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Pharmacology II > Exam 3: Heavy Metal Toxicities > Flashcards

Exam 3: Heavy Metal Toxicities Flashcards

1
Q

Describe the 4 ways that metals can produce toxicity in humans

A
  1. Disrupt enzymatic and transport processes
  2. Loss of energy production
  3. Loss of ion regulation
  4. Potential carcinogenesis
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2
Q

Arsenic naturally occurs as what compound?

A
  • Arsenopyrite

- Most common arsenic containing material

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3
Q

What is the use for Arsenic?

A
  • Used therapeutically to kill amoebas and parasites (in developing countries)
  • Used for homicides and suicides
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4
Q

Local effect of Arsenic:

A

Dermatological

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5
Q

Name the systemic effects that Arsenic can have

A
  1. Vasodilation of capillaries
  2. GI effects (vomiting leads to fluid loss and CV collapse)
  3. CNS effects (peripheral neuropathies, organic encephalopathy)
  4. Headache
  5. Coma
  6. “Garlic Breath”
  7. Teratogenic
  8. Carcinogenic
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6
Q

How might one diagnose arsenic poisoning easily?

A
  • Garlic breath

Able to diagnose due to smell of breath

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7
Q

Describe the mechanism behind Arsenic causing vasodilation of capillaries

A

Arsenic binds to contractile mechanism so cannot contract

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8
Q

The vasodilation effect of Arsenic is evident in what symptoms

A
  • Rosy complexion
  • Edema
  • No wrinkles
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9
Q

What drug is used to treat Arsenic Poisoning

A
  • Dimercaprol

* *other names: BAL (British Anti-Lewisite); dithioglycerol

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10
Q

What is the mechanism of action for Dimercaprol

A

Sulfhydryl group combines with ions of various heavy metals to form relatively stable, nontoxic, soluble chelates which are excreted in urine

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11
Q

T or F, Antimony resembles a metal and reacts as such

A
  • False, It resembles a metal but does not react chemically as one.
  • Highly toxic
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12
Q

Antimony can be used pharmacologically how?

A

Used for treatment of protozoan infections

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13
Q

Explain the small doses vs large dose response when exposed to Antimony

A
  • Small: Headache, dizziness, depression

- Large: violent and frequent vomiting, diarrhea, muscle pain; death within a few days

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14
Q

What is the antidote to Antimony?

A

Dimercaprol

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15
Q

Describe Argyria and the symptoms associated with it

A
  • Definition: Silver and silver-containing compounds become absorbed into the circulatory system and deposited into body tissues
  • Symptoms
    ○ Bluish-grayish pigmentation of skin and mucous membranes
  • Permanent but not harmful
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16
Q

Argyria is often mistaken for what other toxicity?

A

Cyanosis

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17
Q

T or F, Argyria is permanent and can be harmful

A

False, Not harmful

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18
Q

Gold is used in what way pharmacologically

A
  • Used in dentistry
  • Used for treatment of rheumatoid arthritis
  • Enhances collagen cross-linking
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19
Q

T or F, Pure gold is not toxic

A

True

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20
Q

Can Gold salts be toxic?

A

Yes, toxic to the liver and kidneys

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21
Q

Name the symptoms of Gold toxicity

A
  1. Dermatitis
  2. Metallic taste in mouth
  3. Proteinuria
  4. GI symptoms
  5. Aplastic anemia
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22
Q

What is the antidote to Gold toxicity?

A
  • Dimercaprol

- penicillamine

23
Q

Mercury was used in the 1800’s to help infants in what?

A

It was in teething powders for infants and to treat toothaches

24
Q

What is Thiomersal

A
  • Preservative found in vaccines
  • It degrades to ethyl mercury
  • Many thought this was link to autism with vaccines. No evidence to support this
25
Q

Thiomersal has been removed from all vaccines or only in trace amounts for children under 6 years except one vaccine, what is the vaccine?

A

Inactivated influenza vaccine

26
Q

Mercury can still be found in what OTC medicines?

