NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update

Magnesium Replacement Therapy

Magnesium aspartate dihydrate sachets (Magnaspartate®) have been added to the GGC Adult Formulary for the treatment and prevention of magnesium deficiency, as diagnosed by a doctor. This is the first licensed oral preparation and is the preferred product for oral replacement. Each Magnaspartate® sachet contains 243mg (10 mmol) of magnesium.


The GGC Guideline for the management of hypomagnesaemia is currently being updated. The guideline notes that it is clinically important to establish and then correct the cause of hypomagnesaemia if possible. Magnesium deficiency has been associated with gastrointestinal loss (eg malabsorption, malnutrition, Crohn's disease, coeliac disease, stoma or fistula), chronic alcoholism, renal disorders and drug therapy (eg PPIs, diuretics, gentamicin, ciclosporin, amphotericin)


There is no robust evidence of the superiority of one oral magnesium preparation over another. If the licensed product is not effective or is poorly tolerated, eg dose limiting diarrhoea, it would be reasonable to try an alternative unlicensed oral preparation, if the patient’s condition allows. Information from the small studies available suggests there are differences in the bioavailability of some magnesium salts, thus caution should be exercised when switching between magnesium preparations. Your local pharmacy team can provide advice on other options if required.