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MT 6314 2nd Shift > 6.2: Heavy Metals And Chelators > Flashcards

6.2: Heavy Metals And Chelators Flashcards

1
Q

Heavy Metals

A

• Lead
• Arsenic
• Mercury

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2
Q

What are the 9 Chelator/Chelating Agent?

A
  • Dimercaprol
  • Succimer
  • Edetate Calcium Disodium
  • Unithiol
  • Penicillamine
  • Deferoxamine
  • Deferasirox and Deferiprone
  • Prussian Blue
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3
Q

• Storage batteries, ammunition,
• metal alloys, solder, glass,
• plastics, pigments and
• ceramics
• No useful purpose in the human body

A

Lead

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4
Q

Absorbed slowly but consistently via respiratory and gastrointestinal tract

A

Pharmacokinetics

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5
Q

Identify the heavy metal based on its pharmacokinetics:

Low dietary calcium, iron deficiency and ingestion on an empty stomach increases absorption

A

Lead

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6
Q

Identify the heavy metal based on its pharmacokinetics:

Poor absorption in the skin

A

Lead

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7
Q

Up to what % absorbed in children in lead

A

50%

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8
Q

Up to what % in adults is absorbed in lead?

A

10-15%

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9
Q

Lead (pharmacokinetics):

What exposure is seen in respiratory tract?

A

industrial exposure

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10
Q

Lead (pharmacokinetics):

What exposure is seen in intestinal tract?

A

nonindustrial exposure

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11
Q

Lead [pharmacokinetics]

What % bound to RBCs, what % free in plasma

A

99% : 1%

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12
Q

Identify the heavy metal based on its pharmacokinetics:

Distributed to bone marrow, brain, kidney, liver, muscle and gonads; then bones

A

Lead

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13
Q

Identify the heavy metal based on its pharmacokinetics:

Crosses the placenta

A

Lead

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14
Q

What is the half-life of Lead?

A

1-2 mos

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15
Q

What is the half-life of Lead in bones?

A

years to decades

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16
Q

Lead [pharmacokinetics]

What % excreted in the urine

A

70%

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17
Q

Identify the heavy metal based on its pharmacodynamics:

  • Multiple mechanisms of action
  • Inhibition of enzymatic function
  • Interference with action of essential cations (calcium, zinc, iron)
  • Oxidative stress generation
  • Gene expression changes
  • Cell signaling alteration
  • Disruption of membrane integrity
A

Lead

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18
Q

Major Forms of Lead Intoxication

A
  • Inorganic Lead Poisoning
  • Organolead Poisoning
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19
Q

What is the treatment for Lead?

A

Immediate termination of exposure, supportive care and rational use of chelation therapy

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20
Q

Identify the heavy metal based on its treatment:

Retained lead objects require gastrointestinal decontamination

A

Lead

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21
Q

Lead [Treatment]

Intravenous edetate calcium disodium (CaNa2EDTA) at a dosage of ___ mg/kg/d by continuous infusion for up to __ days only

A

30-50 mg/kg/d : 5

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22
Q

Treatment for Lead:

Oral Succimer (DMSA) after __ days

A

5

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23
Q

Identify this heavy metal:

Semiconductors, wood preservatives, nonferrous alloys, glass and turf herbicide monosodium methane arsonate (MSMA)

A

Arsenic

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24
Q

Groundwater may contain high amounts of arsenic

A

Arsenic

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25
Q

Identify this heavy metal:

Historically, used as a pharmaceutical agent but now limited in use

A

Arsenic

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26
Q

Identify the heavy metal based on its pharmacokinetics:

Well-absorbed via respiratory and GI tract

A

Arsenic

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27
Q

True or False:

In the pharmacokinetics of Arsenic, percutaneous absorption is limited.

A

True

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28
Q

In the pharmacokinetic of Arsenic, it is metabolized by the liver via?

A

methylation reactions

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29
Q

Arsenic [Pharmacokinetics] is excreted in the?

A

Urine (major), sweat and feces

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30
Q

Identify the heavy metal based on its pharmacodynamics:

Multiple mechanism of actions:
* Inhibition of enzyme functions
* Oxidative stress generation
* Gene expression changes
* Cell signaling alteration

A

Arsenic

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31
Q

Identify this heavy metal:

  • Hyperpigmentation and hyperkeratosis involving hands and feet
  • Chronic inorganic arsenic poisoning
A

Raindrop pattern

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32
Q

• Immediate termination of exposure, supportive care and chelation therapy
• Gut decontamination if appropriate

A

Arsenic [Treatment]

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33
Q

Arsenic [Treatment]

Acute Poisoning: Chelation with Unithiol __mg/kg every __ hours or Dimercaprol every __ hours

A

3-5mg/kg : 4-6 hours

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34
Q

Quicksilver or liquid metal

A

Mercury

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35
Q

Mined predominantly as HgS in cinnabar ores

A

Mercury

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36
Q

Electrolytic production of chlorine and caustic soda; electrical equipment, thermometer, instruments, fluorescent lamps; dental amalgams; artisanal gold production

A

Mercury

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37
Q

True or False:

Thimerosal, an organomercurial preservative, are kept in almost all vaccines in mercury.

