Intracellular magnesium loss after diuretic administration.

Diuretic agents influence the renal handling of magnesium, causing increased losses of the ion. Continuing magnesium losses may, in the long term, result in a magnesium deficiency. 296 patients with congestive heart failure or arterial hypertension receiving long term diuretic therapy were studied by skeletal muscle biopsies to assess their magnesium status. 65% of the congestive heart failure patients and 42% of the patients with arterial hypertension were found to have subnormal values for skeletal muscle magnesium. Studies with the potassium-sparing diuretics amiloride, spironolactone and triamterene demonstrate that these drugs significantly increase the muscle magnesium content in patients on long term diuretic treatment for congestive heart failure and/or arterial hypertension--in addition to their well known positive effect on potassium balance.