Chelation Flashcards
Forms stable chelate via electron pair donation and coordination with metal ion
British Anti-Lewisite–Dimercaprol
Solubilizied in peanut oil
British Anti-Lewisite–Dimercaprol
Risk of allergic rxn if allergic to peanuts
What are the uses for Dimercaprol–BAL
Arsenic, lead, inorganic mercury poisoning
What must be done when giving dimercaprol–BAL in order to prevent renal toxicity?
Urine alkalinization
Coordinate bonding to sulfur (arsenic and mercury) or sulfur and oxygen (lead and cadmium)
2,3 dimercaptosuccinic acid–Succimer
What are the uses for 2,3 dimercaptosuccinic acid–Succimer
Arsenic, lead, mercury, cadmium poisoning
What may be elevated with the use of 2,3 dimercaptosuccinic acid–Succimer?
ALT/AST
Displacement of Ca++ by lead
Edetate calcium disodium (EDTA)
What is Edentate calcium disodium (EDTA) used for?
Lead poisoning
What are the side effects of edentate calcium disodium (EDTA)?
Renal toxicity–proximal tubules, distal tubules, glomeruli
ALT/AST increase
What is Na2EDTA and what can it cause?
Can be confused for EDTA and can cause major hypocalcemia
What can occur is Edentate calcium disodium (EDTA) is given in lead encephalopathy and what is done to prevent this?
Potential to cause lead redistrivution into the brain
BAL must be given before this–to prevent this
Stays in gut and not absorbed until it grabs metal–goes into gut and is excreted that way?
Ferric hyacyanoferrate/Prussian blue
What is Ferric hyacyanoferrate/Prussian blue used for?
Thallium and radioactive cesium poisoning
Chelates free iron and iron transported btw transferrin and ferritin?
Deferoxamine
What is Deferoxamine used for?
Acute iron poisoning and chronic iron overload
What is the major side effect of Deferoxamine that only allows for tx duration of 24hrs
Can only treat for 24 hrs before acute lung injury manifests
Where is Deferoxamine derived from?
Streptomyces pilosus
What is the mechanism of action of Deferoxamine?
Chelates ferric iron and is excreted in the urine as ferrioxamine which imparts a reddish brown color change to the urine
What is NOT chelated by Deferoxamine?
Transferrin
Hb
Cytochromes
Ferritin
How do heavy metals cause toxicity?
By binding to sulfhydryl groups–multi-organ dysfunction
What makes prussian blue unique?
It does NOT get absorbed after oral administration
What are the hallmarks of lead poisoning in children?
Colic Basophilic stippling Burtons lines--> gums Lower levels associated with IQ changes Think PICA
What are the hallmarks of lead poisoning in adults?
HTN
Basophilic stippling
Burtons lines–> gums
Tolerate higher lead levels
