Serum iron, ferritin, and vitamin B12 during prolonged omeprazole therapy.

Since gastric acid plays an important role in the absorption process of iron and vitamin B12, we determined levels of iron, ferritin, vitamin B12, and folic acid in 75 serum samples obtained during continuous omeprazole therapy (6-48 months after start of therapy) from 34 patients with peptic diseases (primarily reflux esophagitis). Serum iron and ferritin levels were decreased in two and three patients, respectively, but there is little evidence that omeprazole administration was causally related to these findings. Serum vitamin B12 and folic acid levels were normal in all cases. We conclude that iron, vitamin B12, and folic acid malabsorption is unlikely to occur, at least within the initial 3-4 years of continuous omeprazole therapy.