A
  • Topical antiseptics
  • Stimulant laxatives
  • Some dipaer rash ointments
  • Eye drops
  • Nasal sprays
27
Q

With continuing exposure to mercury, a fine tremor develops. Describe the initial tremor:

A

Tremor initially involves the hands and later spreads to the eyelids, lips and tongue.

28
Q

Effects experience from elemental mercury exposure:

A
  • Neurotoxicity with neuropsychiatric effects

- Acute poisoning = pneumonitis

29
Q

Effects of Inorganic mercury exposure:

A
  • Corrosive to oral cavity and gut

- Kidney damage

30
Q

What are the antidotes to mercury toxicity

A
  1. N-acetyl-D,L penicillamine
  2. Dimercaprol
  3. penicillamine
31
Q

What biochemical effect does lead poisoning have on the body

A
  • Enzyme inhibitor in the production of heme
    ○ Inhibits protoporphyrin IX
    Accumulation of aminolevulonic acid = diagnostic
32
Q

What symptoms and effects occur in individuals with lead poisoning?

A
  • Accumulates in CNS
  • GI, CV effects
  • Lead lines are visible in teeth in children
33
Q

What are the antidotes to lead poisoning

A
  • Combination: calcium EDTA and dimercaprol

* The combo is better than either alone

34
Q

What might be some effects on the body long-term exposure to lead

A
  • Nephropathy
  • Abdominal pain
  • Delayed puberty in girls
  • Reduced cognitive capacity
  • schizophrenia
35
Q

T or F, There is no evidence linking Cadmium to cancer

A

False, cadmium is known to cause cancer

36
Q

Cadmium poisoning is similar to what other heavy metal toxicity

A
  • Lead poisoning

- Inhibits same processes as lead

37
Q

Acute problems from cadmium poisoning

A

Pulmonary problems

38
Q

Chronic problems from cadmium poisoning

A
  • Emphysema, COPD

- Also goes into bones = reasonably non-toxic here

39
Q

Antidote to cadmium poisoning

A

Dimercaprol and calcium EDTA

40
Q

What is the risk of the antidote used to treat cadmium poisoning

A

Treatment mobilizes cadmium to the kidneys = possible renal toxicity

41
Q

What is the exposure to iron from?

A

From ferrous sulfate tablets used in the treatment of iron-deficiency anemia

42
Q

Name the symptoms of iron exposure

A
  • GI irritation
  • Pneumonitis
  • Convulsions
  • Coma
  • Liver damage
43
Q

Name the antidote to iron exposure

A

Deferoxamine

44
Q

Mechanism of Deferoxamine

A
  • Complexes with trivalent ions (Ferric ions) to form ferrioxamine, which is removed by the kidneys
45
Q

Symptoms to Aluminum exposure

A
  • Pots and pans senility
  • Concern for assoc. with Alzheimer’s disease
  • End stage renal failure
46
Q

Antidote for aluminum exposure

A
  • Deferoxamine

- Aluminum chelating agents are given to reduce amount

47
Q

How might one get nickel exposure:

A

Exposure from electronic, steel and mining industries

48
Q

Symptoms of nickel exposure

A
  • Dermatitis

- Nasal and respiratory cancer

49
Q

Antidote for nickel exposure:

A

Diethylthiocarbamate trihydrate

50
Q

Requirements for Heavy Metal Antagonists used as antidotes

A
  1. Water solubility
  2. Resistant to metabolic degradation
  3. Small size (so excreted by kidney)
  4. Chelate is stable at physiological pH
  5. Chelate is less toxic than the ion
  6. Bind the toxic metal better than it binds Ca+
    • *If not, risk for calcium deficiency
51
Q

Dimercaprol is an antidote used in what toxicities?

A
  • Arsenic
  • Antimony
  • Gold
  • Mercury
52
Q

Calcium disodium edelate (EDTA) is an antidote used in what toxicities?

A
  • Lead

- Cadmium

53
Q

Penicillamine has what function and is used as an antidote to what toxicities?

A
  • Used long term to clear bone, skin and keratinized tissues of arsenic, antimony
  • Gold
  • Mercury
54
Q

Deferoxamine is an antidote used for what toxicities?

A
  • Iron

- Aluminum

Pharmacology II (24 decks)

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