Chelation

Question 1

Forms stable chelate via electron pair donation and coordination with metal ion

Answer 1

British Anti-Lewisite–Dimercaprol

Question 2

Solubilizied in peanut oil

Answer 2

British Anti-Lewisite–Dimercaprol

Risk of allergic rxn if allergic to peanuts

Question 3

What are the uses for Dimercaprol–BAL

Answer 3

Arsenic, lead, inorganic mercury poisoning

Question 4

What must be done when giving dimercaprol–BAL in order to prevent renal toxicity?

Answer 4

Urine alkalinization

Question 5

Coordinate bonding to sulfur (arsenic and mercury) or sulfur and oxygen (lead and cadmium)

Answer 5

2,3 dimercaptosuccinic acid–Succimer

Question 6

What are the uses for 2,3 dimercaptosuccinic acid–Succimer

Answer 6

Arsenic, lead, mercury, cadmium poisoning

Question 7

What may be elevated with the use of 2,3 dimercaptosuccinic acid–Succimer?

Answer 7

ALT/AST

Question 8

Displacement of Ca++ by lead

Answer 8

Edetate calcium disodium (EDTA)

Question 9

What is Edentate calcium disodium (EDTA) used for?

Answer 9

Lead poisoning

Question 10

What are the side effects of edentate calcium disodium (EDTA)?

Answer 10

Renal toxicity–proximal tubules, distal tubules, glomeruli

ALT/AST increase

Question 11

What is Na2EDTA and what can it cause?

Answer 11

Can be confused for EDTA and can cause major hypocalcemia

Question 12

What can occur is Edentate calcium disodium (EDTA) is given in lead encephalopathy and what is done to prevent this?

Answer 12

Potential to cause lead redistrivution into the brain

BAL must be given before this–to prevent this

Question 13

Stays in gut and not absorbed until it grabs metal–goes into gut and is excreted that way?

Answer 13

Ferric hyacyanoferrate/Prussian blue

Question 14

What is Ferric hyacyanoferrate/Prussian blue used for?

Answer 14

Thallium and radioactive cesium poisoning

Question 15

Chelates free iron and iron transported btw transferrin and ferritin?

Answer 15

Deferoxamine

Question 16

What is Deferoxamine used for?

Answer 16

Acute iron poisoning and chronic iron overload

Question 17

What is the major side effect of Deferoxamine that only allows for tx duration of 24hrs

Answer 17

Can only treat for 24 hrs before acute lung injury manifests

Question 18

Where is Deferoxamine derived from?

Answer 18

Streptomyces pilosus

Question 19

What is the mechanism of action of Deferoxamine?

Answer 19

Chelates ferric iron and is excreted in the urine as ferrioxamine which imparts a reddish brown color change to the urine

Question 20

What is NOT chelated by Deferoxamine?

Answer 20

Transferrin
Hb
Cytochromes
Ferritin

Question 21

How do heavy metals cause toxicity?

Answer 21

By binding to sulfhydryl groups–multi-organ dysfunction

Question 22

What makes prussian blue unique?

Answer 22

It does NOT get absorbed after oral administration

Question 23

What are the hallmarks of lead poisoning in children?

Answer 23

Colic
Basophilic stippling
Burtons lines--> gums
Lower levels associated with IQ changes
Think PICA

Question 24

What are the hallmarks of lead poisoning in adults?

Answer 24

HTN
Basophilic stippling
Burtons lines–> gums
Tolerate higher lead levels

Question 25

What are the hallmarks of arsenic poisoning?

Answer 25

Rice water diarrhea
Prolonged QTc
Arsenical dermatitis
Rain drops on a dusty road

Question 26

What are the hallmarks of mercury poisoning?

Answer 26

Labile Mood–mad as a hatter
Intention tremor
Mercury salt–caustic

Question 27

What are the hallmarks of Thallium poisoning?

Answer 27

Painful neuropathy

Alopecia