Iatrogenic hypomagnesemia: an underestimated clinical problem

Hypomagnesemia is defined by having a serum magnesium level of less than 1.7 mg/dL. The magnesium balance is tightly regulated by the concerted actions of the intestine, bone and kidneys. This balance can be disturbed by a wide variety of drugs. Recently, we observed a case of severe hypomagnesemia caused by proton pump inhibitor therapy. We conducted a retrospective study of an <em>intrahospital population</em> to evaluate the prevalence of hypomagnesemia and the relationship with associated drugs. Among 181 patients with hypomagnesemia only 29 were found to have hypomagnesemia with specific causes, such as chronic diarrhea, vomiting, and so on. In the remaining patients, 120 have taken proton pump inhibitors and/or diuretics and/or metformin. Clinicians should consider proton pump inhibitors as a possible causative agent when investigating hypomagnesemia and they should be especially attentive with patients who take proton pump inhibitors, especially in cases of long-term therapy (≥1 year) and/or concomitant administration of other agents that may lower magnesium levels (<em>e.g</em>., diuretics or metformin).