Magnesium Hydroxide as a Complementary Aluminium-free Phosphate Binder to Moderate Doses of Oral Calcium in Uraemic Patients on Chronic Haemodialysis: Lack of Deleterious Effect on Bone Mineralisation

Abstract

To control hyperphosphataemia without hyperaluminaemia, A1(OH)3, which was given in addition to high doses of oral calcium, was replaced by Mg(OH)2 for 6 months in 20 haemodialysed patients and for 20 months in 12. The treatment during the control period was 110 +/- 91 mmol/day of oral calcium element given as CaCO3 and/or Calcium Sorbisterit and 1.05 +/- 1.47 g/day of A1(OH)3. Haemodialysis treatment was 4 h, thrice weekly. To prevent hypermagnesaemia, dialysate magnesium was decreased from 0.75 mmol/l to 0.375 mmol/l. After a control period of 3 months, Mg(OH)2 was given at a mean dose of 2.6 +/- 2 g/day and oral calcium supplements were decreased to 76 mmol/day. Two subsequent bone histomorphometry studies were performed at 8 month intervals in four patients and at 20 month intervals in seven patients. The results show a good control of plasma calcium (mean +/- SD: 2.43 +/- 0.1 mumol/l); phosphate (1.76 +/- 0.4 to 1.66 +/- 0.3 mmol/l); aluminum (1.3 +/- 0.1 mumol/l to 0.6 +/- 0.1 mumol/l); alkaline phosphatase (135 +/- 65 to 125 +/- 40 IU); and PTH fragments (PTH C terminal decreased from 260 +/- 214 to 185 +/- 182 pg/ml, PTH medium from 4185 +/- 5113 to 2270 +/- 4880 pg/ml). Plasma magnesium increased from 0.96 +/- 0.2 to 1.54 +/- 0.2 mmol/l. Bone histomorphometry shows no change in mineralisation, and a borderline decrease of resorption parameters. The main side-effects are (1) diarrhoea, which was well controlled by transient treatment with karaya gum, and (2) an increased need for potassium binders.(ABSTRACT TRUNCATED AT 250 WORDS)

Iron-Magnesium Hydroxycarbonate (Fermagate)

“…Hypermagnesemia is common in patients on hemodialysis (19) and sustained hypermagnesemia in a high proportion of peritoneal dialysis patients has also been described (20). Hypermagnesemia at levels up to 1.5 mmol/L is only rarely associated with clinical effects that are usually mild in severity (21)(22)(23)(24)(25)(26). Neuromuscular toxicity, although not evident in this study, may become apparent at levels of 2 to 3 mmol/L (27).…”

Ferric Citrate Controls Phosphorus and Delivers Iron in Patients on Dialysis

“…Also, ferric citrate had a lower average pill burden compared with sevelamer carbonate, with comparable phosphorus control. The few currently available phosphate binders have limitations, including aluminum toxicity, 12 diarrhea, [13][14][15][16][17] hypercalcemia, 14 and patient tolerability issues. [14][15][16][17][18] There were more discontinuations for all causes, including renal transplantation, in the ferric citrate versus active control groups (33% ferric citrate versus 23% active control).…”

“…The few currently available phosphate binders have limitations, including aluminum toxicity, 12 diarrhea, [13][14][15][16][17] hypercalcemia, 14 and patient tolerability issues. [14][15][16][17][18] There were more discontinuations for all causes, including renal transplantation, in the ferric citrate versus active control groups (33% ferric citrate versus 23% active control). This result was largely because of more GI non-serious AEs, such as diarrhea and bloating, early in the study in subjects receiving ferric citrate (Supplemental Appendix).…”

Control of Hyperphosphatemia among Patients with ESRD

“…However, these agents are not particularly effective as phosphate binders, and adjustments in dialysate magnesium are necessary (42). Given the lower efficacy of phosphorus binding of magnesium salts, larger doses are required and adverse GI effects such as diarrhea, hyperkalemia, and hypermagnesemia are often treatment limiting (43)(44)(45). MagneBind (Nephro-Tech Inc., Shawnee, KS) is a commercially available binding agent that contains varying amounts of magnesium carbonate and calcium carbonate.…”