Chelation therapy | |
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Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body. [1] Chelation therapy has a long history of use in clinical toxicology [2] 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. [3] 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. [4] [5] 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. [4] Over-the-counter chelation products are not approved for sale in the United States. [6]
Chelation therapy is the preferred medical treatment for metal poisoning, [1] [7] including acute mercury, iron (including in cases of sickle-cell disease and thalassemia), [8] [9] 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. [10]
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. [11] 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. [12] [ unreliable medical source? ]
The German Environmental Agency (Umweltbundesamt) listed DMSA and DMPS as the two most useful and safe chelating agents available. [13]
Chelator | Used in |
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Dimercaprol (British anti-Lewisite; BAL) |
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Dimercaptosuccinic acid (DMSA) | |
Dimercapto-propane sulfonate (DMPS) | |
Penicillamine | Mainly in: Occasionally adjunctive therapy in: |
Ethylenediamine tetraacetic acid (calcium disodium versenate) (CaNa2-EDTA) | |
Deferoxamine, Deferasirox and Deferiprone |
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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. [16] When administered inappropriately, there are the additional risks of hypocalcaemia (low calcium levels), neurodevelopmental disorders, and death. [16]
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). [17] Munz was looking for a replacement for citric acid as a water softener. [17] 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. [17] The chemists learned that EDTA was particularly effective in treating lead poisoning. [17]
Following World War II, chelation therapy was used to treat workers who had painted United States naval vessels with lead-based paints. [17] 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. [18] 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. [19] He hypothesized that "EDTA could dissolve disease-causing plaques in the coronary systems of human beings." [20] In a series of 283 patients treated by Clarke et al. From 1956 to 1960, 87% showed improvement in their symptomatology. [19] 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).
In 1973, a group of practicing physicians created the Academy of Medical Preventics (now the American College for Advancement in Medicine). [19] The academy trains and certifies physicians in the safe administration of chelation therapy. [21] Members of the academy continued to use EDTA therapy for the treatment of vascular disease and developed safer administration protocols. [19]
In the 1960s, BAL was modified into DMSA, a related dithiol with far fewer side effects. [22] 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. [22] 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. [23] 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.
Calcium-disodium EDTA chelation has been studied by the U.S. National Center for Complementary and Alternative Medicine for treating coronary disease. [24] In 1998, the U.S. Federal Trade Commission (FTC) pursued the American College for Advancement in Medicine (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. [25] In 1999, the ACAM agreed to stop presenting chelation therapy as effective in treating heart disease, avoiding legal proceedings. [26] 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." [6]
This section needs to be updated. The reason given is: Almost all of the sources cited were published more than 10 years ago. WP:MEDRS prefers sources within the last 5 years or so.(May 2024) |
This article needs more reliable medical references for verification or relies too heavily on primary sources .(May 2024) |
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. [25] [27]
In August 2005, doctor error led to the death of a five-year-old boy with autism who was undergoing chelation therapy. [3] Others, including a three-year-old non-autistic girl and a non-autistic adult, have died while undergoing chelation therapy. [3] 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. [28] [29] 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. [30]
According to protocol, [31] EDTA should not be used in the treatment of children. [32] More than 30 deaths have been recorded in association with IV-administered disodium EDTA since the 1970s. [3]
In alternative medicine, some practitioners claim chelation therapy can treat a variety of ailments, including heart disease and autism. [33] [34] 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. [35] Chelation therapy prior to heavy metal testing can artificially raise urinary heavy metal concentrations ("provoked" urine testing) and lead to inappropriate and unnecessary treatment. [36] 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. [36]
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." [4]
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). [37]
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." [37] They speculate[ speculation? ] that any improvement among heart patients undergoing chelation therapy can be attributed to the placebo effect and generally recommended lifestyle changes such as "quitting smoking, losing weight, eating more fruits and vegetables, avoiding foods high in saturated fats and exercising regularly." They also are concerned that patients could put off proven treatments for heart disease like drugs or surgery.[ citation needed ][ dubious – discuss ]
A systematic review published in 2005 found that controlled scientific studies did not support chelation therapy for heart disease. [38] 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." [39]
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. [40] 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. [41] 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. [3]
The US National Center for Complementary and Alternative Medicine began the Trial to Assess Chelation Therapy (TACT) in 2003. [40] Patient enrollment was to be completed around July 2009 [24] with final completion around July 2010, [40] 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. [42] 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." [3] The same critics argued that methodological flaws and lack of prior probability made the trial "unethical, dangerous, pointless, and wasteful." [3] The American College of Cardiology supported the trial and research to explore whether chelation therapy was effective in treating heart disease. [42] Evidence of insurance fraud and other felony convictions among (chelation proponent) investigators further undermined the credibility of the trial. [43]
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. [44] The study also showed a "marked" reduction in cardiovascular events in diabetic patients treated with EDTA chelation. [45] 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." [46] 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"). [47] [48] [49]
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. [50] As of 2008 [update] , up to 7% of children with autism worldwide [51] had been subjected to chelation therapy. [52] 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. [53] Parents either have a doctor use a treatment for lead poisoning, or buy unregulated supplements, in particular DMSA and lipoic acid. [52] Aspies For Freedom, an autism rights organization, considers this use of chelation therapy unethical and potentially dangerous. [54] There is little to no credible scientific research that supports the use of chelation therapy for the effective treatment of autism. [34] [51] [55] [56] [57] [58] [59]
Chelation is a type of bonding of ions and their molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate ligand and a single central metal atom. These ligands are called chelants, chelators, chelating agents, or sequestering agents. They are usually organic compounds, but this is not a necessity.