A

False

They are removed from almost all vaccines.

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38
Q

Environmental release of mercury from burning of fossil fuels contributes to bioaccumulation in fishes

A

Mercury

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39
Q

Absorption varies depending on chemical form

A

Mercury [Pharmacokinetics]

40
Q

Mercury [Pharmacokinetics]

Absorbed from the??

A

Lungs, GI tract, and percutaneous route

41
Q

In the pharmacokinetics of Mercury, it is well-distributed into tissues and most concentrated in __?

A

Kidneys

42
Q

Mercury [Pharmacokinetics]

Excreted via?

A

urine and feces

43
Q

immediate removal from source, supportive care and chelation therapy

A

Mercury [Treatment]

44
Q

Mercury [Treatment]

Acute

A

Unithiol, dimercaprol or succimer

45
Q

True or False.

Dimecaprol should never be used for elemental or organic mercury intoxication.

A

True

46
Q

Pharmacology of Chelators

A

Metallic ion + chelating agent —> metallic chelate

47
Q

Drugs used to prevent or reverse the toxic effects of heavy metals on an enzyme or other cellular target, or to accelerate the elimination of metal from the body

A

Chelators or Chelating Agents

48
Q

The metal-mobilizing effects of a therapeutic chelating agent may also redistribute some of the metal to vital organs

A

Chelators or Chelating Agents

49
Q

They may also enhance excretion of essential cations (Zinc, Copper)

A

Chelators or Chelating Agents

50
Q

True or False:

The longer the half-life of a metal in a particular organ, the more effectively they can be removed by chelation.

A

False

It will be less effective.

51
Q

What are the chelators or chelating agents?

A
  • Dimercaprol
  • Succimer
  • Edetate Calcium Disodium (EDTA)
  • Unithiol
  • Penicillamine
  • Deferoxamine
  • Deferasirox
  • Deferiprone
  • Prussian Blue
52
Q

What is the antidote to a warfare agent of Dimercaprol?

A

Lewesite

53
Q

Adverse effects: hypertension, tachycardia, nausea, vomiting, lacrimation, salivation, fever, pain at injection site, thrombocytopenia, increase Prothrombin time

A

Dimercaprol
[ 2,3-Dimercaptopropanolol, BAL]

54
Q

Dimercaprol [ 2,3-Dimercaptopropanolol, BAL]

As single-agent: arsenic and inorganic mercury

A

acute poisoning

55
Q

Dimercaprol [ 2,3-Dimercaptopropanolol, BAL]

As conjunction with EDTA

A

severe lead poisoning

56
Q

[ T or F ]

Dimercaprol [ 2,3-Dimercaptopropanolol, BAL]

It prevents and reverses metal-induced inhibition ofsulfhydryl-containing enzyme

A

True

57
Q

Dimercaprol [ 2,3-Dimercaptopropanolol, BAL]

Increases rate of excretion of ?

A

arsenic and lead

58
Q

Dimercaprol [ 2,3-Dimercaptopropanolol, BAL]

Is given via __, excreted via __

A

IM : kidneys

59
Q

Redistributes arsenic and mercury to CNS

A

Dimercaprol [ 2,3-Dimercaptopropanolol, BAL]

60
Q

Identify this chelating agent:

Water-soluble analog of dimercaprol

A

Succimer

Dimercaptosuccinic Acid, DMSA

61
Q

It prevents and reverses metal-induced inhibition of sulfhydryl-containing enzyme

A

Succimer [Dimercaptosuccinic Acid, DMSA]

62
Q

Succimer [Dimercaptosuccinic Acid, DMSA]

Treatment of children with blood lead concentration of?

A

> 45mcg/dL

63
Q

Identify this chelating agent:

  • Increase rate of excretion of lead
  • It decreases mercury content in kidney
A

Succimer

Dimercaptosuccinic Acid, DMSA

64
Q

Identify this chelating agent:

Has protective effect against arsenic as well

A

Succimer

Dimercaptosuccinic Acid, DMSA

65
Q

Succimer (Dimercaptosuccinic Acid, DMSA)
is given in what route?

