Metabolic and clinical effects of oral magnesium supplementation in furosemide-treated patients with severe congestive heart failure

Background: Magnesium depletion and hypomagnesemia are common among furosemide-treated patients with chronic congestive heart failure. Hypothesis: This investigation evaluated clinical and metabolic effects of oral magnesium supplementation. Methods: Ten patients with severe congestive heart failure maintained on high dose furosemide (≥ 80 mg/day) received a supplement of oral magnesium citrate 300 mg/daily for 30 days. Clinical parameters were followed, and peripheral blood mononuclear cell magnesium and zinc content, serum and urine magnesium, potassium, zinc, calcium, phosphorus, and creatinine were assessed. Results: Peripheral blood mononuclear cell magnesium content and serum potassium rose significantly at the end of the study (2.09 ± 1.89 to 3.99 ± 2.26 μg/mg cell protein, p < 0.05, and 4.17 ± 0.38 to 4.39 ± 0.27 mEq/l, p < 0.05, respectively), while the other parameters remained unchanged. Conclusion: In some of these patients, oral magnesium supplementation is effective in achieving substantial increments in intracellular magnesium and serum potassium which, in turn, may have cardioprotective effects.