assessment and treatment

Last reviewed 01/2018

Assessment of deficiency is necessary as serum levels are less useful as magnesium is more important inside than outside of the cells. Deficiency is indicated by:

  • failure to excrete more than 70% of an administered load of 20 mmol Mg within 16 hours; OR
  • failure to excrete more than 80% if 0.25 mmol per Kg iv. over 1 - 2 hours

Treatment:

  • oral magnesium salts - magnesium glycerophosphate least likely to cause diarrhoea
  • parenteral magnesium sulphate