As previously discussed, 2,3-dimercaptosuccinic acid (DMSA) and N -acetyl-D,L-penicillamine have been used as chelating agents in the treatment of mercury toxicity. Use chelating agents if the patient is symptomatic, systemic absorption is anticipated, or increased blood or urine levels are present. Chelating agents should be administered early in treatment.
GI decontamination may be useful only in acute, recent ingestions. Activated charcoal is indicated for GI decontamination because it binds inorganic and organic mercury compounds to some extent.
These agents are used to help remove a portion of the body's mercury stores. They are administered early in treatment because mercury binds to the body's ubiquitous sulfhydryl groups. Chelating agents are thought to use their thiol groups to compete with sulfhydryl groups in binding methyl mercury. The effectiveness of chelation in preventing or treating neurologic toxicity has not been well evaluated.
DMSA is used in inorganic and organic mercurials. It is considered superior to penicillamine because it has fewer adverse effects. Because of this agent's ease of use, good efficacy, and safety, initiate treatment with DMSA if good evidence indicates that significant absorption can occur (mercury levels may not be readily available). DMSA is the chelator of choice in cases of chronic or mild toxicity.
This is the drug of choice for the treatment of acute inorganic mercury toxicity. It is the preferred chelator for mercury salts. Dimercaprol is administered intramuscularly every 4 hours, mixed in a peanut oil base. It is excreted in urine and bile. Dimercaprol may be given to patients with renal failure. The BAL-mercury complex is dialyzable. Dimercaprol is used only in acute ingestion.
D-penicillamine is an oral, thiol-based chelator for acute or chronic toxicity. It is less well tolerated than DMSA (succimer). D-penicillamine forms a complex with mercury and is excreted in urine; therefore, do not use it in renal failure. This agent cannot be considered a first-line drug, because DMSA is safer and more effective.
These agents are empirically used to minimize systemic absorption of the toxin. They may be of benefit only if they are administered within 1-2 hours of ingestion.
Activated charcoal has a network of pores that adsorbs 100-1000mg of drug per gram of charcoal. It does not dissolve in water.
This is a laxative with strong electrolyte and osmotic effects that has cathartic actions in the GI tract.
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