Hypomagnesemia With Metformin Use in Diabetes Mellitus: A Case and Narrative Review

Hypomagnesemia is defined as a serum magnesium level <1.7 mg/dL, and it can be induced by gastrointestinal losses or renal wasting of magnesium. This is a common electrolyte abnormality in patients with diabetes mellitus. Refractory hypomagnesemia presents a significant challenge in clinical management, because some patients are prone to developing severe, recurrent hypomagnesemia that is refractory to aggressive repletion. In diabetes, insulin resistance in renal tissue inhibits magnesium reabsorption and contributes to the hypomagnesemia observed in these patients. Hypomagnesemia has also been reported with use of metformin and may be because of gastrointestinal wasting and intracellular accumulation. Chronic use of metformin suppresses transient receptor potential cation channel subfamily M member 6 in the kidneys, although it also appears to reduce urinary magnesium excretion. In addition to repletion aadnd using potassium-sparing diuretics, substituting sodium-glucose cotransporter 2 inhibitors for metformin may be helpful in managing refractory hypomagnesemia in patients with diabetes.