Hypomagnesaemia leading to parathyroid dysfunction, hypocalcaemia, and hypokalaemia as a complication of long-term treatment with a proton pump inhibitor - a literature review.

Proton pump inhibitors (PPIs) are one of the most frequently used medications worldwide. The side effects of this class of drugs have been widely studied. However, their impact on the electrolyte balance is frequently forgotten. Long-term PPI administration can lead to profound electrolyte disturbances, namely hypomagnesaemia as well as, secondary to very low magnesium levels, hypocalcaemia and hypokalaemia. In this paper we comprehensively review the complexity of the mechanisms contributing to electrolyte imbalance following PPI (proton pump inhibitors) by changing the pH in the intestinal lumen, interfering with the active cellular transport of magnesium regulated by the transient receptor potential melastatin cation channels TRPM6 and TRPM7. The accompanying hypomagnesaemia causes unblocking of the renal outer medullary potassium channel (ROMK), which results in increased potassium loss in the ascending limb of the loop of Henle. Hypokalaemia caused by hypomagnesaemia is resistant to potassium supplementation because the loss of this element in urine increases with the supply of potassium. Additionally, within the calcium-sensitive receptor (CASR), dissociation of magnesium from the alpha subunit of G protein caused by hypomagnesaemia increases its activity, leading to inhibition of PTH secretion and hypocalcaemia resistant to calcium supplementation. All this means that in some patients, chronic use of proton pump inhibitors by affecting the absorption of magnesium, may lead to life-threatening electrolyte disorders.