Proton Pump Inhibitor Induced Hypomagnesemia Causing Seizures: A Rare Adverse Effect of a Commonly Used Medication.

Hypomagnesemia is defined as serum magnesium levels less than 0.7mmol/L and can result in a plethora of symptoms ranging from mild gastrointestinal symptoms to serious conditions such as cardiac arrhythmias and neurological complications. When considering the etiological factors, drug-induced hypomagnesemia is highlighted because commonly used medications such as proton pump inhibitors (PPIs), aminoglycoside antibiotics, and loop and thiazide diuretics can cause low magnesium levels. A 49-year-old male presented to the emergency department with severe vomiting worsening over three days complicated with generalized tonic-clonic seizures. He was an averagely built male, a non-smoker, and a non-alcoholic with no significant co-morbidities. He had a history of chronic over-the-counter pantoprazole intake over the last one year, and apart from that, his medication history was unremarkable. Initial investigations revealed severe hypomagnesemia (with serum magnesium level of 0.1mmol/L), with marginal hypokalemia, hypophosphatemia, and hypocalcemia. Following the initial resuscitation and magnesium supplementation, the patient's clinical condition significantly improved. Due to the lack of proper knowledge, the patient continued to take omeprazole 20mg tablets after discharge, and up until proper education and total cessation of PPIs, marginal hypomagnesemia, with serum magnesium level of 0.5mmol/L, persisted without any significant overt clinical manifestations. In this case report, we intend to highlight the importance of assessing for all possible electrolyte abnormalities in a patient presenting with neurological symptoms, relevance of taking a thorough drug history including all undocumented over-the-counter medications, and importance of patient education in the prevention of further episodes.