Magnesium Sulfate as an Analgesic and Sedative-sparing Agent in Patients under Mechanical Ventilation: A Randomized, Double Blind Clinical Trial.

OBJECTIVES: The efficacy of intravenous magnesium sulfate in reducing sedative and analgesic requirements was examined in patients under mechanical ventilation. METHODS: In this randomized clinical trial, patients requiring mechanical ventilation received either magnesium sulfate (serum magnesium target level: near 3 mg/dL) or placebo concurrently with the hospital analgosedation protocol. The calculated dose of magnesium in the intervention group was infused over 24 h. The primary outcome of the study was the cumulative opioid requirement at 24 and 48 h after intubation. FINDINGS: A total of 110 patients were randomly assigned to either the placebo (n = 54) or the magnesium sulfate (n = 56) group. The results showed that the cumulative opioid consumption in the magnesium group was significantly less than in the control group at 24 h postintervention (120 mg vs. 214 mg, P < 0.001). This difference remained significant at 48 h postintervention (240 mg vs. 433 mg, P < 0.001). In addition, in the adjusted analysis using analysis of covariance, after adjustment for the model for acetaminophen dose and additive sedatives as confounders, this still remained statistically significant (P < 0.001). CONCLUSION: Administration of magnesium sulfate targeting a serum magnesium level near 3 mg/dL in patients under mechanical ventilation reduced opioid requirements and may be considered as an analgesic and sedative-sparing agent.