Comment on “Ingestion of slow-release iron treated with gastric lavage – never say late”

Comment on “Ingestion of slow-release iron treated with gastric lavage – never say late”

To The Editor:

The report by Goldstein and Berkovitch in Clinical Toxicology 44(3) suggests that gastric lavage, a nearly abandoned procedure, may play a role in patients presenting hours after an overdose of iron tablets. The authors conclude that “gastric lavage in this case prevented further progression of the iron into the small bowel, and further absorption” (1). But the data they present do not necessarily support this conclusion.

The authors describe the case of a 15-year-old girl whom they treated six hours after she had ingested “20 slow release iron tablets.” They do not provide the composition of these tablets, but typical pills of this type contain ferrous sulfate 160 mg, equivalent to 32 mg elemental iron. If we assume that the patient was a small 15-year-old weighing 40 kg, she would have consumed, according to the authors' history, 640 mg or 16 mg/kg of elemental iron. Although ingestions of less than 20 mg/kg elemental iron may result in gastric upset, significant toxicity typically occurs at doses greater than 40 mg/kg and is associated with peak serum iron levels greater than 500 mcg/dl (2).

The authors noted an opacity on the abdominal film consistent with a conglomerate of iron tablets in the stomach that disappeared after gastric lavage. But in the absence of further evidence, it is by no means clear that lavage actually removed the iron from the GI tract. Without analysis of the gastric aspirate for iron content it is just as likely that the lavage procedure broke up the conglomerate and propelled the iron, now dispersed and radiolucent, into the small bowel. A canine study of radiographs after iron ingestion found that radiopaque material was not seen “once the tablets had dissolved or become smaller than course granules” (3). Gastric lavage can potentially disrupt a drug bezoar, increasing surface area and promoting absorption (4). Goldstein and Berkovitch cite the fact that the patient's iron level peaked at 250 mcg/dl as evidence of successful removal. But if the patient had indeed ingested 16 mg/kg of elemental iron we would not expect her to have a toxic level, regardless of whether the iron was removed or washed into the small bowel.

Finally, the authors state that common medications that are radiopaque on abdominal film include aspirin, amitryptiline, chlorpromazine, and spironolactone. However one of the references they cite to support this claim, a study of drug radiopacity in a cadaver model, demonstrated that aspirin, chlorpromazine and spironolactone are radiolucent, while a perphenazine/amitryptiline combination pill is only weakly radiopaque (5).

It is no accident that gastric lavage has fallen out of favor. Multiple studies have failed to demonstrate a benefit to clinical outcome that would justify the risks of the procedure (6–8) and the ineffectiveness of gastric lavage in iron overdose has been reported (9). A study of patients with tricyclic antidepressant overdose in which gastric aspirate was analyzed failed to demonstrate more than trivial drug recovery despite large volume lavage (10). It is possible that gastric lavage may have a role to play in the management of patients with gastric concretions after an overdose. More data, specifically documentation of drug recovery in the lavage fluid, should be obtained before this procedure is recommended.