Articles: nerve-block.
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Comparative Study
Site 1 sodium channel blockers prolong the duration of sciatic nerve blockade from tricyclic antidepressants.
Many recent reports in the literature address the local anesthetics efficacy of tricyclic antidepressants (TCAs). Here we investigated whether nerve block from TCAs is prolonged by site 1 sodium channel blockers such as tetrodotoxin and saxitoxin, which are known to prolong block from conventional local anesthetics. Tetrodotoxin and saxitoxin greatly prolonged block from TCAs. ⋯ Systemic (subcutaneous) delivery of tetrodotoxin or amitriptyline did not result in prolongation of block from the other class of drug injected at the sciatic nerve. In TCA-containing formulations, motor blockade was consistently longer than thermal nociceptive block; motor blockade was also prolonged by tetrodotoxin and saxitoxin. In summary site 1 sodium channel blockers prolong the duration of TCAs via a locally mediated mechanism.
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Anesthesia and analgesia · Jul 2004
Preoperative sciatic nerve block decreases mechanical allodynia more in young rats: is preemptive analgesia developmentally modulated?
Postoperative sensitivity to tactile stimuli differs as a function of age. In this study, we hypothesized that preoperative sciatic nerve block (SNB), by providing preemptive analgesia, would result in better analgesia than postoperative SNB in the young rat. With the paw incision model of postoperative pain, male Sprague-Dawley rats, aged 2 or 4 wk, underwent general anesthesia and then received a left SNB with 5 microL/g of 0.5% bupivacaine or normal saline. ⋯ At 24 h, the threshold was 4.0 +/- 0.7 g in the preoperative SNB group compared with 1.6 +/- 0.3 g in the postoperative SNB group (P = 0.004). There was no difference at any time point between the preoperative and the postoperative SNB in the 4-wk-old animals. These results suggest that preoperative SNB in young animals provides a preemptive analgesic effect on mechanical allodynia that is age or developmentally dependent.