Pain
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Randomized Controlled Trial Clinical Trial
Concentration-effect relationship of intravenous alfentanil and ketamine on peripheral neurosensory thresholds, allodynia and hyperalgesia of neuropathic pain.
Both mu opioid agonists and N-methyl-D-aspartate (NMDA) receptor antagonists are implicated in the regulation of neuropathic pain in post-nerve injury preclinical pain models. This study characterizes the effects of intravenously infused alfentanil (a mu-receptor agonist) and ketamine (an NMDA-receptor antagonist) on human neuropathic pain states, characterized by allodynia and hyperalgesia. Using diphenhydramine as the placebo, alfentanil and ketamine infusions were given in a randomized double-blind fashion 1 week apart via a computer-controlled infusion (CCI) pump that was programmed to target plasma levels of alfentanil at 25, 50 and 75 ng/ml and ketamine at 50, 100 and 150 ng/ml. ⋯ Therefore, clinical utilization of opioids with careful titration may be beneficial in post-nerve injury patients with partial deafferentation. With the absence of significant CNS side effects, the ketamine infusion not only demonstrated the well-documented spinal cord mechanism of the NMDA receptor, but the result of the current study also suggests that a peripheral mechanism of NMDA receptor may exist. The relationship between central sensitization and regulation of peripheral NMDA-receptor expression requires further investigation.
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Randomized Controlled Trial Clinical Trial
Treatment of severe pain from osteoarthritis with slow-release tramadol or dihydrocodeine in combination with NSAID's: a randomised study comparing analgesia, antinociception and gastrointestinal effects.
Opioids are increasingly used in the treatment of chronic non-malignant pain. The aim of this open-label, randomised, parallel group study was to compare analgesia and side-effects of two commonly used opioid analgesics, tramadol and dihydrocodeine, in long-acting formulations in 60 osteoarthritis patients with strong pain despite NSAID's. Dose titration based on effect was performed with the respective immediate release solutions given additionally to tramadol 100 mg bid and dihydrocodeine 60 mg bid during the first 4 days of the 1 month treatment. ⋯ We conclude rapid pain relief was achieved with both long-acting tramadol and dihydrocodeine with NSAID's in strong osteoarthritis pain. Minimal dose titration was required and side-effects were minor. Tramadol interfered less with intestinal function and showed greater antinociceptive action.
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Randomized Controlled Trial Clinical Trial
A cognitive-behavioral return-to-work program: effects on pain patients with a history of long-term versus short-term sick leave.
A cognitive-behavioral return-to-work focused program was evaluated in a randomized controlled design, and the effects were compared between two groups of women with musculoskeletal pain. One group of patients (n=36) had a history of long-term sick leave (>12 months) at the start of the program and the other (n=36) had a history of short-term sick leave (2-6 months). The outpatient treatment program, conducted by a psychologist, included 12 sessions with the primary aim to help the patients return-to-work. ⋯ The results showed that the cognitive-behavioral return-to-work program was more effective than the treatment-as-usual control condition in reducing the number of days on sick leave for patients on short-term sick leave, but not for patients on long-term sick leave. The treatment program also helped the patients on short-term sick leave to increase their ability to control and decrease pain and to increase their general activity level compared to the control condition. These results underscore the need for an early return-to-work focused rehabilitation to prevent long-term sick leave and disability.
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Recent research indicates that people who are fearful of pain tend to report more negative pain experiences. It also seems that attentional mechanisms may be particularly important in the perception of painful stimuli, especially amongst pain fearful individuals. Drawing on a paradigm used to examine biased cognitive processes in the emotional disorders, the current study investigated whether the fear of pain would be related to a greater selective attentional bias in favour of pain-related stimuli. ⋯ No group differences were found for either social threat or positive stimuli. These results indicate that one reason why those with a high fear of pain are particularly susceptible to negative pain experiences could be due to biased attentional processes. Suggestions for cognitive interventions designed to reduce such biases are discussed, as are directions for future research.
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Meta Analysis
Seeking a simple measure of analgesia for mega-trials: is a single global assessment good enough?
We sought to investigate the potential of using a simple global estimation ('How effective do you think the treatment was?') as a measure of efficacy by comparing it with at least 50%maxTOTPAR (at least 50% of the maximum possible pain relief) in acute pain studies. One hundred and fifty randomized, double-blind trials included in 11 systematic reviews of single dose, oral analgesics for postoperative pain were used as a source of data. The relationship between the proportion of patients reporting the top two or three values on a five-point global scale and the proportion with at least 50%maxTOTPAR was investigated. ⋯ Individual patient data were also used from four randomized, placebo-controlled, double-blind trials in postoperative pain. The frequency distribution for %maxTOTPAR was plotted for patients reporting each of the five categories on the global scale. A global assessment provides similar measures of analgesic efficacy as TOTPAR derived from hourly measurements, but the effects of adverse effects have yet to be understood.