Severe hypermagnesemia induced by magnesium oxide ingestion: a case series

Abstract

Hypermagnesemia is generally considered an exceptional iatrogenic condition usually caused by magnesium-containing cathartics. In particular, this condition often develops when magnesium-containing cathartics are administered to elderly patients with renal insufficiency or bowel movement dysfunction. Although magnesium oxide (MgO) is widely prescribed as a laxative, serum magnesium concentration has not been examined in most cases. In this report, we present the cases of four elderly patients with constipation and symptomatic hypermagnesemia caused by MgO ingestion, one of which had a lethal course. All of the patients were older than 65 years and with renal dysfunction. In addition, they had difficulties in expressing their symptoms because of cerebrovascular events or dementia. These cases suggest that hypermagnesemia caused by magnesium-containing cathartics is more likely to develop than previously recognized and that physicians should be aware that patients with chronic kidney disease and the elderly are at risk of hypermagnesemia on magnesium administration. We recommend serum magnesium monitoring for high-risk patients after initial prescription or dose increase.

Clinical features of hypermagnesemia in patients with functional constipation taking daily magnesium oxide

“…High CKD, greater age, and long-term use of magnesium oxide were shown to be risk factors for hypermagnesemia. (3,(5)(6)(7)(8)(9)(10) Most of these studies, however, were case reports or studies of certain groups, including elderly patients, children, and patients undergoing hemodialysis. The results of the present retrospective cohort study showed that reduced renal function was the most important risk factor for hypermagnesemia and high serum magnesium concentration in patients taking magnesium oxide for functional constipation.…”

“…(3) Prolonged treatment with magnesium oxide, however, may induce hypermagnesemia. (4)(5)(6)(7)(8)(9) Serum magnesium concentrations >5.0 mg/dl have been associated with nausea, headache, light-headedness, and cutaneous flushing, whereas levels above 12 mg/dl have been associated with respiratory failure, complete heart blockage, and cardiac arrest. (10) Recently, the Japanese Ministry of Health, Labour and Welfare recommended that serum magnesium concentrations be measured periodically in geriatric patients and in patients administered magnesium oxide for prolonged periods of time (http://www.pmda.…”

Severe Hypermagnesemia with Normal Renal Function Can Improve with Symptomatic Treatment

“…Many reports have described the treatment of hypermagnesemia with hemodialysis [1-3, 5-7, 9, 12, 13]. However, few reports have described hypermagnesemia in patients with normal renal function [1,5,[7][8][9], and even fewer reports have described severe hypermagnesemia that improved with symptomatic treatment alone [7]. In our case, serum Mg levels in the patient normalized without hemodialysis.…”

“…Intravenous infusion of normal saline and loop diuretics enhances Mg excretion in patients with normal renal function [3]. In particular, loop diuretics inhibits Mg reabsorption in the thick ascending limb of Henle's loop [8]. Hemodialysis is necessary for patients with renal failure and life-threatening symptoms [3,6].…”

“…Notably, severe hypermagnesemia with renal failure and life-threatening symptoms usually requires hemodialysis [3,6]. However, few reports have described hypermagnesemia in patients with normal renal function [1,5,[7][8][9], and even fewer reports have described severe hypermagnesemia that improved with symptomatic treatment alone [7]. We report a severe hypermagnesemia patient with normal renal function, who was treated without hemodialysis.…”