Efeitos da clonidina por via muscular e perineural no bloqueio do nervo isquiático com ropivacaína a 0,5%

Helayel, Pablo Escovedo; Kroth, Luciano Manoel Martins; Boos, Gustavo Luchi; M, Jahns; Filho, Getúlio Rodrigues de Oliveira

doi:10.1590/s0034-70942005000500002

Cited by 9 publications

(9 citation statements)

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“…Both the perineurally- and the systemically administered clonidine would be absorbed, and exert systemic effects. The contradicting results observed in these trials [ 6 , 26 – 29 ] could be explained by the pharmacokinetic profile of clonidine. Perineural administered clonidine may have a different rate of absorption, compared to the subcutaneous or intramuscular administered clonidine and could explain the difference in duration of nerve blocks reported between perineural and systemic groups in these studies.…”

Section: Discussionmentioning

confidence: 87%

“…All patients received active nerve blocks with local anesthetic and either perineural-, systemic- or no clonidine (placebo). Again, results are conflicting [ 6 , 26 – 29 ].…”

Section: Discussionmentioning

confidence: 99%

“…Helayel et al [ 6 ] used intramuscular clonidine as a systemic adjuvant to ropivacaine in a sciatic nerve block for foot and ankle surgery, whereas Culebras et al [ 26 ] added a group receiving intramuscular clonidine as an adjuvant to bupivacaine in an interscalene block for rotator cuff repair. Both trials found no difference in duration of analgesia between the perineural, systemic and placebo groups, suggesting that there is no effect of clonidine used as an adjuvant.…”

Section: Discussionmentioning

confidence: 99%

“…The only clinical study including a systemic control group, added clonidine to ropivacaine in a sciatic-femoral nerve block. This study showed no difference in block duration between the placebo, systemic or perineural groups [ 6 ] suggesting no clinically relevant effect of clonidine.…”

Section: Introductionmentioning

confidence: 94%

“…The efficacy of clonidine used as an adjuvant to ropivacaine remains controversial. Some trials report a prolongation in the duration of nerve block [ 1 – 3 ], whereas others do not [ 4 – 6 ]. In-vitro animal studies have demonstrated a perineural effect of block prolongation, mediated through a direct inhibition of the I h current in C-fibers [ 7 ], but clonidine also possess systemic analgesic properties.…”

Section: Introductionmentioning

confidence: 99%

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Clonidine used as a perineural adjuvant to ropivacaine, does not prolong the duration of sensory block when controlling for systemic effects: A paired, blinded, randomized trial in healthy volunteers

et al. 2017

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BackgroundClonidine used as an adjuvant to ropivacaine have been shown to prolong the duration of peripheral nerve blocks. The mechanism of action remains unclear. We hypothesized, that clonidine used as an adjuvant to ropivacaine extends the duration of an adductor canal block (ACB) by a peripheral mechanism, compared to ropivacaine alone when controlling for systemic effects.MethodsWe conducted a paired, blinded, randomized trial in healthy volunteers. Participants received bilateral ACBs containing 20 ml ropivacaine 0.5% + 1 ml clonidine 150μg/ml in one leg and 20 ml ropivacaine 0.5% + 1 ml saline in the other leg. The primary outcome measure was duration of sensory block assessed by temperature sensation (alcohol swab). Secondary outcome measures were duration of sensory block assessed by: pinprick, maximum pain during tonic heat stimulation, warmth detection threshold and heat pain detection threshold.ResultsWe enrolled 21 volunteers and all completed the trial. There was no difference in duration of sensory block assessed with an alcohol swab: Mean duration in the leg receiving ropivacaine + clonidine was 19.4h (SD 2.7) compared to 19.3h (SD 2.4) in the leg receiving ropivacaine + placebo with a mean difference of 0.1h (95% CI: -1.0 to 1.3), P = 0.83. No differences in block duration were detected when assessed by: Pinprick, mean difference 0.0 h (95% CI: -1.3 to 1.3), maximum pain during tonic heat stimulation, mean difference -0.7 h (95% CI: -2.1 to 0.8), warmth detection threshold, mean difference -0.1 h (95% CI: -1.8 to 1.6) or heat pain detection threshold, mean difference -0.2 h (95% CI: -1.7 to 1.4).ConclusionsAdministering clonidine perineurally as an adjuvant to ropivacaine in an ACB did not prolong the duration of sensory block in a setup controlling for systemic effects of clonidine.

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Section: Discussionmentioning

confidence: 87%

“…All patients received active nerve blocks with local anesthetic and either perineural-, systemic- or no clonidine (placebo). Again, results are conflicting [ 6 , 26 – 29 ].…”

Section: Discussionmentioning

confidence: 99%