Chelator pharmacology FINAL test

Question 1

How do chelators work on heavy metals?

Answer 1

-Render heavy metal ions unavailable for covalent interactions

Question 2

How does the half life of the heavy metal affect the ability of a chelator to remove it from a target organ?

Answer 2

-The longer the 1/2 life the less effective is the chelator

Question 3

Is it better to treat with chelators quickly or take a wait and see approach when exposure has occurred?

Answer 3

-Usually most effective when treated ASAP

Question 4

What are four chelators?

Answer 4

• Dimercaprol
• Unithiol
• Succimer
• Edetate calcium disodium

Question 5

Dimercaprol is FDA approved for which heavy metal poisonings as a monotherapy?

Answer 5

• Acute arsenic

- Acute Mercury

Question 6

Dimercaprol can be administered with edetate calcium disodium to treat chronic poisoning with what heavy metal?

Answer 6

-Severe lead poisoning

Question 7

Why should dimercaprol no be given as a monotherapy after chronic exposure to lead?

Answer 7

-It pulls Pb from bone and it goes to brain and causes toxicity?

Question 8

Is dimercaprol water soluble?

Answer 8

-No

Question 9

What is the only route of administration of dimercaprol?

Answer 9

-IM route only

Question 10

How does the therapeutic index of dimercaprol compare to succimer or unithiol?

Answer 10

-It can be very toxic, especially on kidneys

Question 11

T/F Succimer has for the most part eplaced dimercaprol

Answer 11

True

Question 12

Unithiol is a water soluble derivative of what other chelator?

Answer 12

-Dimercaprol

Question 13

What are the routes of administration of unithiol?

Answer 13

• Orally

- IV

Question 14

How does the half life of unithiol’s compare to the other chelators?

Answer 14

-20 hours, which is much longer than other chelators

Question 15

What heavy metal poisonings is unithiol FDA approved to treat?

Answer 15

-None

Question 16

What heavy metal poisoning is unithiol effective against?

Answer 16

• Mercury
• Arsenic
• Lead
• it is effective against these, just not FDA approved to treat

Question 17

What is the water soluble form of dimercapro?

Answer 17

• Succimer

- Also unithiol

Question 18

What heavy metal poisonings is Succimer FDA approved for?

Answer 18

• Treat Lead
• Arsenic
• Mercury

Question 19

What is the main mechanism of succimer for removing heavy metals?

Answer 19

-Binds to cysteine to form mixed disulfides which are excreted

Question 20

What is the half life of succimer?

Answer 20

2-4 hrs

Question 21

What is the only route of administration of succimer?

Answer 21

-Oral use only

Question 22

What is safer, Dimercaprol or succimer?

Answer 22

-Succimer, which is why it is preferred over dimercaprol

Question 23

What heavy metal poisoning is Edetate calcium disodium FDA approved for?

Answer 23

-Lead poisoning

Question 24

Does Edetate calcium disodium target intracellular or extracellular lead?

Answer 24

-Only extracellular

Question 25

What is the only route of administration for Edetate calcium disodium?

Answer 25

-IV

Question 26

What is the half life of Edetate Calcium disodium?

Answer 26

-1 hour

Question 27

How is edetate calcium disodium excreted?

Answer 27

-100% by the kidneys

Question 28

In what patient population is edetate calcium disodium contraindicated in?

Answer 28

-Anuric patients because it is excreted by the kidneys (can't be cleared because anuric patients don't produce urine)

Question 29

What are the four criteria for dental material biocompatibilty?

Answer 29

- Should not be harmful to pulp or soft tissues - Should not contain toxic diffusible substances that may be released and absorbed into the circulatory system to cause systemic toxicity - Should be free of potentially sensitizing agents that may promote reactions - Should have NO carcinogenic potential

Question 30

What step in amalgam fillings results in the greatest release of mercury?

Answer 30

-Dry polishing of an amalgam filling

Question 31

How can a dentist prevent lesions caused by zinc phosphate cement?

Answer 31

-Use proper mix or use a resin modified GI cement instead

Question 32

How can a dentist reduce the cytotoxicity of acrylate bonding agents?

Answer 32

-Adequately rinse with tap water between applications of subsequent reagents

Question 33

What is Anthracosis?

Answer 33

-Inhalation of carbon dust resulting in chronic dry cough

Question 34

what are the common allergic reactions observed in dental practices?

Answer 34

- allergic contact dermatitis - latex allergies - allergies to denture-based materials

Question 35

what steps can be taken to prevent pulpitis caused by unpolymerized monomers in resin composites used in deep fillings?

Answer 35

-use twice the recommended time of exposure and cure in increments to assure complete curing

Question 36

why is adequate ventilation and use of exhaust fans essential if working with metals in the laboratory?

Answer 36

-because dust/vapors from these materials can to exposure and toxicity

Question 37

___ is described as materials that elicit an appropriate biological response, without toxic or adverse immunological response, when exposed to the body or bodily fluids

Answer 37

-biocompatibility

Question 38

dimercaptopropanesulfonic acid is also known as ___

Answer 38

-unithiol

Question 39

CaNa2-EDTA is also known as ___

Answer 39

-edetate calcium disodium

Question 40

dimercaprol can be administered with edetate calcium disodium to treat severe, chronic poisoning of what heavy metal?

Answer 40

-lead