Magnesium metabolism.

Magnesium is the second most abundant intracellular cation in the human body and is necessary as a cofactor in more than 300 enzymatic reactions. The generation and use of adenosine triphosphate is dependent on the presence of magnesium. The assessment of the magnesium status of a patient is problematic because there are no easily performed tests that reliably predict the intracellular concentration. There are recognized molecular and cellular actions of magnesium that explain clinically recognizable problems when a magnesium deficiency or excess is present. Guidelines for therapy of magnesium deficiency are given. Future directions in research are given.