Toxicology

Question 0

TLV-TWA v TLV-C v PEL

Answer 0

Threshold limit values: time weighted averages v ceiling

Permissible exposure limits (fed regulations)

Question 1

Margin of Safety

Answer 1

LD1/ED99

Question 2

Bioaccumulations v biomagnification

Answer 2

compound persistent in body v accum with each food chain link

Question 3

Pharmacokinetics v pharmacodynamics

Answer 3

kinetics: how body impacts drug
dynamics: how drug impacts body

Question 4

Pharmacokinetic: change absorption

Answer 4

impact tract function (motility and/or absooprtion)
alter content (Ca2+ or pH)

Question 5

Pharmacokinetic: change distribution

Answer 5

• Plasma protein binding (albumin) –> more free drug –> more toxicity
• tissue binding displacement

Question 6

Example of plasma protein binding displacement

Answer 6

salicylates (aspirin) displaces warfarin and phenytoin (anti-epileptic) from albumin
(increases toxicity of warfarin and phenytoin)

Question 7

Example of tissue binding displacement

Answer 7

quinidine displaces digoxin from tissue (if taken within 24 hours)

Question 8

Pharmacokinetics: change metabolism

Answer 8

Induce or inhibit metabolism

Question 9

Example of metabolism inducer

Answer 9

phenobarbital (slow acting; requires protein producction)

Question 10

Example of metabolism inhibitor

Answer 10

ketoconazole (CYP3A4)

cimetidine (H2 blocker)

Question 11

Pharmacokinetics: change excretion

Answer 11

weak acid transport in proximal tubule (change this mechanism)
pH of urine

Question 12

Drug that alters weak acid transport in proximal tubule?

Answer 12

probenicide blocks –> increase half life of drugs that use this mechanisms (ex penicillin)

Question 13

Drugs that alter pH of urine

Answer 13

sodium bicarb (increases elim of weak acids)
ammonia chloride, ascorbic acid (""bases)

Question 14

Naloxone pharmacodynamics

Answer 14

true antagonist of opiates

Question 15

Tamoxifen pharmacodynamics

Answer 15

partial antagonist to estrogen receptor

Question 16

Gingko biloba shouldn’t be taken with what? why?

Answer 16

NSAIDs

inhibit platelet aggregation –> increased bleeding risk

Question 17

Grapefruit juice shouldnt be taken with what? why?

Answer 17

calcium channel blockers (CCB) (ex. verapamil)

grapefruit juice inhibits CYP3A4 –> more free CCB –> more toxicity (hypotension and myocardial depression)

Question 18

What should not be taken with ketoconazole? why?

Answer 18

CYP3A4 drugs

ketoconazole (like grapefruit juice) inhibits CYP3A4 –> more toxicity

Question 19

What should not be taken with warfarin?

Answer 19

phenobarbital. phenobarbital induces drug metab (makes warfarin less potent)

Question 20

What should not be taken with acetaminophen?

Answer 20

ethanol

induces the “overdose pathway” via CYP2E1 metabolism –> liver enzymes; necrosis

Question 21

HOw do you treat acetaminophen overdose?

Answer 21

N-acetylcysteine withhin 15-24 hours; will bind metabolite

Question 22

Basics of poison management

Answer 22

airway- no obstruct
breathing- eval, blood gas
circulation- pulse, pressure
dextrose-thiamine- if altered CNS, can prevent neuron death

Question 23

How to treat cyanide poisoning?

Answer 23

stabilize
amyl nitrite/sodium nitrite
sodium thiosulfate (kit)

Question 24

Iron poisoning clinical signs? treat?

Answer 24

vomit, diarrhea; remission; shock, seizure, liver failure

treat: deferoxamine (chelator); monitor urine color and serum Fe levels

Question 25

Lead poisoning signs? treat?

Answer 25

nausea, constipation/diarrhea, ab pain; urinary exrcretion; MR/personality changes; blue lead line on gums, peripheral neuropathy (wrist/foot drop)
Treat: dimercaprol and calcium EDTA

Question 26

Ethylene glycol poisoning signs and treat?

Answer 26

antifreeze
increased osmolar gap–> anion gap acidosis (lab)
Treat: ethanol or fomepizole (expensive)

Question 27

Ricin poisoning mechanism

Answer 27

castor bean plant

binds 60s ribosome–> protein synthesis disruption

Question 28

Amanita mushroom mechanism? treat?

Answer 28

cyclopeptide inhib RNA pol II –> decr protein synthesis –> cell necrosis
possible liver transplant?