Activated charcoal and the absorption of ferrous sulfate in rats

The treatment of iron poisoning has typically not included the administration of activated charcoal due to the lack of evidence supporting its efficacy. Several in vitro studies have demonstrated good adsorption of iron in a variety of pH ranges that were comparable to those found with other drugs for which activated charcoal is clinically used. This study was designed to determine whether activated charcoal altered the gastrointestinal absorption of toxic doses of iron as ferrous sulfate in an in vivo model. Seventy-five male Sprague-Dawley rats were randomly assigned into 5 groups: control given only distilled water; 100 mg elemental iron and water; 1:1 charcoal to iron; 2:1 charcoal to iron; and 4:1 charcoal to iron. All treatments were administered consecutively by gavage within 5 min. Physiological measurements and blood samples were taken at 0, 1, 4 and 8 h after treatment. There were no consistent differences in physiological measurements among the 5 groups. Mean serum iron concentrations did not differ among Groups 2, 3, 4 and 5 at the 4 sampling times except at 1 h between Groups 4 and 5. The area under the curve for serum iron concentrations did not differ among the treatment groups. Activated charcoal did not alter the extent of iron absorption in the experimental model.