EXAM #5: INTRODUCTION TO TOXICOLOGY

Question 1

What is toxicology?

Answer 1

Subtopic of pharm concentrating on the effects and properties of toxic substances

Question 2

What does it mean that poisoning if situational and quantitative in nature?

Answer 2

Any substance at the right DOSE and for the right amount of TIME can be a poison

Question 3

Why do we study toxicology?

Answer 3

1) Protect us from adverse effects of toxicants

2) To develop improved toxicants

Question 4

What is the definition of the LD50?

Answer 4

Dose at which 50% of animals die

Question 5

What is the definition of the TI i.e. how do you calculate the TI?

Answer 5

LD50/ED50

Question 6

What does a big TI indicate?

Answer 6

Safe drug

Question 7

What is the ALD?

Answer 7

Average Lethal Dose

*Note that this is estimated from accidental deaths in humans

Question 8

What is the primary determinant of toxicity?

Answer 8

Dose–you want to know:

• How much?
• When?

Question 9

How do you clinically manage poisoning?

Answer 9

1) Support patient’s vitals:
- ABCs
2) Reduce or remove drug

Question 10

What are two treatments that can be considered for an “unconscious for unknown reason” type patient?

Answer 10

1) Glucose

2) Naloxone

Question 11

What is a toxidrome?

Answer 11

Group of signs and symptoms constituting the basis for the diagnosis of poisoning

Question 12

What are two emesis inducers?

Answer 12

1) Apomorphine

2) Syrup of Ipecac

Question 13

What are the contraindications to emesis inducers?

Answer 13

• Chemical pneumonitis e.g. WD40

- Acid or alkali agents

Question 14

What is the MOA of activated charcoal?

Answer 14

Very large SA that binds to toxic agent

Question 15

When should charcoal be administered?

Answer 15

Within 30 min. or ingestion

Question 16

What cross reaction do you need to remember about activated charcoal?

Answer 16

Efficacy of other medications will decrease with charcoal administration

Question 17

What is the antidote to organophosphate poisonin e.g. Sarin, insecticide bomb…etc?

Answer 17

Pralidoxime or 2-PAM
- Binds organophosphate

Atropine= blocks muscarinic effects

Question 18

What is the MOA of cyanide poisoning?

Answer 18

Deactivation of cytochrome C in mitochondrial membrane

CNS and cardiac tissue most affected

Question 19

What is the antidote for cyanide poisoning?

Answer 19

Amyl nitrite
Sodium nitrite
Sodium thiosulfate

*All with O2

Question 20

What is the most potent poison known to man?

Answer 20

Botulinum toxin (prevents ACh release from nerve terminal)

Question 21

What are BAL, EDTA, DMSA, DMPS, calcium EDTA, and deferoxamine used to treat?

Answer 21

Heavy metal poisoning

Question 22

What is DMSA specifically indicated for?

Answer 22

Treatment of:

• Arsenic
• Mercury
• Lead poisoning

Question 23

How is DMSA dosed?

Answer 23

10mg/kg PO for 5x days if OVER 12

- Under 12, add an additional 14 days for 19 total days of treatment

Question 24

What is the antidote for Botulinsm toxin?

Answer 24

Antibody for Botulism A, B, and E

Question 25

What is the MOA of the drugs used to treat cyanide poisoning?

Answer 25

1) Oxidize Hb to methemoglobin 2) Binds cyanide to make cyanmethemoglobin ADD Sodium thiosulfate 3) Cyanmethemoglobin-->thiocyanate and Hb

Question 26

How can ethylene glycol/methanol/isopropyl alcohol poisoning be treated without an antidote?

Answer 26

Ethanol that will competitively inhibit alcohol dehydrogenase

Question 27

What is the antidote for ethylene glycol/ methanol/ isopropyl alcohol poisoning?

Answer 27

Fomepizole

Question 28

What is the MOA of Fomepizole?

Answer 28

Blocks alcohol dehydrogenase from making toxic metabolites

Question 29

How does the affinity of CO for Hb compare to O2?

Answer 29

CO has 210x greater affinity

Question 30

What is the treatment for CO poisoning?

Answer 30

Hyperbaric O2

Question 31

What is the classic appearance of CO poisoning?

Answer 31

Cherry red lips/gums

Question 32

How does an overdose of Warfarin present?

Answer 32

Excessive bleeding e.g: - Hemoptysis - Bruising - Bleeding from nose or gums - Blood in the urine/stool

Question 33

What is the antidote for Warfarin?

Answer 33

Vitamin K

Question 34

What are the antidotes for opoid overdose? What is the difference?

Answer 34

Naloxone= acute OD b/c of short half-life Naltrexone= longer duration of action

Question 35

What is methemoglobinemia?

Answer 35

Heme iron is in the Fe3+ state that cannot bind O2

Question 36

What is the antidote for methemoglobinemia?

Answer 36

Methylene Blue

Question 37

What is the MOA of Methylene Blue for Methemoglobinemia?

Answer 37

Direction chemical reduction of methemoglobin back to Hb

Question 38

List the signs/ sx associated with a sympathomimetic toxidrome.

Answer 38

Mydriasis HTN Tremor Hyperthermia

Question 39

What are the drugs associated with sympathomimetic toxidromes?

Answer 39

Cocaine Amphetamines PCP

Question 40

List the signs/ sx associated with a sedative/hypnotic toxidrome.

Answer 40

Coma Decreased respiratory drive Miosis or mydriasis Hypotension

Question 41

What are the common drugs that lead to a sedative/hypnotic toxidrome?

Answer 41

Alcohol Barbiturates Benzodiazepines

Question 42

List the signs/ sx associated with a opiate toxidrome.

Answer 42

Coma Respiratory depression Miosis

Question 43

List the signs/ sx associated with an anticholinergic toxidrome.

Answer 43

CNS agitation Mydriasis Fever Dry skin Flushing Urinary retention Remember, "Hot Dry Red Mad and Blind"

Question 44

What is the mnemonic to remember the toxidrome associated with Cholinergic agents?

Answer 44

SLUDGE ``` Salivation Lacrimation Urination Diaphoresis GI Upset Emesis ```

Question 45

List the signs/ sx associated with a TCA toxidrome.

Answer 45

``` Agitation-->coma Mydriasis Dysrhythmia Convulsions Hypotension ```

Question 46

List the signs/ sx associated with a salicylate/aspirin toxidrome.

Answer 46

``` Increased respirations Diaphoresis Tinnitus Agitation Hyperpyrexia ```