Inhibition of iron absorption by omeprazole in rat model.

Since gastric acid is an important luminal factor in the absorption of non-heme iron, the effect of omeprazole on the absorption of iron in a rat model was studied. Iron absorption studies were performed on rats on a normal diet (N = 42) and rats fed an iron-deficient diet (N = 43) for three weeks. Rats were orally dosed with 40 mumol/kg of omeprazole or placebo daily for two days prior to iron absorption studies. Rats were orally dosed with 1 mmol of ferrous chloride, ferric chloride or food iron (dietary suspension) containing 11 micrograms of iron and labeled with 1 microCi of 59Fe. Omeprazole-treated rats on the normal diet had no significant reduction in the absorption of ferric, ferrous, or food iron. In the rats on the iron-deficient diet, the absorption of ferrous iron decreased from 76 +/- 7.5% (mean +/- SE) in control rats to 38 +/- 8.5% in the omeprazole-treated rats (P less than 0.003) and the absorption of food iron decreased from 65 +/- 7.5% in control rats to 37 +/- 6.5% in the omeprazole-treated rats (P less than 0.016). There was no significant reduction in the absorption of ferric iron. Omeprazole therapy is unlikely to be associated with significant iron malabsorption in normal patients but may reduce iron absorption in pathological states associated with increased iron absorption such as iron deficiency.