Arsenic trioxide poisoning: a description of two acute overdoses.

Arsenic is a traditional poison that has a history extending back into ancient times, as a medicinal agent, a homicidal poison and more recently in deliberate and unintentional self-poisoning. We report two cases of acute poisoning with an unwettable formulation of arsenic trioxide. Both patients had early gastrointestinal toxicity and were treated with early whole bowel irrigation (WBI). Chelation therapy with dimercaptosuccinic acid (dimercaptosuccinate, DMSA) was commenced within 24 hours and serial blood and urine arsenic concentrations were measured. Neither patient suffered any adverse outcome in spite of very high blood and urine concentrations of arsenic. Arsenic quantification in blood, urine and faeces suggested that enhanced gastrointestinal decontamination was minimally effective for decontamination and that DMSA for at least two weeks was required.