The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial Clinical Trial
A randomized study of the effect of oral lamotrigine and hydromorphone on pain and hyperalgesia following heat/capsaicin sensitization.
In this randomized double-blind placebo-controlled study, the analgesic effect of oral lamotrigine (400 mg) on cutaneous sensitization induced with the heat/capsaicin sensitization model was compared with the effect of oral hydromorphone (8 mg) in healthy volunteers. In a separate session, intravenous remifentanil (0.10 microg.kg(-1).min(-1)) and placebo were administered. This session was used as an additional reference comparator. ⋯ Compared with placebo, both intravenous remifentanil and oral hydromorphone significantly suppressed secondary hyperalgesia and acute thermal nociception. Oral lamotrigine did not reduce secondary hyperalgesia or acute thermal nociception but produced side effects of severity comparable with that of oral hydromorphone. Although lamotrigine is efficacious in the management of some types of chronic neuropathic pain, the lack of effect of this agent on human experimental pain suggests that its analgesic effects depend on nerve injury-associated abnormalities, which cannot be simulated in healthy human volunteers.
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Randomized Controlled Trial Clinical Trial
Interpretation of visual analog scale ratings and change scores: a reanalysis of two clinical trials of postoperative pain.
The visual analog scale (VAS) is one of the most commonly used measures of pain intensity in pain research. However, there remain important unanswered questions concerning interpretation of specific VAS ratings and change scores. ⋯ As predicted, in assessment of the amount of change corresponding to differing levels of pain relief, percentage change in a patient's VAS score was less biased by pretreatment pain than was absolute change score. The findings also suggested that a 33% decrease in pain represents a reasonable standard for determining that a change in pain is meaningful from the patient's perspective.