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Chelation therapy for acute inorganic mercury poisoning can be done with DMSA, 2,3-dimercapto-1-propanesulfonic acid (DMPS), -penicillamine (DPCN), or dimercaprol (BAL). Only DMSA is FDA-approved for use in children for treating mercury poisoning. However, several studies found no clear clinical benefit from DMSA treatment for poisoning due to mercury vapor. No chelator for methylmercury or ethylmercury is approved by the FDA; DMSA is the most frequently used for severe methylmercury poisoning, as it is given orally, has fewer side-effects, and has been found to be superior to BAL, DPCN, and DMPS. α-Lipoic acid (ALA) has been shown to be protective against acute mercury poisoning in several mammalian species when it is given soon after exposure; correct dosage is required, as inappropriate dosages increase toxicity. Although it has been hypothesized that frequent low dosages of ALA may have potential as a mercury chelator, studies in rats have been contradictory. Glutathione and "N"-acetylcysteine (NAC) are recommended by some physicians, but have been shown to increase mercury concentrations in the kidneys and the brain.
Chelation therapy can be hazardous if administered incorrectly. In August 2005, an incorrect form of EDTA (edetate disodium) used for chelation therapy resulted in hypocalcemia, causing cardiac arrest that killed a five-year-old autistic boy.
Experimental findings have demonstrated an interaction between selenium and methylmercury, but epidemiological studies have found little evidence that selenium helps to protect against the adverse effects of methylmercury.
The mainstays of treatment are removal from the source of lead and, for people who have significantly high blood lead levels or who have symptoms of poisoning, chelation therapy. Treatment of iron, calcium, and zinc deficiencies, which are associated with increased lead absorption, is another part of treatment for lead poisoning. When lead-containing materials are present in the gastrointestinal tract (as evidenced by abdominal X-rays), whole bowel irrigation, cathartics, endoscopy, or even surgical removal may be used to eliminate it from the gut and prevent further exposure. Lead-containing bullets and shrapnel may also present a threat of further exposure and may need to be surgically removed if they are in or near fluid-filled or synovial spaces. If lead encephalopathy is present, anticonvulsants may be given to control seizures, and treatments to control swelling of the brain include corticosteroids and mannitol. Treatment of organic lead poisoning involves removing the lead compound from the skin, preventing further exposure, treating seizures, and possibly chelation therapy for people with high blood lead concentrations.
A chelating agent is a molecule with at least two negatively charged groups that allow it to form complexes with metal ions with multiple positive charges, such as lead. The chelate that is thus formed is nontoxic and can be excreted in the urine, initially at up to 50 times the normal rate. The chelating agents used for treatment of lead poisoning are edetate disodium calcium (CaNaEDTA), dimercaprol (BAL), which are injected, and succimer and d-penicillamine, which are administered orally.
Chelation therapy is used in cases of acute lead poisoning, severe poisoning, and encephalopathy, and is considered for people with blood lead levels above 25 µg/dL. While the use of chelation for people with symptoms of lead poisoning is widely supported, use in asymptomatic people with high blood lead levels is more controversial. Chelation therapy is of limited value for cases of chronic exposure to low levels of lead. Chelation therapy is usually stopped when symptoms resolve or when blood lead levels return to premorbid levels. When lead exposure has taken place over a long period, blood lead levels may rise after chelation is stopped because lead is leached into blood from stores in the bone; thus repeated treatments are often necessary.
People receiving dimercaprol need to be assessed for peanut allergies since the commercial formulation contains peanut oil. Calcium EDTA is also effective if administered four hours after the administration of dimercaprol. Administering dimercaprol, DMSA (Succimer), or DMPS prior to calcium EDTA is necessary to prevent the redistribution of lead into the central nervous system. Dimercaprol used alone may also redistribute lead to the brain and testes. An adverse side effect of calcium EDTA is renal toxicity. Succimer (DMSA) is the preferred agent in mild to moderate lead poisoning cases. This may be the case in instances where children have a blood lead level >25μg/dL. The most reported adverse side effect for succimer is gastrointestinal disturbances. It is also important to note that chelation therapy only lowers blood lead levels and may not prevent the lead-induced cognitive problems associated with lower lead levels in tissue. This may be because of the inability of these agents to remove sufficient amounts of lead from tissue or inability to reverse preexisting damage.
