Effective oral chelation on the toxicity of mercury and other heavy metal poisoning is now available with DMSA (meso-2, 3-dimercaptosuccinic acid) and DMPS (2, 3-dimercapto propane-1-sulfonic acid). These oral chelators are water soluble and can take the form of tablets. Sulf-hydryl structures are present in their structure is responsible for the property chelation. These structures bind mercury in the body, leading to its selection.

Oral chelators were obtained from dimercaprol, also known as British anti-lewisite (BAL). BAL was used in chelation therapy for heavy metal poisoning from the 1940's. In 1975, showed that Friedheim DMSA been a better choice than BAL chelation therapy for mercury. These oral chelators also have a mild toxicity profile compared with BAL and D-penicillamine. Since then, DMSA was the first choice for oral chelation for mercury poisoning.

In the acute toxicity of mercury, DMSA is given at a dose of 10 mg per kilogram of body weight divided into three times a day for five days. For example, 60 kg person will be required DMSA 200 mg three times daily for 5 days. Then the frequency of administration reduced to twice a day for the next fourteen days. After oral chelation is guided by the blood and 24-hour urine levels of mercury. Chelation should be continued until the level of mercury in blood and 24-daily urine mercury falls below 20 micrograms per liter.

Ease of administration: Oral chelators are taken in pill form, while the BAL should be given a painful injection in the muscle. Oral chelators are especially useful in the chronic toxicity of mercury (except for acute toxicity), which requires long-term therapy Enterosorbents.

Oral chelators are stable at room temperature for a long time. They retain their chemical structure and function, despite the impact on the environment while BAL is unstable and very susceptible to oxidation.

Chelation therapy with oral chelators like DMSA has no toxic effects on the brain. Some injectable chelators, BAL, such as reallocation of organic mercury from the system in the brain and can impair nerve function in organic mercury toxicity. On the other hand, as the oral chelator DMSA removes mercury from the brain. Studies on animals have also emphasized that the oral chelation with DMSA is the most effective chelation therapy, the decrease in mercury concentration up to 66,6% of the brain in an organic mercury toxicity.

High safety margin: the dose required for toxicology testing with oral chelators is very high compared with the dose required for therapy. The room for error can be used in oral chelation security without close supervision by a physician. On the other hand, BAL chelation therapy should be monitored very strictly.

safety and efficacy of oral chelators have been shown in numerous studies on animals and humans. DMSA treatment results in the highest excretion of mercury compared to other chelators of heavy metals. DMSA is highly effective in removing mercury from the blood, liver, brain, spleen, lung, colon, skeletal muscle and bone.

Oral chelators typically do not produce any serious side effects than other stomach upsets, and skin rash. Rarely chelation therapy may lead to a reduction in blood cells and increase in liver enzymes. Nevertheless, they can lead to a shortage of copper, zinc, manganese and molybdenum. These minerals must be supplemented when it is prescribed oral chelation. Oral chelator, DMPS may cause asthma attacks and lower blood pressure in some patients. Oral chelators remove mercury excretion in the urine. Therefore, they can be used only in people with normal kidney function.