Another concern is the association between long-term PPI use and hypomagnesemia. In March 2011, the FDA issued an advisory warning that patients taking PPIs may be at risk for hypomagnesemia. There have been 30 cases of severe hypomagnesemia reported in long-term PPI users that normalized after the PPI was discontinued. Although the mechanism is not known, in some patients, PPIs appear to interfere with active transport of magnesium across the intestinal wall or cause excessive loss into the intestinal lumen.44 It is therefore recommended that before initiating patients into PPIs for long-term therapy (Q1 year) and when coadministered with diuretics or digoxin, serum magnesium levels should be obtained and monitored periodically.