Pain
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Comparative Study
Clinically important difference thresholds of the visual analog scale: a conceptual model for identifying meaningful intraindividual changes for pain intensity.
The aim of this study was to estimate a range of clinically important difference (CID) values of the visual analog scale for pain intensity (VAS-PI), and to assess the effect of patient baseline characteristics on VAS change scores. Data from a prospective cohort study with 678 patients with subacute and chronic temporomandibular disorder pain were analyzed. Patients were divided into 9 cohorts on the basis of the baseline VAS score and the duration of pain. ⋯ For the VAS change scores, the main effect of the variable baseline pain level was significant (F=107.09, P<.001). However, there was no significant baseline pain level by duration of pain interaction effect (F=1.13, P=.340). On the basis of the results, we advocate the choice of a single CID value according to the context of the patient's baseline level of pain.
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Venoms peptides have produced exceptional sources for drug development to treat pain. In this study we examined the antinociceptive and side effects of Tx3-3, a peptide toxin isolated from Phoneutria nigriventer venom, which inhibits high-voltage-dependent calcium channels (VDCC), preferentially P/Q and R-type VDCC. We tested the effects of Tx3-3 in animal models of nociceptive (tail-flick test), neuropathic (partial sciatic nerve ligation and streptozotocin-induced diabetic neuropathy), and inflammatory (intraplantar complete Freund's adjuvant) pain. ⋯ On the other hand, i.t. injection of Tx3-3 did not alter inflammatory pain. Taken together, our data show that Tx3-3 shows prevalent antinociceptive effects in the neuropathic pain models and does not cause adverse motor effects at antinociceptive efficacious doses, suggesting that this peptide toxin holds promise as a novel therapeutic agent for the control of neuropathic pain. The Brazilian armed spider Tx3-3, a new P/Q and R-type calcium channel blocker, effectively alleviates allodynia in animal neuropathic pain models.