Changes in plasma and urine magnesium following Subcutaneous insulin

In 7 of 13 patients given subcutaneous insulin as part of the assessment of their endocrinological status, serum magnesium levels fell below the lower limit of the normal range for the laboratory 1 to 2 hours after insulin administration. This relative hypomagnesaemia was not accompanied by any change in the red cell magnesium concentration, and did not bear a close relationship to the degree of hypoglycaemia developed. During the 2 1/2 hour period following insulin therapy there was renal conservation of magnesium ion.