RESUMEN
BACKGROUND: Hypokalemia is a common disorder that can negatively affect organ function. Magnesium supplementation is frequently recommended despite limited evidence to support its use. OBJECTIVES: The purpose of this study was to evaluate the clinical effects of magnesium coadministration in patients treated for hypokalemia in the emergency department (ED). METHODS: This retrospective, single-center study evaluated adults treated with intravenous (i.v.) potassium for hypokalemia (serum potassium <3.5 mMol/L) in the ED between July 1, 2016 and June 30, 2020. Patients given magnesium supplementation within 4 h of potassium administration (MG+) were compared with those not given concurrent magnesium (MG-). The primary outcome was time to potassium normalization (≥ 3.5 mMol/L). Secondary outcomes included clinical effects, adverse effects, and dosing of magnesium and potassium. RESULTS: Two hundred patients were included (MG+ = 100; MG- = 100). Patients in the MG- group more frequently had history of myocardial infarction (16% vs. 6%; p = 0.02) and alcoholism (16% vs. 6%; p = 0.02). Patients in the MG+ group had higher incidence of symptomatic hypokalemia (34% vs. 19%; p = 0.02) and severe hypokalemia (serum potassium < 2.5 mMol/L) (15% vs. 8%; p = 0.03). There were no differences in time to serum potassium normalization, change in serum potassium after treatment, or incidence of potassium normalization within 24 h of treatment. MG+ patients required more potassium within 24 h of treatment and more frequently developed hypermagnesemia (serum magnesium >1.1 mMol/L). CONCLUSIONS: Magnesium coadministration during hypokalemia treatment did not affect time to serum potassium normalization but was associated with more hypermagnesemia.