Toxicology Basics - Intro & Toxicokinetics

Question 1

therapeutic index equation

Answer 1

TI = LD50 / ED50

Question 2

standard safety margin equation

Answer 2

SSM = LD1 / ED99

Question 3

acute toxicant exposure vs chronic toxicant exposure

Answer 3

acute: exposure to single or multiple doses over 24 hrs
chronic: exposure for 3 months or longer

Question 4

alternative name for a poison

Answer 4

toxicant

Question 5

poison that originates from biological processes “biotoxin”

Answer 5

toxin

Question 6

quantity or amount of poison that causes a toxic effect

Answer 6

toxicity

Question 7

disease state that results from exposure to a poison

Answer 7

toxicosis

Question 8

amount of toxicant received per animal

Answer 8

dose

Question 9

amount of toxicant per unit animal mass or weight; time can also be included as a metric

Answer 9

dosage

Question 10

how the animal is exposed to the toxicant; oral, feed, drink, dermal, inhalation, etc.

Answer 10

route of exposure

Question 11

highest dose of a toxicant where no toxic effects are observed

Answer 11

threshold dose

Question 12

acute dose resulting in death; usually presented as the dose resulting in death of 50% of animals (LD50); can also be expressed as dose resulting in death of 10% of animals (LD10)

Answer 12

lethal dose

Question 13

lowest concentration of a chemical in a matrix (usually feed or water) that causes death; commonly used for lethality for fish or wildlife species

Answer 13

lethal concentration

Question 14

dose of a drug or toxicant that produces some desired effect in 50% of the population

Answer 14

effective dose

Question 15

bioavailability equation

Answer 15

B = AUCRoute X x DoseIV
AUCIV x DoseRoute X

Question 16

What factors affect the passage of toxicants across biological membranes?

Answer 16

concentration gradient across the membrane
surface area of the membrane
toxicant permeability
macromolecule binding

Question 17

factors of small intestinal absorption

Answer 17

largest barrier to intestinal absorption is permeability – factors include solubility, metabolism, transporters and transit time

Question 18

factors of dermal absorption of toxicants
can a water-soluble toxicant be expected to cross the skin

Answer 18

surface area & perfusion
lipophilic and hydrophilic
YES

Question 19

What is the difference between diffusion- and perfusion-limited drug distributions?

Answer 19

Diffusion limited: based on easiness of diffusion/how quick it can get across; weak acids/bases easiest to in/out of tissues

Perfusion limited: based on blood flow to certain organs, brain/liver/intestines/kidney will be affect the fastest due to amount of blood flow they receive

Question 20

Does metabolism always involve the disappearance of a toxicant? What other role can metabolism play in toxicant exposure?

Answer 20

no, in general metabolism is detoxifying but metabolic activation is sometimes required for toxic effect
metabolites can be active, toxic, inactive, nontoxic

Question 21

how are toxicants eliminated from the body? main ones?

Answer 21

urine ** renal
feces ** hepatic
sweat
saliva
milk
exhalation

Question 22

factors of renal elimination and factors of GFR

Answer 22

filtration, active secretion, reabsorption
blood flow
protein binding

Question 23

factors of hepatic elimination

Answer 23

blood flow
protein binding
enzymatic acitivty

Question 24

Be able to describe how the terminal half-life of a toxicant can influence the treatment of a poisoned animal.

Answer 24

important indicator of treatment duration or residue time