Chelation therapy

Template:Short description Template:Infobox medical intervention Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body.<ref name=crisponi>Template:Cite book</ref> Chelation therapy has a long history of use in clinical toxicology<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and remains in use for some very specific medical treatments, although it is administered under very careful medical supervision due to various inherent risks, including the mobilization of mercury and other metals through the brain and other parts of the body by the use of weak chelating agents that unbind with metals before elimination, exacerbating existing damage.<ref name=Atwood2008>Template:Cite journal</ref> To avoid mobilization, some practitioners of chelation use strong chelators, such as selenium, taken at low doses over a long period of time.

Chelation therapy must be administered with care as it has a number of possible side effects, including death.<ref name="acs">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In response to increasing use of chelation therapy as alternative medicine and in circumstances in which the therapy should not be used in conventional medicine, various health organizations have confirmed that medical evidence does not support the effectiveness of chelation therapy for any purpose other than the treatment of heavy metal poisoning.<ref name=acs/> Over-the-counter chelation products are not approved for sale in the United States.<ref name="FDA_2010_warning">Template:Cite press release</ref>

Medical uses

Chelation therapy is the preferred medical treatment for metal poisoning,<ref name=crisponi/><ref>Template:Cite journal</ref> including acute mercury, iron (including in cases of sickle-cell disease and thalassemia),<ref>Template:Cite journal</ref><ref>Template:Cite book</ref> arsenic, lead, uranium, plutonium and other forms of toxic metal poisoning. The chelating agent may be administered intravenously, intramuscularly, or orally, depending on the agent and the type of poisoning.<ref>Template:Citation</ref>

Chelating agents

There are a variety of common chelating agents with differing affinities for different metals, physical characteristics, and biological mechanism of action. For the most common forms of heavy metal intoxication – lead, arsenic, or mercury – a number of chelating agents are available. Dimercaptosuccinic acid (DMSA) has been recommended by poison control centers around the world for the treatment of lead poisoning in children.<ref>Template:Cite journal</ref> Other chelating agents, such as 2,3-dimercaptopropanesulfonic acid (DMPS) and alpha lipoic acid (ALA), are used in conventional and alternative medicine. Some common chelating agents are ethylenediaminetetraacetic acid (EDTA), 2,3-dimercaptopropanesulfonic acid (DMPS), and thiamine tetrahydrofurfuryl disulfide (TTFD). Calcium-disodium EDTA and DMSA are only approved for the removal of lead by the Food and Drug Administration while DMPS and TTFD are not approved by the FDA. These drugs bind to heavy metals in the body and prevent them from binding to other agents. They are then excreted from the body. The chelating process also removes vital nutrients such as vitamins C and E, therefore these must be supplemented.<ref>Template:Cite news</ref>Template:Unreliable medical source

The German Environmental Agency (Umweltbundesamt) listed DMSA and DMPS as the two most useful and safe chelating agents available.<ref>Template:Cite journal</ref>

Chelator	Used in
Dimercaprol (British anti-Lewisite; BAL)	acute arsenic poisoning<ref name=KatzungTrevor2008>Template:Cite book</ref> acute mercury poisoning<ref name=KatzungTrevor2008/> lead poisoning (in addition to EDTA)<ref name=KatzungTrevor2008/> Lewisite poisoning (for which it was developed as an antidote)
Dimercaptosuccinic acid (DMSA)	lead poisoning<ref name=KatzungTrevor2008/> arsenic poisoning<ref name=KatzungTrevor2008/> mercury poisoning<ref name=KatzungTrevor2008/>
Dimercapto-propane sulfonate (DMPS)	severe acute arsenic poisoning<ref name=KatzungTrevor2008/> severe acute mercury poisoning<ref name=KatzungTrevor2008/>
Penicillamine	Mainly in: copper toxicity<ref name=KatzungTrevor2008/> Occasionally adjunctive therapy in: gold toxicity<ref name=KatzungTrevor2008/> arsenic poisoning<ref name=KatzungTrevor2008/> lead poisoning<ref name=KatzungTrevor2008/> rheumatoid arthritis<ref name=KatzungTrevor2008/>
Ethylenediamine tetraacetic acid (calcium disodium versenate) (CaNa2-EDTA)	lead poisoning<ref name=KatzungTrevor2008/>
Deferoxamine, Deferasirox and Deferiprone	acute iron poisoning<ref name=KatzungTrevor2008/> iron overload<ref>Template:Cite book</ref>

