The authors of this brief report in the Archives of Internal Medicine note that severe magnesium deficiency associated with use of proton pump inhibitors (PPIs) has been described recently, with varying clinical presentations.  They describe an asymptomatic case of hypomagnesaemia associated with chronic PPI use for the treatment of gastroesophageal reflux disease (GORD) in a 67-year-old female patient.  Evaluation as part of a general pre-operative assessment showed an unexplained hypomagnesaemia with a very low urine magnesium excretion rate. After uncomplicated surgery for GORD she was able to discontinue her PPI therapy, after which her serum and urinary magnesium levels normalised.

The authors note that this is the first report, to their knowledge, of asymptomatic hypomagnesaemia related to PPI use, which they suggest may be an under-reported side-effect.  As mild hypomagnesaemia is associated with a higher risk of developing perioperative arrhythmia, they suggest that consideration be given to monitoring magnesium levels in patients taking PPIs, especially in a preoperative setting.