Endocrine Abstracts

An association between the use of proton pump inhibitors (PPIs) and profound hypomagnesaemia has been highlighted in a number of case reports. As the prevalence of this occurrence or cause remain unknown, we undertook a review of patients with significant hypomagnesaemia in our hospital with a particular focus on use of PPIs and management.

35 patients (21f; mean age (S.D.): 71.3 (14.6); median: 74 years) with significant hypomagnesaemia (defined as serum Mg <0.5 mmol/l, adjusted for albumin), for whom medical records were available, were identified from the laboratory computer. Information was extracted on serum Mg level, presentation, identified cause and treatment.

Serum Mg levels were 0.17–0.49 mmol/l (mean (S.D.): 0.30 (0.08); median 0.32); calcium levels were 1.35–2.61 mmol/l (mean (S.D.): 1.91 (0.33); median 1.93 mmol/l). 26/35 patients were prescribed PPI’s – there was no difference between Mg or Ca levels for those on PPIs compared to the group as a whole.

Use of PPIs was deemed causative or contributory in 12 of 26, 7 of whom were switched to an alternative antacid, three were stopped and two continued. Other causes documented included GI loss in eight, chemotherapy in five, renal losses in three, alcohol abuse four, with no cause documented in 10.

There was lack of standardisation of treatment - for the group, 17, including nine in whom PPIs were considered causative, received IV replacement (duration: 30 min-4d; dose 20–96 mmol, mean (S.D.): 43.2 (27.5); median 40 mmol); two also received oral treatment (magnesium glycerophosphate 8 mmol tds). Of the remaining 19, four received oral replacement (three magnesium glycerophosphate 8 mmol tds, one unknown).

This short review shows PPI use to be common among patients with significant hypomagnesaemia, though it was considered as a contributory or causative factor in less than 50%. It also highlights a lack of standardisation in Magnesium replacement.