Comparison of the toxicities of two iron formulations in a swine model

Objective: To describe the histopathologic and pharmacokinetic differences of acute iron poisoning between chewable multivitamins with iron and solid iron tablets in a swine model. Methods: This was a prospective, randomized, unblinded toxicity study of iron poisoning of two iron formulations in mal e Yorkshire pigs. Eight swine were randomized to receive 60 mg/kg of iron i n either solid iron tablets or chewable multivitamins with iron. Serum iron , arterial blood gases, and episodes of vomiting were recorded over a ten-h our period. Routine histologic evaluations of the esophagus, stomach, small intestine, large intestine, and liver were performed immediately after the study period. Pharmacokinetic analyses of area under the concentration-tim e curve (AUC), time to peak concentration, and peak serum iron concentratio n were performed. Results: There was no significant difference between the serum iron levels except at three and four hours. There was a significant h igher AUC in the chewable group compared with the solid group. Pathologic e valuation identified severe esophageal inflammation and focal erosion in th e solid iron tablet group in two of the four animals, compared with no foca l erosions and minimal esophageal inflammation in the chewable group. No si gnificant change was identified in the liver, small intestine, or large int estine in either group. Conclusions: These results demonstrate increased lo cal gastrointestinal toxicity following a large ingestion of solid iron tab lets in a swine model, compared with chewable multivitamins with iron. High er serum iron levels were identified in the animals that received chewable multivitamins with iron.