Intro to Toxicology

Question 1

What is a poison (toxicant)?

Answer 1

Any solid, liquid, or gas when introduced into a biologic system can interfere with the life processes of the cells of that organism by its own inherent properties

Question 2

What are the MOAs of Poisons?

Answer 2

• Attack common receptors
• Compete for metabolites
• Damage membranes
• Alter nucleic acid synthesis

Question 3

What is a Toxin?

Answer 3

• Poison from a biological process
  
  • Biotoxin - general
  • Zootoxin - insect/reptile
  • Mycotoxin - fungal
  • Phytotoxin - plant
  • Phycotoxin - algae

Question 4

Define “toxic”

Answer 4

• Refers to AE
  
  • Ex: arsenic is toxic to the GIT and Kidney

Question 5

Define “toxicosis”

Answer 5

• Disease state of being poisoned
  
  • Ex: arsenic toxicosis = acute onset of vomiting progressing to hemorrhagic diarrhea

Question 6

Define “toxicity”

Answer 6

• Essentially the dose
  
  • Ex: Cute toxicity of Arsenic is 5 mg/kg

Question 7

What is NOEL?

Answer 7

No observed effect level

Question 8

What is NOAEL

Question 9

No observed AE level

Question 10

What is HNTD

Answer 10

Highest Non-toxic Dose

Question 11

What is LD50

Answer 11

• Lethal dose 50
• Quantal Response of a group
• Straight line on semi log or probit paper
• Lethal to 50% of animals defined conditions
• Does not address severity/clinical characteristics
• No relationship to chronic toxicity or other effects

Question 12

What is ED50

Answer 12

Effective Dose 50

Question 13

What is Dose-Response?

Answer 13

• Conflict between 2 forces
• Agent against a biological system
  
  • Dose determines which prevails

Question 14

What is an “agent”?

Answer 14

• Can be many things
  
  • Poison/toxicant
  • Chemical
  • xenobiotic - foreign compound
  • Toxin
  • Elements - lead, selenium, etc
  • Pharmaceuticals
  • Nutrients

Question 15

What is Chronicity factor?

Answer 15

• Acute LD50/90 day LD50
• Measure of cumulative toxicity

Question 16

What is Risk?

Answer 16

• The likelihood of poisoning occurring under the conditions of normal use
• Risk Ratio compares toxicity to use

Question 17

What are the Physiological factors that affect toxicosis outcomes?

Answer 17

• Species
• Breed
• Age
• Sex
• Pregnancy
• Lactation
• Nutritional status
• Health Status

Question 18

What are the environmental factors that affect toxicosis outcomes?

Answer 18

• Season
• Transportation
• Water quality/quantity

Question 19

What other factors affect toxicosis outcomes?

Answer 19

• Dose
• Physical Nature of Agent
• Solubility
• Route

Question 20

What chemical interactions affect toxicosis outcomes?

Answer 20

• Can alter ADME within biological system
• 4 types:
  
  • Additive 2 + 4 = 6
  • Synergistic 2 + 4 = 12
  • Potentiation 0 + 4 = 6
  • Antagonistic 3 + 6 = 7

Question 21

What is the diagnostic strategy for intoxications?

Answer 21

• History
• Clinical signs and progression
• Clinical Pathology (serum chem, CBC, Urinalysis)
• Analytical Toxicology
• Necropsy findings
• Histopathy

Question 22

How should intoxications be managed?

Answer 22

• Treat the patient not the poison
• Each patient and toxicant are unique
• General guidelines
  
  1. Stabilize airway, breathing, circulation
  2. Get more history and re-evaluate
  3. Prevent further absorption
  4. Give specific antidote if available
  5. Enhance elimination

Question 23

What is a Part per million?

Answer 23

• 1a + 999,999b
• 1ppm = 1mg/kg = 1 ug/g

Question 24

What is a part per billion (ppb)?

Answer 24

• 1a + 999,999,999b
• 1ppb = 1 ug/kg = 1 ng/g