Intro to Tox & Calcs Flashcards
What is toxicology?
The study and science of poisons (toxicants)
What is a toxicant?
A substance (poison) that may interfere with life processes or biological functions
What other sciences is toxicology related to?
Pharmacology, clinical medicine, infectious diseases, pathology, histology, physiology, biochemistry, anatomy
What are xenobiotics?
Foreign chemicals not produced by the body
What are the two sources of toxicants?
Natural or synthetic
What are some examples of natural toxicants?
Plant, animal, mineral, fungi or bacteria, gas
What are some examples of synthetic toxicants?
Insecticides, organophosphates, chlorinated hydrocarbons, organic herbicides
What is poison from a biological process?
Biotoxin
Define toxic.
Used to describe the deleterious or undesirable effects of a poison
What is toxicosis?
The disease caused by exposure to a toxin
What is the difference between acute toxicity and subacute toxicity?
Acute toxicity is the effect of a single dose or multiple doses over 24 hours.
Subacute toxicity is the effect produced by daily exposure from 1 day to 30 days.
What is the difference between chronic toxicity and subchronic toxicity?
Chronic toxicity is the effect produced by daily exposure from 3 months or more.
Subchronic toxicity is the effect exposed by daily exposure from 30 to 90 days.
What is chronicity factor?
The ratio between acute LD50 and chronic LD50.
Toxicity of any substance is influenced by which several factors?
Species, breed, sex, individual, age, dosage of poison, duration of exposure, idiosyncrasies
T/F: Rapidly metabolized compounds will have a low chronicity factor.
True
Development of tolerance due to increased metabolism will do what to the chronicity factor?
Decrease it
Compounds with a cumulative effect will have a high or low chronicity factor?
High
A chronicity factor of what will indicate a relatively cumulative toxin?
Greater than 2
Give an example of a cumulative toxicant and a rapidly excreted toxin.
Cumulative= Warfarin Excreted= Caffeine
Extremely toxic
1 mg/kg or less
Highly toxic
1-50 mg/kg
Moderately toxic
50-500 mg/kg
Slightly toxic
0.5-5 g/kg
Practically nontoxic
5-15 g/kg
Relatively harmless
15 g/kg
The highest nontoxic dose (HNTD)
The highest or largest dose which does not result in undesirable or toxic alterations
Maximum tolerated dose or minimal toxic dose (MTD)
Similar to highest nontoxic dose
Toxic dose low (TDL)
The lowest dose which produces toxic alterations and administering twice this dose will NOT cause death
Toxic dose high (TDH)
The dose which produces toxic alterations and administering twice this dose WILL result in death
No effect level (maximum nontoxic level)
The amount of a chemical that can be ingested without causing any deaths, illness or toxic alterations in any animal for the stated period
Lethal dose
Dose that causes death in any animal during a period of
observation
What kind of response is lethal dose?
All or none response
LD 0
Highest dose that does NOT cause death
LD 50
Median lethal dose, kills 50% of the animals in the group
LD 100
Lowest dose that kills all the animals in the group
What is a hazard?
The danger from the possibility of exposure
How can risk factor be calculated?
The ratio between toxicity and use level
Drugs can be poisons and poisons can be drugs. What is the difference?
The DOSE is the difference!
1 Gal = ? mL
4,000 mL
1 qt = ? mL
1,000 mL
1 kg = ? L
1 L
1 ton = ? kg
907 kg
1 pt = ? mL
500 mL
1 oz = ? g
30 g
1 kg = ? lb
2.2 lb
What is the most common method of expressing
concentrations in veterinary toxicology?
Parts per million (ppm)
1 ppm
1 mg/ kg = 1 mg/ L = 1 mcg/ g
1 ppb
1 mcg/ kg = 1 mcg/ L
ppm to percentage
1 ppm = 0.0001%
To convert from ppm to %
Move decimal point 4 places to the LEFT
To convert from % to ppm
Move decimal point 4 places to the RIGHT
Weight/ volume for 1%
1g/ 100 mL
1 mg%
1mg/ 100mL
Dilution calculation review
Vol from stock sol = % required dilution / % stock solution X total vol needed
g/ ton
1 g/ ton = 1.1 mg/kg
100g/ ton
100 g/ ton = 110 ppm
Toxicity (mg/kg)
ppm in feed X % body weight feed consumed daily
1 lb/ acre
1 lb/ acre = 7mg/ kg
