TITLE:
Changes in Serum Magnesium after Increasing Dialysate Magnesium in Hemodialysis Patients: A Prospective Case Series
AUTHORS:
Konstantinos S. Mavromatidis, Irini M. Kalogiannidou, Pelagia A. Kriki, Emine S. Impis, Gkiounai J. Katzel Achmet
KEYWORDS:
Serum Magnesium, Dialysate Magnesium, Hypomagnesemia, Online HDF, Conventional Hemodialysis
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.13 No.11,
October
31,
2025
ABSTRACT: Aim: Due to the observation of decreased serum magnesium levels in some patients of our hemodialysis unit, who also had clinical signs of hypomagnesemia, this prospective case series study was designed to investigate if the dialysate magnesium of 0.50 mg/L which we use was sufficient or not for the needs of these patients. This study aimed to evaluate how increasing magnesium dialysate from 0.50 to 0.75 mmol/L affects serum magnesium levels and related symptoms in hemodialysis patients. Patients-Methods: Serum magnesium levels were examined in all of our dialyzed patients, with a dialysate magnesium of 0.50 mmol/L, to assess whether these were normal serum magnesium levels and not responsible for clinical manifestations (of hypomagnesemia) that we had found in some of them. Serum magnesium levels were determined before a mid-week dialysis session (Wednesday or Thursday). Those who were below the lower normal limits would be given oral magnesium oxide, initially at a dose of 300 mg/24 hours, and if these were not restored, the drug would be administered at a double dose. If magnesium levels were restored with this dose, the dialysate magnesium would be changed from 0.50 to 0.75 mmol/L, with oral magnesium discontinued. Results: Initially, the mean serum magnesium level in the 60 patients was 0.91 ± 0.15 mmol/L (2.18 ± 0.36 mg/dl), with 15 of them having levels below 0.83 mmol/L, with a minimum value of 0.44 and a maximum of 1.29 mmol/L. There was no correlation between the serum magnesium levels and the dialysis method (0.90 ± 0.14 vs 0.90 ± 0.17 mmol/L, p=NS), and no correlation was noted from the presence of diabetes mellitus, hypoalbuminemia, or the existence of diuresis and the use of diuretics. The oral administration of magnesium oxide at a dose of 300 mgx2/24 hours was shown to restore serum magnesium levels, as was the increase in the dialysate magnesium from 0.50 to 0.75 mmol/L (after 4 months, the mean serum magnesium levels were 1.15 ± 0.17 and after another 4 months, were 1.10 ± 0.18 mmol/L). With these serum magnesium levels, no patients had the symptoms of hypomagnesemia that they had when the study began. A small percentage of patients who dialyzed with a dialysate magnesium of 0.75 mmol/L had serum magnesium levels above the normal range (15/60 patients after 4 months on dialysate magnesium 0.75 mmol/L and 9 after another 4 months with the same dialysate), without clinical manifestations of hypermagnesemia. Conclusions: It is concluded that the serum magnesium of many dialyzed patients is low when they are being dialyzed with a dialysate magnesium of 0.50 mmol/L, and the use of a dialysate magnesium of 0.75 mmol/L in all patients is, in our opinion, without risk of hypermagnesemia, ensuring many beneficial effects.