Articles: hyperalgesia.
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Randomized Controlled Trial Clinical Trial
Patients initially diagnosed as 'warm' or 'cold' CRPS 1 show differences in central sensory processing some eight years after diagnosis: a quantitative sensory testing study.
We used quantitative sensory testing (QST) to gain further insight into mechanisms underlying pain in CRPS 1. Specific goals were: (1) to identify altered patterns of sensory processing some 8 years after diagnosis, (2) to document differences in sensory processing between 'warm' and 'cold' diagnostic subgroups, (3) to determine relationships between changed sensory processing and disease progression regarding pain. The study was performed on a cohort of patients (n=47) clinically diagnosed with CRPS 1 of one upper extremity approximately 8 years previously. ⋯ The latter is not the case for warm CRPS 1 patients. Both diagnostic subgroups show greater pressure hyperalgesia on the affected limb and with disease progression. QST may prove useful in the subdiagnosis of CRPS 1 and in quantifying its progression, with both applications warranting further investigation for clinical and research use.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intravenous dextromethorphan to human volunteers: relationship between pharmacokinetics and anti-hyperalgesic effect.
The aim of this study was to investigate the effect of dextromethorphan (DM) 0.5 mg/kg administered intravenously (i.v.) on hyperalgesia and pain after a tissue injury in human volunteers, and to describe the relationship between pharmacokinetic and pharmacodynamic data. The heat-capsaicin sensitisation model, a well-established experimental hyperalgesia model was induced in 24 healthy, male volunteers aged 21-35 years. The subjects received i.v. ⋯ The pharmacokinetic-pharmacodynamic relationship showed a large inter-subject variation with a mean delay in effect of nearly 2 h in relation to peak serum concentration. The results strongly indicate that DM is an anti-hyperalgesic drug. The delay in effect may be explained by several mechanisms and suggests that timing of DM administration is an essential factor for using the drug in clinical settings.
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Randomized Controlled Trial Comparative Study Clinical Trial
Rofecoxib attenuates both primary and secondary inflammatory hyperalgesia: a randomized, double blinded, placebo controlled crossover trial in the UV-B pain model.
The analysis of drug's influence on peripheral and central sensitisation can give useful information about its mode of action and can lead to more efficacy in the treatment of pain. Peripheral inflammation is associated with peripheral expression and up-regulation of cyclooxygenase 2 (COX-2) in the CNS. The relative contribution of COX-2 mediated central sensitisation may be prominent under inflammatory conditions. ⋯ No significant difference between the three dosage groups was observed. These data confirm peripheral effects of rofecoxib in a human inflammatory UV-B pain model and provide circumstantial evidence that even a standard clinical dose of rofecoxib reduces central hyperalgesia in inflammatory pain. We confirm that the effect of single oral dose of rofecoxib plateaus at 50 mg.
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Randomized Controlled Trial Comparative Study Clinical Trial
Psychophysical outcomes from a randomized pilot study of manual, electro, and sham acupuncture treatment on experimentally induced thermal pain.
In this pilot study comparing the analgesic effects of three acupuncture modes--manual, electro, and placebo (with Streitberger placebo needles)--in a cohort of healthy subjects, we found that verum acupuncture treatment, but not placebo, lowered pain ratings in response to calibrated noxious thermal stimuli. This finding was mainly the result of highly significant analgesia in 5 of the 11 subjects who completed the 5-session study. Of the 5 responders, 2 responded only to electroacupuncture and 3 only to manual acupuncture, suggesting that acupuncture's analgesic effects on experimental pain may be dependent on both subject and mode. We developed a simple quantitative assessment tool, the Subjective Acupuncture Sensation Scale (SASS), comprised of 9 descriptors and an anxiety measure to study the relationship between the deqi sensation induced by acupuncture and the putative therapeutic effects of acupuncture. The SASS results confirm that the deqi sensation is complex, with all subjects rating multiple descriptors during each mode. We found significant correlations of analgesia with SASS ratings of numbness and soreness, but not with ratings of stabbing, throbbing, tingling, burning, heaviness, fullness, or aching. This suggests that attributes of the deqi sensation may be useful clinical indicators of effective treatment. ⋯ The results of this study indicate the existence of both individual subject and acupuncture mode variability in the analgesic effects of acupuncture. This suggests that switching acupuncture mode may be a treatment option for unresponsive patients.
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Randomized Controlled Trial Clinical Trial
Sumatriptan (5-HT1B/1D-agonist) causes a transient allodynia.
Unpleasant sensory symptoms are commonly reported in association with the use of 5-HT1B/1D-agonists, i.e. triptans. In particular, pain/pressure symptoms from the chest and neck have restricted the use of triptans in the acute treatment of migraine. The cause of these triptan induced side-effects is still unidentified. ⋯ There were no changes in ratings of brush intensity, tactile directional sensibility or cold or warm sensation thresholds. Thus, sumatriptan may cause a short-lasting allodynia in response to light dynamic touch and a reduction of heat and cold pain thresholds. This could explain at least some of the temporary sensory side-effects of triptans and warrants consideration in the interpretation of studies on migraine-induced allodynia.