Chelating agents can have adverse effects; for example, chelation therapy can lower the body's levels of necessary nutrients like zinc. Chelating agents taken orally can increase the body's absorption of lead through the intestine.
Chelation challenge, also known as provocation testing, is used to indicate an elevated and mobilizable body burden of heavy metals including lead. This testing involves collecting urine before and after administering a one-off dose of chelating agent to mobilize heavy metals into the urine. Then urine is analyzed by a laboratory for levels of heavy metals; from this analysis overall body burden is inferred. Chelation challenge mainly measures the burden of lead in soft tissues, though whether it accurately reflects long-term exposure or the amount of lead stored in bone remains controversial. Although the technique has been used to determine whether chelation therapy is indicated and to diagnose heavy metal exposure, some evidence does not support these uses as blood levels after chelation are not comparable to the reference range typically used to diagnose heavy metal poisoning. The single chelation dose could also redistribute the heavy metals to more sensitive areas such as central nervous system tissue.
Specific treatments for acute pesticide poisoning are often dependent on the pesticide or class of pesticide responsible for the poisoning. However, there are basic management techniques that are applicable to most acute poisonings, including skin decontamination, airway protection, gastrointestinal decontamination, and seizure treatment.
Decontamination of the skin is performed while other life-saving measures are taking place. Clothing is removed, the patient is showered with soap and water, and the hair is shampooed to remove chemicals from the skin and hair. The eyes are flushed with water for 10–15 minutes. The patient is intubated and oxygen administered, if necessary. In more severe cases, pulmonary ventilation must sometimes be supported mechanically. Seizures are typically managed with lorazepam, phenytoin and phenobarbitol, or diazepam (particularly for organochlorine poisonings).
Gastric lavage is not recommended to be used routinely in pesticide poisoning management, as clinical benefit has not been confirmed in controlled studies; it is indicated only when the patient has ingested a potentially life-threatening amount of poison and presents within 60 minutes of ingestion. An orogastric tube is inserted and the stomach is flushed with saline to try to remove the poison. If the patient is neurologically impaired, a cuffed endotracheal tube inserted beforehand for airway protection. Studies of poison recovery at 60 minutes have shown recovery of 8%–32%. However, there is also evidence that lavage may flush the material into the small intestine, increasing absorption. Lavage is contra-indicated in cases of hydrocarbon ingestion.
Activated charcoal is sometimes administered as it has been shown to be successful with some pesticides. Studies have shown that it can reduce the amount absorbed if given within 60 minutes, though there is not enough data to determine if it is effective if time from ingestion is prolonged. Syrup of ipecac is not recommended for most pesticide poisonings because of potential interference with other antidotes and regurgitation increasing exposure of the esophagus and oral area to the pesticide.
Urinary alkalinisation has been used in acute poisonings from chlorophenoxy herbicides (such as 2,4-D, MCPA, 2,4,5-T and mecoprop); however, evidence to support its use is poor.
Therapy is supportive and includes removal from further beryllium exposure. For very severe cases mechanical ventilation may be required.
Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body. Chelating agents are molecules that have multiple electron-donating groups, which can form stable coordination complexes with metal ions. Complexation prevents the metal ions from reacting with molecules in the body, and enable them to be dissolved in blood and eliminated in urine. It should only be used in people who have a diagnosis of metal intoxication. That diagnosis should be validated with tests done in appropriate biological samples.