Side effects

Template:Multiple issues When used properly in response to a diagnosis of harm from metal toxicity, side effects of chelation therapy include dehydration, low blood calcium, harm to kidneys, increased enzymes as would be detected in liver function tests, allergic reactions, and lowered levels of dietary elements.<ref name="toxicfive-4">Template:Citation, which cites

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|CitationClass=web }}</ref> When administered inappropriately, there are the additional risks of hypocalcaemia (low calcium levels), neurodevelopmental disorders, and death.<ref name="toxicfive-4"/>

History

Chelation therapy can be traced back to the early 1930s, when Ferdinand Münz, a German chemist working for I.G. Farben, first synthesized ethylenediaminetetraacetic acid (EDTA).<ref name=royalsociety>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Munz was looking for a replacement for citric acid as a water softener.<ref name=royalsociety/> Chelation therapy itself began during World War II when chemists at the University of Oxford searched for an antidote for lewisite, an arsenic-based chemical weapon.<ref name=royalsociety/> The chemists learned that EDTA was particularly effective in treating lead poisoning.<ref name=royalsociety/>

Following World War II, chelation therapy was used to treat workers who had painted United States naval vessels with lead-based paints.<ref name=royalsociety/> In the 1950s, Norman Clarke Sr. was treating workers at a battery factory for lead poisoning when he noticed that some of his patients had improved angina pectoris following chelation therapy.<ref>Template:Cite journal</ref> Clarke subsequently administered chelation therapy to patients with angina pectoris and other occlusive vascular disease and published his findings in The American Journal of the Medical Sciences in December 1956.<ref name=olszewer88>Template:Cite journal</ref> He hypothesized that "EDTA could dissolve disease-causing plaques in the coronary systems of human beings."<ref>Template:Cite journal</ref> In a series of 283 patients treated by Clarke et al. From 1956 to 1960, 87% showed improvement in their symptomatology.<ref name=olszewer88/> Other early medical investigators made similar observations of EDTA's role in the treatment of cardiovascular disease (Bechtel, 1956; Bessman, 1957; Perry, 1961; Szekely, 1963; Wenig, 1958: and Wilder, 1962). However, later systemic reviews found that chelation was no better than placebo in treating heart disease.

In the 1960s, BAL was modified into DMSA, a related dithiol with far fewer side effects.<ref name=Kalia2005>Template:Cite journal</ref> DMSA quickly replaced both BAL and EDTA as the primary treatment for lead, arsenic and mercury poisoning in the United States. Esters of DMSA have been developed which are reportedly more effective; for example, the monoisoamyl ester (MiADMSA) is reportedly more effective than DMSA at clearing mercury and cadmium.<ref name=Kalia2005/> Research in the former Soviet Union led to the introduction of DMPS, another dithiol, as a mercury-chelating agent. The Soviets also introduced ALA, which is transformed by the body into the dithiol dihydrolipoic acid, a mercury- and arsenic-chelating agent. DMPS has experimental status in the United States, while ALA is a common nutritional supplement.

Since the 1970s, iron chelation therapy has been used as an alternative to regular phlebotomy to treat excess iron stores in people with haemochromatosis.<ref name='CDC_Hemo'>Template:Citation</ref> Other chelating agents have been discovered. They all function by making several chemical bonds with metal ions, thus rendering them much less chemically reactive. The resulting complex is water-soluble, allowing it to enter the bloodstream and be excreted harmlessly.

