Lecture 4 - Intro to toxicology

Question 1

what is the difference between a toxin and a toxicant?

Answer 1

toxin = from living cells;
toxicant = man made chemical

Question 2

dermal, inhalation, ingestion: 
which has the fastest speed of onset?
which has the slowest?
which is hardest to deconaminate?
which is easiest?

Answer 2

inhalation, dermal;

inhalation, dermal

Question 3

dermal/ingestion/inhalation:
which requires the highest dose for effect?
which requires the smallest dose for an effect?
which has extensive first pass metabolism?

Answer 3

dermal;
inhalation;
ingestion

Question 4

most drug-induced toxicity arises as a result of ______ to reactive species. metabolism via ______ enzymes typically produces more polar, easily excreted compounds

Answer 4

bioactivation;

phase 1/2 (safer)

Question 5

toxic responses:
____ responses occur at a site distant from contact/portal of entry.
immediate responses occur within ___ to ___;
delayed resposnes occur within ___ to ____

Answer 5

systemic;
seconds to hours;
days to years

Question 6

toxic responses:

_____ effects reverse after stopping exposure. _____ effects persist.

Answer 6

reversible, irreversibkle

Question 7

3 phases of toxic responses:

Answer 7

exposure, disposition, toxicodynamics (ie cellular response)

Question 8

what is LOAEL?

Answer 8

lowest observable adverse effect level = lowest dose that provokes an adverse effect in an organism

Question 9

what is NOAEL?

Answer 9

No observable adverse effect level = highest dose that fails to provoke any observable adverse effects

Question 10

of LOAEL and NOAEL, which is used to determine the first dose in man of a new drug?

Answer 10

NOAEL

Question 11

what is the equation for therapeutic index?

a ____ value indicates that the drug is safe

Answer 11

TI = TD50/ED50

high