Severe Hypomagnesemia with Long-Term Use of a Proton Pump Inhibitor: A Case Report

Abstract

Hypomagnesemia is a rare, though likely under-recognized, adverse effect of long-term use of proton pump inhibitors (PPIs), one of the most commonly prescribed classes of medications in North America. Hypomagnesemia can cause potentially life-threatening neurologic abnormalities, cardiac arrhythmias, and secondary electrolyte disorders. In this manuscript we present the case of a long-term PPI user who presented with an episode of decreased level of consciousness. He was found to have severe hypomagnesemia with avid renal retention of magnesium, secondary hypocalcemia with an inappropriately normal parathyroid hormone level, and hypokalemia. His serum magnesium and other electrolyte abnormalities rapidly corrected with cessation of PPI use and electrolyte supplementation. Given the propensity for patients with hypomagnesemia associated with PPI use to go unrecognized until they present with severe symptomatic hypomagnesemia, we recommend that patients being started on a PPI for an intended long-term course have baseline testing of serum magnesium and monitoring of magnesium on an annual basis, or sooner, if they develop symptoms.