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Medical Use of Chelators
One of the first uses of chelators for a
medical purpose was the use of dimercaprol (British anti-lewisite/BAL) to treat arsenic poisoning caused by the
poison gas lewisite during World War II. Following the war, chelating
agents (mainly EDTA) were used to treat toxicity caused by mercury, lead, and
other heavy metals. EDTA successfully reduced serum calcium levels in
patients with hypercalcemia. Later in the post war era, chelating agents
were explored as possible chemotherapeutic agents and agents to treat radiation
poisoning.
In the early 1960's, EDTA was used to treat premature
ventricular contractions and in digoxin poisoning before it was later replaced
by better therapies. It was also during this time that artherosclerotic
heart disease began to be widely researched; the idea that chelation therapy
could be used to fight this disease was also proposed during this time.
Other chelators have been proposed to have medical uses. Tymianski has researched the usefulness of
BAPTA-AM (similar to EDTA) as a chelating agent that binds calcium inside
neurons, thereby reducing "excitotoxic and ischemic neuronal
injury". Ongoing research is exploring the potential of
chelating agents in preventing ischemic injury induced by high levels of
calcium-dependent enzymes.
There are a wide variety of therapeutic
claims made by supporters of chelation therapy that fall outside the paradigm of
the conventional medical uses of chelators. It is important to examine
these claims and to make informed decisions when deciding how to use chelation
therapy. Interestingly a common addition to a course IV or oral chelation
therapy for treatment of cardiovascular disease is the recommendation that the
patient make significant changes in their diet and exercise and quit smoking,
which are universal recommendations for patients with cardiovascular disease. |
