An old friend turned foe: Metformin-induced diarrhea with resultant symptomatic hypokalemia, hypomagnesemia, hypocalcemia, and hypophosphatemia

Metformin is known for gastrointestinal side effects, but has rarely been associated with diarrhea severe enough to cause symptomatic electrolyte abnormalities and hospitalization. This case illustrates such that occurred despite multiple outpatient encounters for diarrhea. Additionally, this case highlights the importance of a comprehensive medical reconciliation as part of a thorough medical evaluation.