A case of hypomagnesaemia due to malabsorption, unresponsive to oral administration of magnesium glycerophosphate, but responsive to oral magnesium oxide supplementation

Oral and intravenous replacement of minerals such as magnesium and calcium are usually straightforward in clinical practice, the choice generally being governed by the preparation most readily available. There are very few data comparing efficacy and absorption profiles of different magnesium salts. This case report highlights the importance of considering alternative preparations of oral magnesium salts in patients who appear unresponsive to one preparation, rather than moving on to chronic intravenous therapy via a Hickman line. In the case of patients with small bowel shortening, the use of magnesium oxide should be considered.