chelation Flashcards
BAL (british antilewiste), what is it and how does it work
dimercaprol. dithiol of a 2 adjacent sulfur groups which forms a ring structure upon electron pair donation and coordinate bonding to a metal. forms a stable chelate.
how do we use BAL
solubilized in peanut oil and injected.
what is BAL used to treat?
inorganic mercury and arsenic. also given with cana2EDTA in treatment for lead encephalopathy to prevent the redistribution of the lead to the brain.
what happens to BAL-chelate in acidic urine
it destabilizes decreasing urine excretion. urine alkalinization prevents thisl
what are the adverse effects of the BAL treatment
pain at injection, nausea, vomit, fever, fat emboli, lipoid pneumonia, chylothorax and hypoxia.
succimer
dimercaptosuccinic acid. is a dicarboxylic acid with 4 ionizable hydrogens. lead, arsenic, mercury, and cadmium all chelat.e
how do we give succimer
oral.
what does the succimer treat
lead, increases renal excretion.
what are the side effects of succimer
well tolerated, nausea, vomit, flatus, diarrhea, metallic taste, mild elevation of ALT/AST.
edetate calcium disodium
treatment of lead poisoning used together with BAL in severe lead encephalopathy. reverses the toxic effects of lead on the Hb.
how do we give edetate calcium
IM or IV where is remains in the blood.
what does it do to lead in the body
it mobilizes it from the tissues to the bone to the chelate. this is why we give BAL to block the redistribution to the brain.
what to watch out for when treating with edetate
nephrotoxicity
prussian blue
ferric hexacyanoferrate. thallium and radioactive cesium. hydrated crystal ferrous and ferric iron are coordinated ina cubic lattice chelation occurs through ion-exchange with iron and trapping in the lattice
how do we give prussian blue
orally and it is not absorbed through the gut. this prevents absorption, mobilizes body stores to the GI and then chelates it
