• Fabricio T Mendonça, Douglas Pellizzaro, Breno J Grossi, Luise A Calvano, Luiz S F de Carvalho, and Andrei C Sposito.
• From the Department of Anaesthesiology, Hospital de Base do Distrito Federal, Brasilia, Federal District (FTM, DP, BJG, LAC) and Cardiology Department, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil (LSFC, ACS).
• Eur J Anaesthesiol. 2020 Mar 1; 37 (3): 224-234.

BackgroundRecently, the use of venous adjuvants, such as lidocaine and magnesium sulfate, has been gaining ground in multimodal analgesia. However, no study has evaluated the impact a combination of the two drugs.ObjectivesTo evaluate the efficacy of venous adjuvants in reducing opioid consumption and pain scores after mastectomy.DesignRandomised, double-blind, parallel-group, noninferiority clinical trial with a 1 : 1 : 1 : 1 allocation ratio.SettingHospital de Base do Distrito Federal, Brasilia, Federal District, Brazil from November 2014 to December 2017.PatientsOne-hundred and ninety-eight patients were electively scheduled for mastectomy. Seventy-eight were excluded.InterventionsIntra-operative infusions of remifentanil (0.1 μg kg min), lidocaine (3 mg kg h), magnesium sulfate (50 mg kg + 15 mg kg h) or lidocaine with magnesium sulfate were used. All patients received standard general anaesthesia.Main Outcome MeasuresPeri-operative opioid consumption and pain scores.ResultsThe patients who received both lidocaine and magnesium sulfate group (n=30) consumed less alfentanil during surgery (P < 0.001) and less dipyrone (P < 0.001) and morphine (P < 0.001) in the postoperative period. Only two patients (6.7%) in the lidocaine and magnesium sulfate group needed morphine (P < 0.001). These requirements were significantly lower when compared with patients who received remifentanil (n=30; 76.6%) and magnesium sulfate (n=30; 70%; odds ratio 46.0, 95% confidence interval 8.69 to 243.25, P < 0.001, and odds ratio 32.66, 95% confidence interval 6.37 to 167.27, P < 0.001, respectively). The patients of the lidocaine and magnesium sulfate group had lower pain scores in the first 24 h postoperatively using the numerical rating scale and verbal rating scale at discharge from the postanaesthesia care unit (P < 0.001), after 12 h (P < 0.001) and after 24 h (P < 0.001) when compared with the other three groups.ConclusionOur findings suggest a synergistic effect of the use of both lidocaine and magnesium in peri-operative pain. This may be another potential strategy in the multimodal analgesia regimen.Trial RegistrationClinicalTrials.gov Identifier: NCT02309879.

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