Absorption of iron after experimental overdose of chewable vitamins.

Even though ingestion of chewable iron preparations is much more common, treatment recommendations for iron overdose are usually based on experience with nonchewable preparations. To determine the optimal time to measure serum iron concentrations, five volunteers were given chewable iron in 5 mg/kg and 10 mg/kg doses and their serum iron concentrations monitored. Peak levels occurred at 4.2 and 4.5 hours, respectively, after ingestion, and levels drawn at 3 hours were within 90% of the peak. Nausea and headache were experienced by all volunteers, and serum iron exceeded baseline total iron binding capacity in two subjects at the 10 mg/kg dose. In minor iron overdose resulting from the ingestion of chewable vitamins, serum iron concentrations measured between 3 and 7 hours (95% confidence level of peak concentrations) may be adequate in assessing the peak serum iron concentration.