In 1973, a group of practicing physicians created the Academy of Medical Preventics, later renamed the American College for Advancement in Medicine (ACAM).<ref name="olszewer88" /> The academy trains and certifies physicians in the safe administration of chelation therapy.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Members of the academy continued to use EDTA therapy for the treatment of vascular disease and developed safer administration protocols.<ref name="olszewer88" /> However, in 1998 the U.S. Federal Trade Commission (FTC) pursued the ACAM, an organization that promotes "complementary, alternative and integrative medicine" over the claims made regarding the treatment of atherosclerosis in advertisements for EDTA chelation therapy. The FTC concluded that there was a lack of scientific studies to support these claims and that the statements by the ACAM were false.<ref name= "FTC ACAM timeline">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In 1999, the ACAM agreed to stop presenting chelation therapy as effective in treating heart disease, avoiding legal proceedings.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }} {{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In 2010 the U.S. Food and Drug Administration (FDA) warned companies who sold over-the-counter (OTC) chelation products and stated that such "products are unapproved drugs and devices and that it is a violation of federal law to make unproven claims about these products. There are no FDA-approved OTC chelation products."<ref name=FDA_2010_warning/>

Controversies

Template:Update section Template:More medical citations needed {{ safesubst:#invoke:Unsubst||date=__DATE__ |$B= {{ safesubst:#invoke:Unsubst||date=__DATE__ |$B= Template:Ambox }} }} In 1998, the U.S. Federal Trade Commission (FTC) charged that the web site of the American College for Advancement in Medicine (ACAM) and a brochure they published had made false or unsubstantiated claims. In December 1998, the FTC announced that it had secured a consent agreement barring ACAM from making unsubstantiated advertising claims that chelation therapy is effective against atherosclerosis or any other disease of the circulatory system.<ref name= "FTC ACAM timeline"/><ref>Template:Cite press release</ref>

In August 2005, doctor error led to the death of a five-year-old boy with autism who was undergoing chelation therapy.<ref name=Atwood2008/> Others, including a three-year-old non-autistic girl and a non-autistic adult, have died while undergoing chelation therapy.<ref name=Atwood2008/> These deaths were due to cardiac arrest caused by hypocalcemia during chelation therapy. In two of the cases, hypocalcemia appears to have been caused by the administration of Na2EDTA (disodium EDTA) and in the third case the type of EDTA was unknown.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> Only the three-year-old girl had been found to have an elevated blood lead level and resulting low iron levels and anemia, which is the conventional medical cause for administration of chelation therapy.<ref>Template:Cite journal</ref>

According to protocol,<ref>Template:Cite journal</ref> EDTA should not be used in the treatment of children.<ref>Template:Cite bookTemplate:Unreliable medical sourceTemplate:Full citation needed</ref> More than 30 deaths have been recorded in association with IV-administered disodium EDTA since the 1970s.<ref name=Atwood2008/>

Use in alternative medicine

In alternative medicine, some practitioners claim chelation therapy can treat a variety of ailments, including heart disease and autism.<ref>Template:Cite journal</ref><ref name=Weber/> The use of chelation therapy by alternative medicine practitioners for behavioral and other disorders is considered pseudoscientific; there is no proof that it is effective.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Chelation therapy prior to heavy metal testing can artificially raise urinary heavy metal concentrations ("provoked" urine testing) and lead to inappropriate and unnecessary treatment.<ref name="toxicfive">Template:Citation</ref> The American College of Medical Toxicology and the American Academy of Clinical Toxicology warn the public that chelating drugs used in chelation therapy may have serious side effects, including liver and kidney damage, blood pressure changes, allergies and in some cases even death of the patient.<ref name="toxicfive"/>

Cancer

The American Cancer Society says of chelation therapy: "Available scientific evidence does not support claims that it is effective for treating other conditions such as cancer. Chelation therapy can be toxic and has the potential to cause kidney damage, irregular heartbeat, and even death."<ref name=acs/>

Cardiovascular disease

According to the findings of a 1997 systematic review, EDTA chelation therapy is not effective as a treatment for coronary artery disease and this use is not approved in the United States by the US Food and Drug Administration (FDA).<ref name="Ernst1997">Template:Cite journal</ref>

The American Heart Association stated in 1997 that there is "no scientific evidence to demonstrate any benefit from this form of therapy." The FDA, the National Institutes of Health (NIH) and the American College of Cardiology "all agree with the American Heart Association" that "there have been no adequate, controlled, published scientific studies using currently approved scientific methodology to support this therapy for cardiovascular disease."<ref name="Ernst1997"/> Template:Citation needed span{{ safesubst:#invoke:Unsubst||date=__DATE__ |$B= Template:Fix }}

A systematic review published in 2005 found that controlled scientific studies did not support chelation therapy for heart disease.<ref>Template:Cite journal</ref> It found that very small trials and uncontrolled descriptive studies have reported benefits while larger controlled studies have found results no better than placebo.