Chelation therapy is administered under very careful medical supervision due to various inherent risks. When the therapy is administered properly, the chelation drugs have significant side effects. Chelation administered inappropriately can cause neurodevelopmental toxicity, increase risk of developing cancer, and cause death; chelation also removes essential metal elements and requires measures to prevent their loss.
The United States standard cyanide antidote kit first uses a small inhaled dose of amyl nitrite, followed by intravenous sodium nitrite, followed by intravenous sodium thiosulfate. Hydroxocobalamin is newly approved in the US and is available in Cyanokit antidote kits. Sulfanegen TEA, which could be delivered to the body through an intra-muscular (IM) injection, detoxifies cyanide and converts the cyanide into thiocyanate, a less toxic substance. Alternative methods of treating cyanide intoxication are used in other countries.
Following decontamination and the institution of supportive measures, the next priority is inhibition of further ethylene glycol metabolism using antidotes. The antidotes for ethylene glycol poisoning are ethanol and fomepizole. This antidotal treatment forms the mainstay of management of ethylene glycol poisoning. The toxicity of ethylene glycol comes from its metabolism to glycolic acid and oxalic acid. The goal of pharmacotherapy is to prevent the formation of these metabolites. Ethanol acts by competing with ethylene glycol for alcohol dehydrogenase, the first enzyme in the degradation pathway. Because ethanol has a much higher affinity for alcohol dehydrogenase, about a 100-times greater affinity, it successfully blocks the breakdown of ethylene glycol into glycolaldehyde, which prevents the further degradation. Without oxalic acid formation, the nephrotoxic effects can be avoided, but the ethylene glycol is still present in the body. It is eventually excreted in the urine, but supportive therapy for the CNS depression and metabolic acidosis will be required until the ethylene glycol concentrations fall below toxic limits. Pharmaceutical grade ethanol is usually given intravenously as a 5 or 10% solution in 5% dextrose, but it is also sometimes given orally in the form of a strong spirit such as whisky, vodka, or gin.
Fomepizole is a potent inhibitor of alcohol dehydrogenase; similar to ethanol, it acts to block the formation of the toxic metabolites. Fomepizole has been shown to be highly effective as an antidote for ethylene glycol poisoning. It is the only antidote approved by the U.S. Food and Drug Administration for the treatment of ethylene glycol poisoning. Both antidotes have advantages and disadvantages. Ethanol is readily available in most hospitals, is inexpensive, and can be administered orally as well as intravenously. Its adverse effects include intoxication, hypoglycemia in children, and possible liver toxicity. Patients receiving ethanol therapy also require frequent blood ethanol concentration measurements and dosage adjustments to maintain a therapeutic ethanol concentration. Patients therefore must be monitored in an intensive care unit. Alternatively, the adverse side effects of fomepizole are minimal and the approved dosing regimen maintains therapeutic concentrations without the need to monitor blood concentrations of the drug. The disadvantage of fomepizole is that it is expensive. Costing US$1,000 per gram, an average course used in an adult poisoning would cost approximately $3,500 to $4,000. Despite the cost, fomepizole is gradually replacing ethanol as the antidote of choice in ethylene glycol poisoning. Adjunct agents including thiamine and pyridoxine are often given, because they may help prevent the formation of oxalic acid. The use of these agents is based on theoretical observations and there is limited evidence to support their use in treatment; they may be of particular benefit in people who could be deficient in these vitamins such as malnourished or alcoholic patients.
Treatment of mild metal fume fever consists of bedrest, keeping the patient well hydrated, and symptomatic therapy (e.g. aspirin for headaches) as indicated. In the case of non-allergic acute lung injury, standard or recommended approaches to treatment have not been defined.
The consumption of large quantities of cow's milk, either before or immediately after exposure is a traditional remedy. However, the United Kingdom Health and Safety Executive challenges this advice, warning, "Don’t believe the stories about drinking milk before welding. It does not prevent you getting metal fume fever."
