46: Iron

HISTORY AND EPIDEMIOLOGY

Iron poisoning has become uncommon. This success may underscore the importance of prevention by interventions gleaned from poison center data and poison prevention advocacy. Blister packaging, smaller dosages, and education of parents and health care professionals have led to a great decline in iron poisoning in the past two decades. Unfortunately, however, significant iron poisonings still occur, and clinician must be aware of the nuances of presentation and diagnosis to optimize iron poisoning management. Clinicians must be vigilant for signs of serious iron poisoning and be ready to intervene if gastrointestinal (GI) toxic effects are followed by acid–base disturbances, altered mental status, or hemodynamic compromise.

Iron salts such as ferrous sulfate have been used therapeutically for thousands of years and continue to be available, both with and without prescription, for the prevention and treatment of iron deficiency anemia in patients of all ages. Despite this long history of use, the first reports of iron toxicity only occurred in the mid-twentieth century. Since then, numerous cases of iron poisoning and fatalities have been reported, mostly in children.^57,59 In 1950, the manufacturer of “fersolate,” an iron supplement, included a package warning: “Excessive doses of iron can be dangerous. Do not leave these tablets within reach of young children, who may eat them as sweets with harmful results.”⁸⁷

The incidence of iron exposures continued to increase in the 1980s, ultimately becoming, in the 1990s, the leading cause of poisoning deaths reported to poison centers among children younger than 6 years (Chap. 136). This problem was publicized in a case series of tragic fatalities involving five toddlers in Los Angeles during a 6-month period in 1992, all of whom were exposed to prenatal vitamins containing iron.⁹⁴ The association between death and prenatal vitamins highlights the availability of these potentially lethal medications in the homes of families with young children, ironically as a result of more attentive prescribing of prenatal iron. A case control study in Canada identified a fourfold increase in the risk of iron poisoning to the older sibling of a newborn during the first postpartum month.⁴² The authors concluded that almost one-half of all hospital admissions of young children for iron poisoning could be prevented by safer storage of iron supplements in the year before and the year after the birth of a sibling.

In 1997, the US Food and Drug Administration (FDA) mandated that all iron salt-containing preparations display warning labels regarding the dangers of pediatric iron poisoning.²³ In addition to the warning labels, the FDA launched an educational campaign to alert caregivers and prescribers of the potential toxicity of iron supplements.²⁴ Other preventive initiatives instituted by the FDA in 1997 included unit dosing (blister packs) of prescriptions for preparations containing more than 30 mg of elemental iron and limitations on the number of pills dispensed (ie, maximum ...