Continuing Education Activity
Ethylenediaminetetraacetic acid (EDTA) is a medication used in the management and treatment of heavy metal toxicity. It is in the chelating class of drugs. This activity outlines and reviews the indications, actions, and contraindications for what is EDTA as a valuable agent in managing lead toxicity. This activity will highlight the mechanism of action, side effect profile, and other key factors such as dosing, pharmacokinetics, and monitoring pertinent for members of the healthcare team in the use of EDTA.

Ethylenediaminetetraacetic acid (EDTA, edetate calcium disodium, calcium disodium versenate) is a chelation agent used for heavy metal toxicity. EDTA, which was first synthesized in the mid-1930s, has non-pharmacologic and pharmacologic purposes. As a pharmacologic agent, what is EDTA used as calcium disodium edetate, which prevents it from binding calcium in the body. Another form, edetate disodium, has a markedly improved ability to bind calcium; this form is no longer used for chelation therapy due to the high risk for hypocalcemia. As a non-pharmacologic agent, EDTA is used in many different industries to remove toxic metal ions. It is commonly used in the cosmetic and food industry and has many applications within scientific laboratories.

Currently, EDTA is FDA-approved for the treatment of lead poisoning in adults and children. EDTA has the ability to bind lead tightly and is more effective than other common chelators. EDTA is also used in a diagnostic test to assess levels of lead present within patients. The lead mobilization test is performed by administering 2 grams of EDTA through the intravenous or intramuscular route. Patients have a positive lead mobilization test if, in the following 24 hours, they excrete more than 6 grams of lead in their urine. The lead mobilization test allows clinicians to have a more accurate total body lead level and further guide treatment with chelation agents. While not approved by the FDA, EDTA has the ability to bind other heavy metals within the body, including zinc, cadmium, mercury, and iron. Many cases have been reported where EDTA is used to bind other toxic metals, forming a soluble compound that allows excretion through the urine.
While limited, there have been reports of what is EDTA being beneficial to reduce coronary artery disease. With the negative effects of heavy metals on the cardiovascular system, EDTA has been proposed as a useful agent against the development of atherosclerosis. Additionally, edetate disodium has a high affinity for calcium within the body. It is thought that chelation therapy might be beneficial by scavenging the calcium present within fatty, atherosclerotic deposits. Heavy metals have the ability to produce reactive agents within the body that lead to an inflammatory cascade. The various cytokines and inflammatory agents have negative effects on the nervous system and can lead to neurotoxicity. Calcium disodium edetate can be useful for the management of certain neurodegenerative disorders. By chelating metal ions, further inflammatory changes are prevented from taking place.

Chelation agents function by forming bonds with various metal ions, including calcium, zinc, lead, etc. After these bonds are formed, a soluble chelate-metal complex is created that can be excreted from the body. In a similar method, EDTA has a complex structure that allows it to bind various metals. The molecular composition of what is EDTA consists of multiple oxygen molecules, which function to donate electrons and form coordination complexes with metal ions. When calcium disodium edetate binds to metals, the calcium is displaced from the structure. The bonds formed with the metals are extremely strong and prevent further toxic effects from occurring before excretion out of the body.