Principles of Toxicology

Question 1

Father of Toxicology

Answer 1

Paracelsus- Swiss physician

Question 2

toxic

Answer 2

something poisonous, or causes adverse effects

Question 3

toxicology

Answer 3

the study of poisons

concerned with identification, treatment and assessing risks of poisons

Question 4

toxicant

Answer 4

compounds that cause toxicity

may be natural or man-made xenobiotic

Question 5

xenobiotic

Answer 5

foreign substance

Question 6

antidote

Answer 6

• remedy to counteract poison
• usually refers to any substance that prevents/relieves the effects of a toxicant
• no antidote works on all toxins and some can be potentially harmful

Question 7

toxins

Answer 7

consist of manmade chemicals and natural products

Question 8

classify as extremely toxic

Answer 8

< 1 mg/kg

ex: botulism, strychnine

Question 9

classify as highly toxic

Answer 9

1-50 mg/kg

ex: nicotine

Question 10

classify as moderately toxic

Answer 10

50-500 mg/kg

ex: aspirin, foxglove, acetaminophin

Question 11

classify as slightly toxic

Answer 11

0.5-5 g/kg

ex: salt, grapes

Question 12

classify as practically non-toxic

Answer 12

5-15 g/kg

Question 13

classify as relatively harmless

Answer 13

> 15 g/kg

ex: water

Question 14

additive chemical interaction

Answer 14

sum of the effects

1 + 1 = 2

Question 15

antagonistic chemical interactions

Answer 15

blocks or brings down the negativity of the effects

1 + 1 = 1

Question 16

synergistic chemical interaction

Answer 16

compounds work together and significantly increase the effects

1 + 1 = 4

Question 17

factors related to the toxicant

Answer 17

• chemical structure
• affinity for some molecules
• what the toxicant is mixed in (carrier, adjuvant)

Question 18

factors related to exposure

Answer 18

• dose
• route of entry
• duration of exposure

Question 19

factors related to the subject

Answer 19

• species
• age of animal (young and old more susceptible)
• health status
• prior exposure
• physiological complications

Question 20

factors related to the environment

Answer 20

• climate/temperature
  
  • chemicals degrade faster at higher temperatures, body temp dictates how drugs are metabolized
• pH of stomach
  
  • affects absorption of chemicals

Question 21

examples of species differences

Answer 21

• cats deficient in glucuronidation
• dogs deficient in acetylation
• pigs deficient in sulfation
• pregnancy also alters metabolism

Question 22

acute exposure

Answer 22

single dose exposure or several doses within a 24 hour period

Question 23

sub-acute/subchronic exposure

Answer 23

exposure over 7-90 days

Question 24

chronic exposure

Answer 24

protracted exposure (6 months - lifetime)

Question 25

dose-response relationship

Answer 25

* central concept of toxicology * assumes a **cause and effect relationship** and that **response is proportional to dose**

Question 26

4 concepts important to toxicokinetics

Answer 26

* Absorption * Distribution * Excretion * Metabolism

Question 27

most important veterinary toxicants are absorbed via which routes?

Answer 27

**oral** and **dermal**

Question 28

job of metabolism

Answer 28

**detoxifies a compound** and **increases its elimination**

Question 29

bioactivation

Answer 29

* when **metabolism increases the toxicity of a compound** * ex: benzoapyrene, aflatoxin, acetaminophen * also happens with some drugs

Question 30

4 steps in the mechanism of toxicity

Answer 30

1. **delivery from site of exposure to target** 2. **reaction of the ultimate toxicant** with the **target molecule** 3. **cellular dysfunction** and **resultant toxicities** 4. **repair** (apoptosis, tissue regeneration) or **disrepair** (tissue necrosis, fibrosis, cancer)

Question 31

2 main ways toxicants cause toxicity

Answer 31

1. **cellular damage** (can result from free radical damage, inhibition of energy production, disruption of enzyme function) 2. **organ system dysfunction** (not associated with specific cellular injury, but lethal to intact organism)

Question 32

10 of the most dangerous foods for dogs

Answer 32

1. alcohol 2. avocados 3. chocolate 4. coffee and caffeine 5. fruit with pits and seeds 6. grapes and raisins 7. macadamia nuts 8. garlic and onions 9. xylitol 10. yeast dough