to number of needle procedures they had undergone [high (> or =5) or low (< or =4)] using the median cut-off technique. Compared to the low exposure group, infants in the high exposure group had a higher pain response during a subsequent venipuncture distal to the site of previous injury, assessed by the Premature Infant Pain Profile (PIPP) [7.1 vs. 8.4; p=0.012] and Visual Analog Scale (VAS) [2.5 cm vs. 3.2 cm; p=0.047], and a trend for longer cry duration [25.7 s vs. 33.8 s; p=0.171]. ⋯ Sucrose reduced PIPP, VAS, and cry duration scores during venipuncture, but did not prevent hyperalgesia (p>0.05). There was a preponderance of infants of diabetic mothers in the high exposure group; however, the analysis did not demonstrate this to be a confounding factor. In conclusion, sucrose analgesia for repeated painful procedures in the first day of life does not prevent development of remote hyperalgesia in newborns.
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Randomized Controlled Trial
Placebo analgesia induced by social observational learning.
Although it has long been known that psychosocial factors play a crucial role in placebo responses, no attempt has been made to understand if social observation shapes the placebo analgesic effect. To address this question, we compared placebo analgesia induced through social observation (Group 1) with first-hand experience via a typical conditioning procedure (Group 2) and verbal suggestion alone (Group 3). In Group 1, subjects underwent painful stimuli and placebo treatment after they had observed a demonstrator (actually a simulator) showing analgesic effect when the painful stimuli were paired to a green light. ⋯ We found that observing the beneficial effects in the demonstrator induced substantial placebo analgesic responses, which were positively correlated with empathy scores. Moreover, observational social learning produced placebo responses that were similar to those induced by directly experiencing the benefit through the conditioning procedure, whereas verbal suggestions alone produced significantly smaller effects. These findings show that placebo analgesia is finely tuned by social observation and suggest that different forms of learning take part in the placebo phenomenon.
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Randomized Controlled Trial
A randomized trial of a tailored barriers intervention for Cancer Information Service (CIS) callers in pain.
Cancer pain management can be improved by overcoming patients' attitudinal barriers to reporting pain and using analgesics. A simple cost-effective barriers intervention designed to reach a large number of persons with cancer has not yet been tested. Such an intervention should be tested against barriers' assessment-alone, as well as no-treatment control. ⋯ At follow-up the TBI group had significantly lower attitudinal barriers scores compared to assessment-alone and control, but the groups did not differ on the pain outcome variables. TBI and assessment-alone had similar cost effectiveness. The TBI needs to be strengthened to achieve reductions in pain severity.
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Clinical Trial
Similar itch and nociceptive sensations evoked by punctate cutaneous application of capsaicin, histamine and cowhage.
Itch evoked by cowhage or histamine is reduced or blocked by capsaicin desensitization, suggesting that pruriceptive neurons are capsaicin-sensitive. Topical capsaicin can evoke both nociceptive sensations and itch, whereas intradermal injection of capsaicin evokes only burning pain. To dissociate the pruritic and nociceptive sensory effects caused by the chemical activation of sensory neurons, chemicals were applied in a punctiform manner to the skin of the forearm using individual, heat-inactivated cowhage spicules treated with various concentrations of capsaicin (1-200 mg/ml) or histamine (0.01-100 mg/ml). ⋯ Each type of spicule also produced comparable areas of dysesthesias (enhanced mechanically evoked itch or pain) and/or skin reactions (wheal and/or flare) in surrounding skin, though inconsistently. The incidence of flare was greater in response to histamine than to capsaicin or cowhage. These results suggest the possibility that capsaicin, histamine and cowhage activate common peripheral or central neural mechanisms that mediate pruritic sensations and associated dysesthesias.
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We used a large medical insurance claims database to identify three groups: chronic opioid use (>180 therapeutic days, N=3726); acute opioid use (<10 therapeutic days, N=37,108); and a non-opioid group (N=337,366) who filed at least one insurance claim but none for opioids. Our results showed that although chronic opioid users represented only 0.65% of the total population, they filed 4.56% of all insurance claims, used 45% of all opioid analgesics and had much more physical and psychiatric co-morbidity than the acute opioid or non-opioid samples. ⋯ Moreover, our data suggest that opioids were often used for conditions in which they are generally not indicated (e.g. arthritis and headaches) or contraindicated by co-existing physical ailments (COPD). Finally, we conclude that adherence to the WHO analgesic ladder and other pain treatment guidelines was relatively infrequent: first, opioid extended release preparations which are ideally suited for chronic pain were used only in one in four patients; and, second, the selection of a weak (propoxyphene, codeine, and tramadol) or strong opioid (e.g. morphine and oxycodone) seemed to be driven by numerous factors not necessarily related to the intensity or duration of pain.