[An unknown but potentially serious side effect of proton pump inhibitors: hypomagnesaemia].

Long-term use of proton pump inhibitors can lead to serious hypomagnesaemia. Intestinal magnesium absorption takes place by passive paracellular and active transcellular transport. It has been hypothesized that proton pump inhibitors impair the active transcellular magnesium transport. The resulting hypomagnesaemia may cause hypoparathyroidism, hypocalcaemia and hypokalaemia. Proton pump inhibitor-induced hypomagnesaemia is reversible: it resolves when proton pump inhibitors are stopped. The indication for long-term proton pump inhibitor treatment should be evaluated periodically.