The evolving use of arsenic in pharmacotherapy of malignant disease.

For more than 2,000 years, arsenic and its derivatives have shown medical utility. Owing to the toxicities and potential carcinogenicity of arsenicals, their popularity has fluctuated. The exact mechanism of action of therapeutic arsenic is not well characterized but likely to involve apoptosis, generation of reactive oxygen species, inhibition of intracellular transduction pathways, and cell functions. Arsenic trioxide has received approval for use in patients with relapsed acute promyelocytic leukemia for remission induction. Arsenic has additionally shown activity in a range of solid tumors, myelodysplastic syndrome, multiple myeloma, and in autoimmune diseases. The following is a review of the history of arsenic, its cellular metabolism, pharmacology, genetic basis of disposition, associated toxicities, and clinical efficacy.