Pain
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Visceral pain processing is abnormal in a majority of irritable bowel syndrome (IBS) patients. Aberrant endogenous nociceptive modulation and anticipation are possible underlying mechanisms investigated in the current study. Twelve IBS patients and 12 matched healthy controls underwent brain fMRI scanning during the following randomised stimuli: sham and painful rectal distensions by barostat without and with simultaneous activation of endogenous descending nociceptive inhibition using ice water immersion of the foot for heterotopic stimulation. ⋯ In conclusion, IBS patients showed dysfunctional endogenous inhibition of pain and concomitant aberrant activation of brain areas involved in pain processing and integration. Anticipation of rectal pain was associated with different brain activation patterns in IBS involving multiple interoceptive, homeostatic, associative and emotional areas, even though pain scores were similar during sham distension. The aberrant activation of endogenous pain inhibition appears to involve circuitry relating to anticipation as well as pain processing itself.
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Neuropathic pain is a major clinical problem unresolved by available therapeutics. Spinal cord glia play a pivotal role in neuropathic pain, via the release of proinflammatory cytokines. Anti-inflammatory cytokines, like interleukin-10 (IL-10), suppress proinflammatory cytokines. ⋯ This supports that spinal proinflammatory cytokines are important in both the initiation and maintenance of neuropathic pain. Importantly, pDNA-IL-10 gene therapy reversed mechanical allodynia induced by CCI, returning rats to normal pain responsiveness, without additional analgesia. Together, these data suggest that intrathecal IL-10 gene therapy may provide a novel approach for prolonged clinical pain control.
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Review Meta Analysis
Gabapentin and postoperative pain--a systematic review of randomized controlled trials.
The objective of this systematic review was to evaluate the efficacy and tolerability of perioperative gabapentin administration for the control of acute postoperative pain. We searched Medline (1966-2006), the Cochrane Library (2006), Scopus, CINAHL and bibliographies from clinical trials and review articles. We included randomized controlled trials (RCTs) comparing gabapentin with inactive controls in surgical patients. ⋯ Cumulative 24 h opioid consumption was also lower (WMD, -7.25 mg). Gabapentin was associated with an increased risk of sedation (Peto OR 3.86; 95% CI 2.50-5.94) but less opioid-related side effects such as vomiting (Peto OR 0.58; 95% CI 0.39-0.86) and pruritus (Peto OR 0.27; 95% CI 0.10-0.74). In conclusion, gabapentin has an analgesic and opioid-sparing effect in acute postoperative pain management when used in conjunction with opioids.
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Randomized Controlled Trial
Differential sensitivity of three experimental pain models in detecting the analgesic effects of transdermal fentanyl and buprenorphine.
This is the first randomized controlled trial that tests the analgesic efficacy of transdermally delivered opioids in healthy volunteers and that assesses the sensitivity of different experimental pain tests to detect analgesia in this setting. Transdermal application of the full agonist fentanyl (TDF: 12.5 or 25 microg/h) and the partial agonist buprenorphine (TDB: 35 microg/h) was compared in three experimental models of acute pain (heat pain, painful electrical stimulation, cold pressor) in a double-blind, randomized, placebo-controlled, 4-arm crossover study with 20 healthy subjects (15 men, 5 women). Patches were administered for 72 h and pain levels measured at baseline and 24 and 72 h, with an 11-day wash-out. ⋯ We conclude that the cold pressor test was most sensitive to analgesic effects in healthy subjects and that a transdermal dose of 12.5 microg/h fentanyl achieved significant pain reduction compared with placebo. Subjects experienced opioid-typical AEs including dizziness, nausea and vomiting. No serious AEs occurred.
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Randomized Controlled Trial
Efficacy and safety of acupuncture for chronic uncomplicated neck pain: a randomised controlled study.
Chronic neck pain is highly prevalent. To determine the efficacy and safety of acupuncture, in comparison with transcutaneous nerve stimulation-placebo (TENS-placebo) in the treatment of chronic uncomplicated neck pain, a single blind prospective study was designed, to be carried out at a Primary Healthcare Centre, with random assignment to two parallel groups and with evaluation and analysis by independent evaluators. A random assignment was made from 123 patients of the 149 initially recruited. ⋯ By ITT analysis, the change in the pain-VAS variable was greater among the experimental group (28.1 (95% CI 21.4-34.7)). The improvements in quality of life (physical aspect), active neck mobility and reduced rescue medication were clinically and statistically significant. In the treatment of the intensity of chronic neck pain, acupuncture is more effective than the placebo treatment and presents a safety profile making it suitable for routine use in clinical practice.