Review article: metabolic consequences of long-term inhibition of acid secretion by omeprazole

Metabolic sequelae of profound and long-lasting inhibition of gastric acid secretion by omeprazole have largely been neglected. Data from long-term studies suggest that vitamin B12 stores decrease slightly over several years, although this was not clinically relevant within the first 4 years of therapy. Additionally, it cannot be completely ruled out that patients with an increased iron demand may develop iron deficiency, but data available at present do not provide any evidence that iron malabsorption is to be expected under normal conditions. Protein homeostasis and calcium metabolism seem to be unaffected by long-term omeprazole therapy. Based upon present experience, serum cobalamin concentration should be monitored in patients undergoing omeprazole therapy for several years.