Ethylenediaminetetraacetic acid (EDTA), also called EDTA acid, is an aminopolycarboxylic acid with the formula [CH2N(CH2CO2H)2]2. This white, slightly water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-soluble complexes even at neutral pH. It is thus used to dissolve Fe- and Ca-containing scale as well as to deliver iron ions under conditions where its oxides are insoluble. EDTA is available as several salts, notably disodium EDTA, sodium calcium edetate, and tetrasodium EDTA, but these all function similarly.
Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashes, anxiety, memory problems, trouble speaking, trouble hearing, or trouble seeing. High-level exposure to methylmercury is known as Minamata disease. Methylmercury exposure in children may result in acrodynia in which the skin becomes pink and peels. Long-term complications may include kidney problems and decreased intelligence. The effects of long-term low-dose exposure to methylmercury are unclear.
Atorvastatin is a statin medication used to prevent cardiovascular disease in those at high risk and to treat abnormal lipid levels. For the prevention of cardiovascular disease, statins are a first-line treatment. It is taken by mouth.
Interventional cardiology is a branch of cardiology that deals specifically with the catheter based treatment of structural heart diseases. Andreas Gruentzig is considered the father of interventional cardiology after the development of angioplasty by interventional radiologist Charles Dotter.
Dimercaprol, also called British anti-Lewisite (BAL), is a medication used to treat acute poisoning by arsenic, mercury, gold, and lead. It may also be used for antimony, thallium, or bismuth poisoning, although the evidence for those uses is not very strong. It is given by injection into a muscle.
An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term complication is similar to adverse effect, but the latter is typically used in pharmacological contexts, or when the negative effect is expected or common. If the negative effect results from an unsuitable or incorrect dosage or procedure, this is called a medical error and not an adverse effect. Adverse effects are sometimes referred to as "iatrogenic" because they are generated by a physician/treatment. Some adverse effects occur only when starting, increasing or discontinuing a treatment. Using a drug or other medical intervention which is contraindicated may increase the risk of adverse effects. Adverse effects may cause complications of a disease or procedure and negatively affect its prognosis. They may also lead to non-compliance with a treatment regimen. Adverse effects of medical treatment resulted in 142,000 deaths in 2013 up from 94,000 deaths in 1990 globally.
Succimer, sold under the brand name Chemet among others, is a medication used to treat lead, mercury, and arsenic poisoning. When radiolabeled with technetium-99m, it is used in many types of diagnostic testing. A full course of Succimer lasts for 19 days of oral administration. A second course should be given when more than two weeks pass after the first course.
Percutaneous coronary intervention (PCI) is a minimally invasive non-surgical procedure used to treat narrowing of the coronary arteries of the heart found in coronary artery disease. The procedure is used to place and deploy coronary stents, a permanent wire-meshed tube, to open narrowed coronary arteries. PCI is considered 'non-surgical' as it uses a small hole in a peripheral artery (leg/arm) to gain access to the arterial system, an equivalent surgical procedure would involve the opening of the chest wall to gain access to the heart area. The term 'coronary angioplasty with stent' is synonymous with PCI. The procedure visualises the blood vessels via fluoroscopic imaging and contrast dyes. PCI is performed by an interventional cardiologists in a catheterization laboratory setting.
Paul M. Ridker is a cardiovascular epidemiologist and biomedical researcher. He is currently the Eugene Braunwald Professor of Medicine at Harvard University and Brigham and Women's Hospital, where he directs the Center for Cardiovascular Disease Prevention. Ridker also holds an appointment as Professor in the Department of Epidemiology at the Harvard T.H. Chan School of Public Health.
