Effect of Proton Pump Inhibitors with Diuretics on Magnesium Levels: Is It Real and Clinically Relevant?

Abstract

Introduction: Proton pump inhibitors (PPIs) are among the most commonly prescribed medications in the US. Reports of hypomagnesemia in association with PPI use have surfaced in the past several years. Due to scant literature, veracity and clinical relevance of these findings remains to be determined. There has also been concern regarding the concomitant use of varying doses of PPIs and diuretics, as the latter are known to affect magnesium (Mg) levels. Our purpose was to examine Mg levels in patients on PPIs and/or diuretics of different potencies, and to assess for associated clinical relevance.Figure 1Figure 2Methods: This was a retrospective chart review study of 3200 randomly selected adult medical inpatients, 39 years or older, admitted to Charleston Area Medical Center from January 1999 to August 2014. Patients were divided into 8 groups (N=400 each) based on PPI and diuretic doses at time of admission: a) not taking PPIs or diuretics, b) those taking PPIs alone, c) those taking diuretics alone (high and low dose thiazide, high dose loop diuretics), d) and those taking PPIs with high and low dose thiazide, or high dose loop diuretics. Mg levels and clinical data were compared within the groups. Electrocardiograms were also reviewed in patients with very low Mg levels (< 1.0 mg/dL). Results: Of 3200 patients studied, there was no statistically significant difference in the mean Mg levels between the groups. When groups with Mg <1.2 mg/dL were compared, there was a trend towards low Mg levels in study groups on PPIs compared to those not on PPIs but it was not statistically significant. High versus low doses of PPIs also did not alter Mg levels in the study group on high dose diuretics. In addition, QTc intervals in the group with very low magnesium levels (<1.0 mg/ dL) was not statistically different compared to those with normal Mg levels.Figure 3Conclusion: We observed that PPIs alone or in combination with diuretics at varying potencies were not associated with significant hypomagnesemia. Marked hypomagnesemia (≤ 1.0 mg/dL) was not associated with significant QTc prolongation. This study provides reassurance that checking magnesium levels may not be necessary in patients on PPIs alone or with diuretics.