Heavy Metals + Antagonists

Question 1

For lead, describe route of absorption

Answer 1

Absorption routes = lungs, GI tract

From lungs, most lead binds to hemoglobin in RBCs before distribution to liver, kidneys

With time, most ends up in bone

Question 2

For lead, describe targeted organs

Answer 2

Brain

Liver

Kidneys

Question 3

For lead, describe major signs of toxicity

Answer 3

GI: cramping, diarrhea, constipation

Neuromuscular: muscle weakness

CNS: lead encephalopathy = vertigo, headache, irritability

Blood: anemia

Kidneys: lead nephropathy, hyperuricemia, gout, HTN

ashen color to face

Stooped posture

“Lead line” of lead deposition to gums

Question 4

For mercury, describe major route of absorption

Answer 4

Elemental mercury: absorbed completely in lungs

Mercury inorganic salts:
Absorbed in GI with highest accumulation in kidneys - don’t pass BBB or placenta

Organic mercurials:
Readily absorbed in GI tract

Question 5

For mercury, describe targeted organs

Answer 5

Methylmercury = liver, kidney

Passage through BBB involves conjugation

Question 6

For mercury, describe major signs of toxicity

Answer 6

Elemental:
Weakness, chills, metallic taste, N, cough

Salts: ashen gray mucosa of mouth, renal toxicity, “pink disease” with pink discoloration

Organic mercurials:
Ataxia, hearing loss, tremor, mental retardation

Question 7

For arsenic, describe major route of absorption

Answer 7

Absorbed in GI tract

Stored in liver, kidneys, heart, lungs

Deposited in hair, nails, bone, teeth

Question 8

For arsenic, describe targeted organs

Answer 8

SKIN!!!!

Liver

Kidney

Heart

Lungs

Question 9

For arsenic, describe major signs of toxicity and the diagnosis

Answer 9

CV: hypotension, CHF, gangrene
GI: cramping, diarrhea
Skin: hyperpigmentation, vasodilation, cancer

CNS: peripheral neuropathy
Blood: anemia
Liver: necrosis

Poisoning is rare due to federal regulations

Question 10

For cadmium, describe major route of absorption

Answer 10

Mostly through lungs from cigarette smoke

Poor absorption in GI

Question 11

For cadmium, describe targeted organs

Answer 11

Kidneys

Liver

Question 12

For cadmium, describe major signs of toxicity and the diagnosis

Answer 12

Kidneys: proteinuria, dec. filtration = irreversible damage!

Lungs: poor ventilators capacity, labored breathing, emphysema

bone: low calcium

Question 13

For lead intoxification, describe the mechanisms of heme biosynthesis and inhibition

Answer 13

Decreased lifespan of RBC

Inhibition of heme biosynthesis

Question 14

For mercury intoxification, compare and contrast absorption and signs of toxicity of

Elemental mercury
Mercury inorganic salts
Organic mercury

Answer 14

Elemental =
Absorbed lungs
Weakness, chills, metallic taste, N, cough

Mercury inorganic =
Absorbed in GI, kidneys
Gray mucosa, loosened teeth, irritated gums, renal toxicity, pink disease

Organic = GI tract
Visual disturbances, hearing loss, tremor, mental retardation

Question 15

For edetate calcium disodium, describe MOA

Answer 15

Used for lead poisoning

Calcium salt used to avoid hypocalcemia

Question 16

Describe major use and route of administration for:

Edetate calcium disodium

Answer 16

Used for lead poisoning

IV or IM administration

Question 17

Describe toxicity for

Edetate calcium disodium

Answer 17

Kidneys

Thirst, headache, fatigue

Question 18

Describe MOA for

Succimer

Answer 18

Bio-transformed by attachment of cysteine conjugates in bile

Question 19

Describe major use and route of administration for

Succimer

Answer 19

Used for Ar, Hg, and Pb poisoning

Administration = oral

Question 20

Describe toxicity for

Succimer

Answer 20

N/V, diarrhea, loss of appetite

Question 21

Describe MOA for

Dimercaprol

Answer 21

Chelates -SH groups

Question 22

Describe major use and route of administration for

Dimercaprol

Answer 22

Used for As, Hg, and lead (+ EDTA) poisoning

Administration: IM

Question 23

Describe toxicity for

Dimercaprol

Answer 23

Less effects on kidneys vs. EDTA

Inc. BP + HR
Nausea
Headache

Question 24

Describe MOA for

Penicillamine

Answer 24

Penicillin derivative

Question 25

Describe major use and route of administration for:

Penicillamine

Answer 25

Use:
As, Hg, Pb poisoning
(Also chelates Zn, Cu)

Administration: oral

Question 26

Describe toxicity for

Penicillamine

Answer 26

Long term use =
Skin dryness/scaling
Anemia
Renal toxicity

Question 27

Describe MOA for

Deferoxamine

Answer 27

Binds iron

Question 28

Describe major use and route of administration for:

Deferoxamine

Answer 28

Used for Fe poisoning

Administration: IV or IM

Question 29

Describe toxicity for

Deferoxamine

Answer 29

Allergic =

Itching, wheals, rash

Question 30

Describe MOA for

Deferasirox

Answer 30

Forms complex with iron

Question 31

Describe major use and route of administration for:

Deferasirox

Answer 31

Used for iron overload (patients receiving frequent transfusions, like for sickle cell disease)

Administration; oral

Question 32

Describe toxicity for

Deferasirox

Answer 32

GI

Blood dyscrasias

Renal failure

Question 33

Describe diagnosis of lead poisoning?

Answer 33

Can be easily missed

Blood samples need to look for lead in whole blood

Urine samples could be wrong from nephropathy

Question 34

Describe mercury poisoning diagnosis

Answer 34

Blood: whole blood

Urine: useful for inorganic Hg

Hair