In 2009, the Montana Board of Medical Examiners issued a position paper concluding that "chelation therapy has no proven efficacy in the treatment of cardiovascular disease, and in some patients could be injurious."<ref name=MontanaBME>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The U.S. National Center for Complementary and Alternative Medicine (NCCAM) conducted a trial on the chelation therapy's safety and efficacy for patients with coronary artery disease.<ref name="TACT">Template:Cite journal</ref> NCCAM Director Stephen E. Straus cited the "widespread use of chelation therapy in lieu of established therapies, the lack of adequate prior research to verify its safety and effectiveness, and the overall impact of coronary artery disease" as factors motivating the trial.<ref>Template:Cite press release</ref> The study has been criticized by some who said it was unethical, unnecessary and dangerous, and that multiple studies conducted prior to it demonstrated that the treatment provides no benefit.<ref name="Atwood2008" />

The US National Center for Complementary and Alternative Medicine began the Trial to Assess Chelation Therapy (TACT) in 2003.<ref name="TACT" /> Patient enrollment was to be completed around July 2009<ref name="NCCAMQA">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> with final completion around July 2010,<ref name=TACT/> but enrollment in the trial was voluntarily suspended by organizers in September 2008 after the Office for Human Research Protections began investigating complaints such as inadequate informed consent.<ref name="washingtonpost">Template:Cite newsTemplate:Dead linkTemplate:Cbignore</ref> Additionally, the trial was criticized for lacking prior Phase I and II studies, and critics summarized previous controlled trials as having "found no evidence that chelation is superior to placebo for treatment of CAD or PVD."<ref name=Atwood2008/> The same critics argued that methodological flaws and lack of prior probability made the trial "unethical, dangerous, pointless, and wasteful."<ref name=Atwood2008/> The American College of Cardiology supported the trial and research to explore whether chelation therapy was effective in treating heart disease.<ref name=washingtonpost/> Evidence of insurance fraud and other felony convictions among (chelation proponent) investigators further undermined the credibility of the trial.<ref name="NIH-Fraudsters">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The final results of TACT were published in November 2012. The authors concluded that disodium EDTA chelation "modestly" reduced the risk of adverse cardiovascular outcomes among stable patients with a history of myocardial infarction.<ref>Template:Cite journal</ref> The study also showed a "marked" reduction in cardiovascular events in diabetic patients treated with EDTA chelation.<ref>Template:Cite journal</ref> An editorial published in the Journal of the American Medical Association said that "the study findings may provide novel hypotheses that merit further evaluation to help understand the pathophysiology of secondary prevention of vascular disease."<ref>Template:Cite journal</ref> Critics of the study characterized the study as showing no support for the use of chelation therapy in coronary heart disease, particularly the claims to reduce the need for coronary artery bypass grafting (CABG, pronounced "cabbage").<ref name="Attwood2012">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Gorski2012">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Autism

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Quackwatch says that autism is one of the conditions for which chelation therapy has been falsely promoted as effective, and practitioners falsify diagnoses of metal poisoning to trick parents into having their children undergo the risky process.<ref name="qw">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Template:As of, up to 7% of children with autism worldwide<ref name="Davis-review" /> had been subjected to chelation therapy.<ref name=stokstad>Template:Cite journal</ref> The death of two children in 2005 was caused by the administration of chelation treatments, according to the American Center for Disease Control. One of them had autism.<ref>Template:Cite news</ref> Parents either have a doctor use a treatment for lead poisoning, or buy unregulated supplements, in particular DMSA and lipoic acid.<ref name=stokstad/> Aspies For Freedom, an autism rights organization, considers this use of chelation therapy unethical and potentially dangerous.<ref name='AspFF'>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> There is little to no credible scientific research that supports the use of chelation therapy for the effective treatment of autism.<ref name=Weber>Template:Cite journal</ref><ref name="Davis-review">Template:Cite journal</ref><ref name="NYT_autism">Template:Cite news</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

See also

• List of ineffective cancer treatments
• Detoxification

External links

• Chelation Therapy: Unproven Claims and Unsound Theories - Quackwatch