In addition to antidotes, an important treatment for poisoning is the use of hemodialysis. Hemodialysis is used to enhance the removal of unmetabolized ethylene glycol, as well as its metabolites from the body. It has been shown to be highly effective in the removal of ethylene glycol and its metabolites from the blood. Hemodialysis also has the added benefit of correcting other metabolic derangements or supporting deteriorating kidney function. Hemodialysis is usually indicated in patients with severe metabolic acidosis (blood pH less than 7.3), kidney failure, severe electrolyte imbalance, or if the patient's condition is deteriorating despite treatment. Often both antidotal treatment and hemodialysis are used together in the treatment of poisoning. Because hemodialysis will also remove the antidotes from the blood, doses of antidotes need to be increased to compensate. If hemodialysis is not available, then peritoneal dialysis also removes ethylene glycol, although less efficiently.
Dimercaprol and dimercaptosuccinic acid are chelating agents that sequester the arsenic away from blood proteins and are used in treating acute arsenic poisoning. The most important side effect is hypertension. Dimercaprol is considerably more toxic than succimer.
DMSA monoesters, e.g. MiADMSA, are promising antidotes for arsenic poisoning. Calcium sodium edetate is also used.
Supplemental potassium decreases the risk of experiencing a life-threatening heart rhythm problem from arsenic trioxide.
Current antidotes for OP poisoning consist of a pretreatment with carbamates to protect AChE from inhibition by OP compounds and post-exposure treatments with anti-cholinergic drugs. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime), though the use of "-oximes" has been found to be of no benefit, or possibly harmful, in at least two meta-analyses. Atropine is a muscarinic antagonist, and thus blocks the action of acetylcholine peripherally. These antidotes are effective at preventing lethality from OP poisoning, but current treatment lack the ability to prevent post-exposure incapacitation, performance deficits, or permanent brain damage. While the efficacy of atropine has been well-established, clinical experience with pralidoxime has led to widespread doubt about its efficacy in treatment of OP poisoning.
Enzyme bioscavengers are being developed as a pretreatment to sequester highly toxic OPs before they can reach their physiological targets and prevent the toxic effects from occurring. Significant advances with cholinesterases (ChEs), specifically human serum BChE (HuBChE) have been made. HuBChe can offer a broad range of protection for nerve agents including soman, sarin, tabun, and VX. HuBChE also possess a very long retention time in the human circulation system and because it is from a human source it will not produce any antagonistic immunological responses. HuBChE is currently being assessed for inclusion into the protective regimen against OP nerve agent poisoning. Currently there is potential for PON1 to be used to treat sarin exposure, but recombinant PON1 variants would need to first be generated to increase its catalytic efficiency.
One other agent that is being researched is the Class III anti-arrhythmic agents. Hyperkalemia of the tissue is one of the symptoms associated with OP poisoning. While the cellular processes leading to cardiac toxicity are not well understood, the potassium current channels are believed to be involved. Class III anti-arrhythmic agents block the potassium membrane currents in cardiac cells, which makes them a candidate for become a therapeutic of OP poisoning.
Prevention of metal fume fever in workers who are at risk (such as welders) involves avoidance of direct contact with potentially toxic fumes, improved engineering controls (exhaust ventilation systems), personal protective equipment (respirators), and education of workers regarding the features of the syndrome itself and proactive measures to prevent its development.
In some cases, the product's design may be changed so as to eliminate the use of risky metals. NiCd rechargeable batteries are being replaced by NiMH. These contain other toxic metals, such as chromium, vanadium and cerium. Cadmium is often replaced by other metals. Zinc or nickel plating can be used instead of cadmium plating, and brazing filler alloys now rarely contain cadmium.
Decontamination of people exposed to hydrogen cyanide gas only requires removal of the outer clothing and the washing of their hair. Those exposed to liquids or powders generally require full decontamination.
It is difficult to differentiate the effects of low level metal poisoning from the environment with other kinds of environmental harms, including nonmetal pollution. Generally, increased exposure to heavy metals in the environment increases risk of developing cancer.
