Magnesium and Alcohol Withdrawal Syndrome

Summary

A Cochrane review [Abstract] 1 included 4 studies with a total of 317 subjects. Three trials studied oral magnesium, with doses ranging from 12.5 mmol/day to 20 mmol/day. One trial studied parenteral magnesium (16.24 mEq q6h for 24 hours). Only one trial measured clinical symptoms of seizure, delirium tremens or components of the Clinical Institute Withdrawal Assessment for Alcohol (CIWA) score. A single outcome (handgrip strength) in three trials (113 people), was amenable to meta-analysis. There was no significant increase in handgrip strength in the magnesium group (SMD 0.04; 95% CI -0.22 to 0.30). No clinically important changes in adverse events were reported.

A prospective observational study 2 in patients (n = 127) presenting to the emergency department with alcohol withdrawal syndrome (AWS) assessed their thiamine and magnesium status. The majority of patients (99%) had whole blood thiamine diphosphate concentration within/above the reference interval (275 to 675 ng/gHb) and had been prescribed thiamine (70%). In contrast, the majority of patients (60%) had low serum magnesium concentrations (< 0.75 mmol/L) and had not been prescribed magnesium (93%). The majority of patients (66%) had plasma lactate concentrations above 2.0 mmol/L. At 1 year, 13 patients with AWS had died giving a mortality rate of 11%. Male gender (p < 0.05), BMI< 20 kg/m2 (p < 0.01), Glasgow Modified Alcohol Withdrawal Score max ≥ 4 (p < 0.05), elevated plasma lactate (p < 0.01), low albumin (p < 0.05) and elevated serum CRP (p < 0.05) were associated with greater 1-year mortality. Also, low serum magnesium at time of recruitment to study and low serum magnesium at next admission were associated with higher 1-year mortality rates, (84% and 100% respectively; both p < 0.05).

A retrospective study 3 examined the relationship between serum magnesium concentrations and mortality in patients with AWS (n=700). Of 380 patients included in the sample analysis, 64 (17%) were dead at 1 year following the time of treatment for AWS. The majority of patients had been prescribed thiamine (77%) and a proton pump inhibitor (66%). In contrast, the majority of patients had low circulating magnesium concentrations (<0.75 mmol/L) (64%) and had not been prescribed magnesium (90%). The median age of death at one year was 55 years (P = 0.002). On multivariate binary logistic regression analysis, age > 50 years (OR 3.37, 95% CI 1.52 to 7.48, P < 0.01), AST:ALT ratio >2 (OR 3.10, 95% CI 1.38 to 6.94, P < 0.01) and magnesium < 0.75 mmol/L (OR 4.11, 95% CI 1.3 to 12.8, P < 0.05) remained independently associated with death at 1 year.