A

Oral, IV

66
Q

Succimer [Dimercaptosuccinic Acid, DMSA]

Adverse effects

A

GI disturbances are the most common

67
Q

Succimer [Dimercaptosuccinic Acid, DMSA]

Associated with increase in?

A

ALT, AST, mild neutropenia

68
Q

Calcium disodium salt form of EDTA

A

Edetate Calcium Disodium
[Ethylenediaminetetraacetic Acid, EDTA]

69
Q

Indicated mainly for chelation of lead

A

Edetate Calcium Disodium
[Ethylenediaminetetraacetic Acid, EDTA]

70
Q

Identify this chelating agent:

Chelator of zinc, manganese and certain heavy radionucleotide poisoning

A

Edetate Calcium Disodium

Ethylenediaminetetraacetic Acid, EDTA

71
Q

Identify the chelating agents:

Chelates extracellular metals ions much more effectively compared to intracellular metal ions

A

Edetate Calcium Disodium

Ethylenediaminetetraacetic Acid, EDTA

72
Q

[T or F ]

Edetate Calcium Disodium [Ethylenediaminetetraacetic Acid, EDTA]

Limited oral absorption

A

True

73
Q

Edetate Calcium Disodium [Ethylenediaminetetraacetic Acid, EDTA]

Given __; Excreted via the __

A

IV infusion : kidney

74
Q

Water-soluble analog of dimercaprol

A

Unithiol [Dimercaptopropanesulfonic Acid, DMPS]

75
Q

Identify this chelating agent:

Protective effects against mercury and arsenic

A

Unithiol

Dimercaptopropanesulfonic Acid, DMPS

76
Q

[ T or F ]

Unithiol has FDA approved indications.

A

FALSE

Wala!!!!

77
Q

True or False:

In Unithiol, it decreases urinary excretion of mercury, arsenic and lead.

A

False

Increases.

78
Q

True or False:

Unithiol [Dimercaptopropanesulfonic Acid, DMPS]
* Given Orally and IV (slow infusion)
* Excreted via kidneys

A

True

79
Q

What are the adverse effects of Unithiol?

A
  • Dermatologic reactions
  • Urticaria
  • Exanthems; isolated cases of SJS
  • Erythema multiforme
80
Q

Identify this chelating agent:

White, crystalline, derivative of Penicillin

A

Penicillamine

D-Dimethylcysteine

81
Q

Identify this chelating agent:

Also used in Severe Rheumatoid Arthritis

A

Penicillamine

D-Dimethylcysteine

82
Q

Identify the chelating agent:

Used primarily to treat or prevent Copper poisoning (i.e. Wilson’s Disease)

A

Penicillamine

D-Dimethylcysteine

83
Q

[ T or F ]

Penicillamine [D-Dimethylcysteine]

L-isomer form is less toxic than the D-Penicillamine

A

False. Should be D-Penicillamine is less toxic than the L-isomer form

84
Q

Penicillamine [D-Dimethylcysteine]

Adverse effects:

A

Hypersensitivity, nephrotoxicity with proteinuria, pancytopenia, pyridoxine insufficiency

85
Q

[ T or F ]

Penicillamine [D-Dimethylcysteine]

Absorbed via oral route

A

True

86
Q

Isolated from Streptomyces pilosus

A

Deferoxamine

87
Q

Identify what chelating agent:

The parenteral chelator of choice for iron poisoning.

A

Deferoxamine

88
Q

Identify this chelating agent:

This chelating agent is useful in treatment of aluminum toxicity with hemodialysis.

A

Deferoxamine

89
Q

What is the adverse effects of Deferoxamine?

A
  • Hypotension
  • Flushing
  • Abdominal discomfort
  • Rashes
  • Pulmonary complications
90
Q

[Deferoxamine]

Excreted in the __

A

Urine

91
Q

The given route of Deferoxamine is through:

A

IM or IV

92
Q

Identify this chelating agent:

Indicated for treatment of contamination with radioactive Cesium and intoxication with thallium salts

A

Prussian Blue

Ferric Hexacyanoferrate

93
Q

Identify this chelating agent:

Ion exchange and mechanical trapping or adsorption

A

Prussian Blue

Ferric Hexacyanoferrate

94
Q

Prussian Blue [Ferric Hexacyanoferrate]

Adverse effects:

A

Constipation

95
Q

[ T or F ]

Prussian Blue [Ferric Hexacyanoferrate]

Given orally, minimal GI absorption (<2%), excreted via feces

A

False. (<1%)

MT 6314 2nd Shift (8 decks)

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