Without a diagnosis of metal toxicity and outside of evidence-based medicine, but perhaps because of worry about metal toxicity, some people seek chelation therapy to treat autism, cardiovascular disease, Alzheimer's disease, or any sort of neurodegeneration. Chelation therapy does not improve outcomes for those diseases.
The management of AAlPP remains purely supportive because no specific antidote exists. Mortality rates approach 60%. Correction of metabolic acidosis is a cornerstone of treatment. The role of magnesium sulfate as a potential therapy in AlP poisoning may decrease the likelihood of a fatal outcome, and has been described in many studies. After ingestion, removal of unabsorbed poison from the gut ("gut decontamination"), especially if administered within 1–2 hours, can be effective. Potassium permanganate (1:10,000) gastric lavage can decompose the toxin. All patients of severe AlP poisoning require continuous invasive hemodynamic monitoring and early resuscitation with fluid and vasoactive agents.
Accidental poisonings can be avoided by proper labeling and storage of containers. When handling or applying pesticides, exposure can be significantly reduced by protecting certain parts of the body where the skin shows increased absorption, such as the scrotal region, underarms, face, scalp, and hands. Safety protocols to reduce exposure include the use of personal protective equipment, washing hands and exposed skin during as well as after work, changing clothes between work shifts, and having first aid trainings and protocols in place for workers.
Personal protective equipment for preventing pesticide exposure includes the use of a respirator, goggles, and protective clothing, which have all have been shown to reduce risk of developing pesticide-induced diseases when handling pesticides. A study found the risk of acute pesticide poisoning was reduced by 55% in farmers who adopted extra personal protective measures and were educated about both protective equiment and pesticide exposure risk. Exposure can be significantly reduced when handling or applying pesticides by protecting certain parts of the body where the skin shows increased absorption, such as the scrotal region, underarms, face, scalp, and hands. Using chemical-resistant gloves has been shown to reduce contamination by 33–86%.
The initial treatment of nicotine poisoning may include the administration of activated charcoal to try to reduce gastrointestinal absorption. Treatment is mainly supportive and further care can include control of seizures with the administration of a benzodiazepine, intravenous fluids for hypotension, and administration of atropine for bradycardia. Respiratory failure may necessitate respiratory support with rapid sequence induction and mechanical ventilation. Hemodialysis, hemoperfusion or other extracorporeal techniques do not remove nicotine from the blood and are therefore not useful in enhancing elimination. Acidifying the urine could theoretically enhance nicotine excretion, although this is not recommended as it may cause complications of metabolic acidosis.
There is no cure for berylliosis; the goals of treatment are to reduce symptoms and slow the progression of disease.
Although the evidence that stopping exposure to beryllium decreases progression of the disease, it is still considered to be an accepted approach to treatment in any stage of disease.
People with early stages of disease, without lung function abnormalities or clinical symptoms, are periodically monitored with physical exams, pulmonary function testing and radiography.
Once clinical symptoms or significant abnormalities in pulmonary function testing appear, treatments include oxygen and oral corticosteroids and whatever supportive therapy is required.
In adults, the initial treatment for paracetamol overdose is gastrointestinal decontamination. Paracetamol absorption from the gastrointestinal tract is complete within two hours under normal circumstances, so decontamination is most helpful if performed within this timeframe. Gastric lavage, better known as stomach pumping, may be considered if the amount ingested is potentially life-threatening and the procedure can be performed within 60 minutes of ingestion. Activated charcoal is the most common gastrointestinal decontamination procedure as it adsorbs paracetamol, reducing its gastrointestinal absorption. Administering activated charcoal also poses less risk of aspiration than gastric lavage.
