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PPI-Induced Hypomagnesaemia — ESENeph MCQ

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ModerateElectrolyte DisordersPPI-Induced HypomagnesaemiaESENeph

A 45-year-old man with CKD G3b has a serum magnesium of 0.55 mmol/L. He is on a PPI (Omeprazole 20 mg) long-term. What is the mechanism of PPI-induced hypomagnesaemia?

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Correct answer: B — PPIs impair intestinal magnesium absorption by altering TRPM6/7 channel activity in the colon – the mechanism is not fully elucidated but is related to altered luminal pH

Long-term proton pump inhibitor use can cause hypomagnesaemia through impaired intestinal absorption; altered TRPM6/7-mediated active transport is a proposed mechanism, although it is not fully established. Appropriately low urinary magnesium helps distinguish this from renal wasting. The MHRA advises considering magnesium measurement before and periodically during prolonged treatment, especially with digoxin or other medicines that lower magnesium. The unnecessary US regulatory attribution has been removed.

Reference: MHRA Drug Safety Update: proton pump inhibitors and hypomagnesaemia: https://www.gov.uk/drug-safety-update/proton-pump-inhibitors-in-long-term-use-reports-of-hypomagnesaemia