Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2017 Publisher: Fresenius Medical Care Nephrologica Deutschland GmbH, Else-Kröner-Straße 1, 61352 Bad Homburg v.d.H., Germany
Pharmacotherapeutic group: Drugs for treatment of hyperkalemia and hyperphosphatemia
ATC-Code: V03AE04
As calcium acetate and magnesium carbonate are phosphate-binding compounds, they lead together with the phosphate contained in food to the formation of low solubility calcium and magnesium phosphate-salts in the gut, which then will be excreted with the faeces. Calcium acetate reaches its maximal phosphate-binding capacity at a pH of 6–8. Therefore, OsvaRen is also suitable for phosphate binding in patients with hypo- or anacidity of the stomach.
Provided that no precipitation to magnesium complexes is caused by dietary phosphate or other nutrients, the dissolved magnesium ions are bioavailable and are absorbed in the intestine.
The absorption of orally administered magnesium in healthy humans depends on the supply. Experiments have shown that the rate of absorption in patients who received 1.5 mmol magnesium per day was 65%, and in patients who received 40 mmol per day it was only 11%.
The dissolved calcium ions are bioavailable and can be absorbed via the intestinal route as long as calcium does not form insoluble calcium complexes with the phosphate contained in food or other nutrients. Absorption of calcium is governed by hormonal regulatory mechanisms. The ratio of absorption increases with higher doses and with hypocalcaemic states and decreases with increasing age. Depending on the vitamin D status and the doses taken, a fractional absorption of 10-35% can be expected. Administration of higher doses will only result in a smaller increase of the amount absorbed. The normal daily intake with food amounts to approx. 1000 mg.
Total body magnesium is about 20–28 g. In healthy adults about 53% of total body magnesium is in bone, 27% in muscle, 19% in soft tissue and less than 1% extracellular. The majority of intracellular magnesium is found in bound form. Total body calcium is about 1250 g (31 mol) in a person weighting 70 kg, of which 99% is located in bones and teeth. About 1 g is in the plasma and the extracellular fluid, and 6 to 8 g in the tissues themselves. Reference values for serum total calcium vary among clinical laboratories, depending on the methods of measurement, within a normal range of 2.15-2.57 mmol/l. About 40 to 45% of this quantity is bound to plasma proteins, about 8 to 10% is complexed with ions such as citrate, and 45 to 50% is dissociated as free ions.
Orally administered magnesium salts are eliminated in the urine (absorbed fraction) and the faeces (unabsorbed fraction). Small amounts are excreted into breast-milk.
Magnesium crosses the placenta. Under physiologic conditions calcium is excreted in approximately equal amounts in urine and endogenous intestinal secretion. Parathyroid hormone, vitamin D and thiazide diuretics decrease urinary excretion of calcium, whereas other diuretics (loop diuretics), calcitonin and growth hormone promote renal excretion. Urinary calcium excretion decreases in early stages of renal failure. Urinary calcium excretion increases during pregnancy. Calcium is also excreted by the sweat glands. Calcium crosses the placenta and is excreted into breast-milk.
Standard genotoxicity studies have not been performed with Osvaren. Based on available data no genotoxic or carcinogenic potential have to be assumed.
No reproductive toxicity studies have been performed with this medicine.
© All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.
