Dangers of "EDTA"

This letter is intended to raise medical practitioners' awareness of the dangers of two similar sounding forms of edetate: edetate calcium disodium and edetate disodium. Edetate disodium has been reported as causing fatality when either confused with edetate calcium disodium or used outside of indication. This risk is currently increased in New Zealand due to difficulties in sourcing edetate calcium disodium and greater availability in hospital pharmacies of the disodium form.

Edetate (ethylenediamine tetraacetate, EDTA) is available as edetate calcium disodium (variously described as calcium disodium versenate, calcium disodium EDTA, sodium calcium edetate, calcium EDTA or Versenate) and as edetate disodium (also described as disodium EDTA or disodium edetate); either drug may simply be referred to as EDTA.

Both are parenterally administered chelating agents; albeit with differing uses and toxicity. Edetate calcium disodium is indicated for "the reduction of blood levels and depot stores of lead in lead poisoning (acute and chronic) and lead encephalopathy, in both paediatric and adult populations.";1 whereas edetate disodium has existing indications for use in "selected patients for the emergency treatment of hypercalcaemia and for the control of...