Brazilian Journal of Anesthesiology
Brazilian Journal of Anesthesiology
Systematic Review

The effects of magnesium sulfate added to epidurally administered local anesthetic on postoperative pain: a systematic review

Os efeitos do sulfato de magnésio adicionado ao anestésico local administrado por via peridural na dor pós-operatória: uma revisão sistemática

Getúlio Rodrigues de Oliveira Filho, Adilto Mezzari Junior, Giulia Nonticuri Bianchi

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This study evaluated the efficacy of epidurally administered magnesium associated with local anesthetics on postoperative pain control.


The study protocol was registered in PROSPERO as CRD42021231910. Literature searches were conducted on Medline, Cochrane, EMBASE, CENTRAL, and Web of Science for randomized controlled trials comparing epidural administration of magnesium added to local anesthetics for postoperative pain in elective surgical adult patients. Primary outcomes were the time to the first Postoperative (PO) Analgesic Request (TFAR), 24-hour postoperative opioid consumption, and Visual Analog Scale (VAS) scores at the first six and 24 postoperative hours. Secondary outcomes included Postoperative Nausea and Vomiting (PONV), pruritus, and shivering. Quality of evidence was assessed using GRADE criteria.


Seventeen studies comparing epidural were included. Effect estimates are described as weighted Mean Differences (MD) and 95% Confidence Intervals (95% CI) for the main outcomes: TFAR (MD = 72.4 min; 95% CI = 10.22–134.58 min; p < 0.001; I2 = 99.8%; GRADE: very low); opioid consumption (MD = -7.2 mg (95% CI = -9.30 – -5.09; p < 0.001; I2 = 98%; GRADE: very low). VAS pain scores within the first six PO hours (VAS) (MD = -1.01 cm; 95% CI = -1.40–0.64 cm; p < 0.001; I2 = 88%; GRADE: very low), at 24 hours (MD = -0.56 cm; 95% CI = -1.14–0.01 cm; p = 0.05; I2 = 97%; GRADE: very low).


Magnesium sulfate delayed TFAR and decreased 24-hour opioid consumption and early postoperative pain intensity. However, imprecision and inconsistency pervaded meta-analyses, causing very low certainty of effect estimates.


Analgesia, epidural; Magnesium sulfate, therapeutic use; Pain, postoperative



Este estudo avaliou a eficácia do magnésio administrado por via peridural associado a anestésicos locais no controle da dor pós-operatória.


O protocolo do estudo foi registrado no PROSPERO como CRD42021231910. Pesquisas bibliográficas foram realizadas no Medline, Cochrane, EMBASE, CENTRAL e Web of Science para ensaios clínicos randomizados comparando a administração epidural de magnésio adicionado a anestésicos locais para dor pós-operatória em pacientes cirúrgicos eletivos adultos. Os desfechos primários foram o Tempo para a Primeira Solicitação de Analgésico Pós-operatório (PO) (TFAR), o consumo de opioides no pós-operatório de 24 horas e os escores da Escala Visual Analógica (VAS) nas primeiras seis e 24 horas de pós-operatório. Os desfechos secundários incluíram Náusea e Vômito Pós-operatório (NVPO), prurido e tremores. A qualidade da evidência foi avaliada usando critérios GRADE.


Dezessete estudos comparando peridural foram incluídos. As estimativas de efeito são descritas como diferenças médias ponderadas (MD) e intervalos de confiança de 95% (95% CI) para os principais resultados: TFAR (MD = 72,4 min; 95% CI = 10,22–134,58 min; p < 0,001; I2 = 99,8% ; GRAU: muito baixo); consumo de opioides (MD = -7,2 mg (95% CI = -9,30 - -5,09; p < 0,001; I2 = 98%; GRAU: muito baixo). Escores de dor VAS nas primeiras seis horas de PO (VAS) (MD = - 1,01 cm; IC 95% = -1,40–0,64 cm; p < 0,001; I2 = 88%; GRAU: muito baixo), em 24 horas (MD = -0,56 cm; IC 95% = -1,14–0,01 cm; p = 0,05; I2 = 97%; GRADE: muito baixo).


O sulfato de magnésio atrasou o TFAR e diminuiu o consumo de opioides em 24 horas e a intensidade da dor pós-operatória precoce. No entanto, a imprecisão e a inconsistência permearam as meta-análises, causando uma certeza muito baixa das estimativas de efeito.


Analgesia peridural; Uso terapêutico do sulfato de magnésio; Dor pós-operatória


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