Concerns about thiomersal and vaccines are commonly expressed by anti-vaccine activists. Claims relating to the safety of thiomersal, a mercury-based preservative used in vaccines, are refuted, but still subject to fearmongering, notably claims it could cause neurological disorders such as autism, leading to its removal from most vaccines in the US childhood schedule. This had no effect on the rates of diagnosis of pervasive developmental defects, including autism. Extensive scientific research shows no credible evidence linking thiomersal to such conditions.
Dexrazoxane hydrochloride, sold under the brand name Zinecard among others, is a cardioprotective agent. It was discovered in 1972. The IV administration of dexrazoxane is in acidic condition with HCl adjusting the pH.
A drug-eluting stent (DES) is a tube made of a mesh-like material used to treat narrowed arteries in medical procedures both mechanically and pharmacologically. A DES is inserted into a narrowed artery using a delivery catheter usually inserted through a larger artery in the groin or wrist. The stent assembly has the DES mechanism attached towards the front of the stent, and usually is composed of the collapsed stent over a collapsed polymeric balloon mechanism, the balloon mechanism is inflated and used to expand the meshed stent once in position. The stent expands, embedding into the occluded artery wall, keeping the artery open, thereby improving blood flow. The mesh design allows for stent expansion and also for new healthy vessel endothelial cells to grow through and around it, securing it in place.
2,3-Dimercapto-1-propanesulfonic acid and its sodium salt are chelating agents that form complexes with various heavy metals. They are related to dimercaprol, which is another chelating agent.
Metal toxicity or metal poisoning is the toxic effect of certain metals in certain forms and doses on life. Some metals are toxic when they form poisonous soluble compounds. Certain metals have no biological role, i.e. are not essential minerals, or are toxic when in a certain form. In the case of lead, any measurable amount may have negative health effects. There is a popular misconception that only heavy metals can be toxic, but lighter metals such as beryllium and lithium can be toxic too. Not all heavy metals are particularly toxic, and some are essential, such as iron. The definition may also include trace elements when abnormally high doses may be toxic. An option for treatment of metal poisoning may be chelation therapy, a technique involving the administration of chelation agents to remove metals from the body.
A coronary stent is a tube-shaped device placed in the coronary arteries that supply blood to the heart, to keep the arteries open in patients suffering from coronary heart disease. The vast majority of stents used in modern interventional cardiology are drug-eluting stents (DES). They are used in a medical procedure called percutaneous coronary intervention (PCI). Coronary stents are divided into two broad types: drug-eluting and bare metal stents. As of 2023, drug-eluting stents were used in more than 90% of all PCI procedures. Stents reduce angina and have been shown to improve survival and decrease adverse events after a patient has suffered a heart attack—medically termed an acute myocardial infarction.
Ticagrelor, sold under the brand name Brilinta among others, is a medication used for the prevention of stroke, heart attack and other events in people with acute coronary syndrome, meaning problems with blood supply in the coronary arteries. It acts as a platelet aggregation inhibitor by antagonising the P2Y12 receptor. The drug is produced by AstraZeneca.
Steven E. Nissen is an American cardiologist, researcher and patient advocate. He was chairman of cardiovascular medicine at the Cleveland Clinic, in Cleveland, Ohio.
Jeffrey A. Brent is a medical toxicologist who is a distinguished clinical professor of medicine and emergency medicine at the University of Colorado, School of Medicine. In addition, he is a professor at the Department of Environmental and Occupational Health at the Colorado School of Public Health. He is also the past president of the American Academy of Clinical Toxicology, was editor in chief of the journal Toxicological Reviews, and was a member of the board of directors of the American College of Medical Toxicology. Previously, most of Brent's research focused on the use of fomepizole as a treatment for both methanol and ethylene glycol poisoning, and he led a trial of this drug which resulted in the FDA approving it in December 1997. Currently, Brent serves as Director of the Toxicology Investigators Consortium, an NIH and FDA supported multi center research and surveillance group. Brent is also a senior editor of "Critical Care Toxicology: Diagnosis and Management of the Critically Poisoned Patient," originally published in 2005, and now in its second edition, which was published in 2017.
Kimball C. Atwood IV is an American medical doctor and researcher from Newton, Massachusetts. He is retired as an assistant clinical professor at Tufts University School of Medicine and anesthesiologist at Newton-Wellesley Hospital.
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: CS1 maint: multiple names: authors list (link)However, given the significant methodological limitations of these studies, the research reviewed here does not support the use of chelation as a treatment for ASD