It appears that the most benefit from activated charcoal is gained if it is given within 30 minutes to two hours of ingestion. Administering activated charcoal later than 2 hours can be considered in patients that may have delayed gastric emptying due to co-ingested drugs or following ingestion of sustained- or delayed-release paracetamol preparations. Activated charcoal should also be administered if co-ingested drugs warrant decontamination. There was reluctance to give activated charcoal in paracetamol overdose, because of the concern that it may also absorb the oral antidote acetylcysteine. Studies have shown that 39% less acetylcysteine is absorbed into the body when they are administered together. There are conflicting recommendations regarding whether to change the dosing of oral acetylcysteine after the administration of activated charcoal, and even whether the dosing of acetylcysteine needs to be altered at all. Intravenous acetylcystine has no interaction with activated charcoal.
Inducing vomiting with syrup of ipecac has no role in paracetamol overdose because the vomiting it induces delays the effective administration of activated charcoal and oral acetylcysteine. Liver injury is extremely rare after acute accidental ingestion in children under 6 years of age. Children with accidental exposures do not require gastrointestinal decontamination with either gastric lavage, activated charcoal, or syrup of ipecac.
Paracetamol ester prodrug with L-pyroglutamic acid (PCA), a biosynthetic precursor of glutathione, has been synthesized to reduce paracetamol hepatotoxicity and improve bioavailability. The toxicological studies of different paracetamol esters show that L-5-oxo-pyrrolidine-2-paracetamol carboxylate reduces toxicity after administration of an overdose of paracetamol to mice. The liver glutathione values in mice induced by intraperitoneal injection of the ester are superimposable with the GSH levels recorded in untreated mice control group. The mice group treated with an equivalent dose of paracetamol showed a significative decrease of glutathione of 35% (p<0.01 vs untreated control group). The oral LD50 was found to be greater than 2000 mg kg-1, whereas the intraperitoneal LD50 was 1900 mg kg-1. These results taken together with the good hydrolysis and bioavailability data show that this ester is a potential candidate as a prodrug of paracetamol.
Treatment is in the form of supportive care. If there is light-headedness, the victim should lie with feet partly elevated. If there is severe wheezing, then intramuscular epinephrine should be given, 0.5–1 ml at dilution of 1/1000 (standard medical emergency kit). An intravenous antihistamine like diphenhydramine should be given if needed.
Acute beryllium poisoning is an occupational disease. Relevant occupations are those where beryllium is mined, processed or converted into metal alloys, or where machining of metals containing beryllium or recycling of scrap alloys occurs.
Beryllium is regarded extraordinarily hazardous to health upon enough amounts of dust, mists, or fumes consisting fragments little enough to inhale (typically 10µm or less). Metallographic preparation equipment and laboratory work surfaces must be damp wiped occasionally to inhibit buildup of particles. Cutting, grinding, and polishing procedures which manufacture dusts or fumes must be handled within sufficiently vented coverings supplied with particular filters.
Hyperbaric oxygen is also used in the treatment of carbon monoxide poisoning, as it may hasten dissociation of CO from carboxyhemoglobin and cytochrome oxidase to a greater extent than normal oxygen. Hyperbaric oxygen at three times atmospheric pressure reduces the half life of carbon monoxide to 23 (~80/3 minutes) minutes, compared to 80 minutes for oxygen at regular atmospheric pressure. It may also enhance oxygen transport to the tissues by plasma, partially bypassing the normal transfer through hemoglobin. However, it is controversial whether hyperbaric oxygen actually offers any extra benefits over normal high flow oxygen, in terms of increased survival or improved long-term outcomes. There have been randomized controlled trials in which the two treatment options have been compared; of the six performed, four found hyperbaric oxygen improved outcome and two found no benefit for hyperbaric oxygen. Some of these trials have been criticized for apparent flaws in their implementation. A review of all the literature on carbon monoxide poisoning treatment concluded that the role of hyperbaric oxygen is unclear and the available evidence neither confirms nor denies a medically meaningful benefit. The authors suggested a large, well designed, externally audited, multicentre trial to compare normal oxygen with hyperbaric oxygen.