Exam 3 Toxicology

Question 1

Defined as the range of response per dose?

Answer 1

biological variation

Question 2

Defined as a greater-than-normal reaction to a drug?

Answer 2

hypersusceptibility

Question 3

Defined as a response of the patient to the drug is qualitatively different from the usual or expected response?

Answer 3

drug idiosyncracy

Question 4

Age - Pediatrics: dosing is based on the ___ of the child?

Answer 4

weight

Question 5

Age - Geriatrics: what’s the rule for geriatric dosing?

Answer 5

give lower dose

Question 6

Pathological State: liver disease: in most cases, drug metabolism is reduced due to diminished function of ____ system, dosing must be _____

Answer 6

cytochrome P-450

reduced

Question 7

Pathological State: renal disease: results in renal impairment of drug excretion; dosing must be modified on the basis of _____ values of the drug

Answer 7

renal clearance

Question 8

Defined as increasing amounts of drugs are required to produce a consistent effect?

Answer 8

drug tolerance

Question 9

Defined as a rapid development of tolerance?

Answer 9

tachyphylaxis

Question 10

Defined as a quantitative measure of the therapeutic window?

Answer 10

therapeutic index

Question 11

What is therapeutic index?

Answer 11

a single number that quantifies the relative margin of safety of a drug in a population of people OR how selective the drug is in producing the desired effects.

Question 12

Do dentists want to see a large TI or small TI?

Answer 12

large TI, because a small TI is a small window requiring monitoring

Question 13

What is TD50?

Answer 13

dose of the drug that causes a toxic response in 50% of the population

Question 14

What is ED50?

Answer 14

does of the drug that is therapeutically effective in 50% of the population

Question 15

Defined as a result of a single, large exposure to the toxic agent; seen within minutes/hours, and MAYBE weeks to months following initial exposure?

Answer 15

acute toxicity

Question 16

Defines as the effect of a toxic insult that occurs over a prolonged period of time; seen after years of exposure and long after Pt is no longer exposed to the toxin?

Answer 16

chronic toxicity

Question 17

Toxins must cross an _____ to be absorbed systemically

Answer 17

epithelial layer

Question 18

Name the 3 primary sites of absorption into the body?

Answer 18

GI tract
Respiratory tract
Skin

Question 19

Rate of distribution to a particular tissue is related to ___?

Answer 19

the amount of blood flow to the tissue

Question 20

Organs with a lot of blood flow?

Answer 20

brain
liver
kidney

Question 21

Organs with less blood flow?

Answer 21

fat

bone

Question 22

Concentration of the toxin in each tissue is determined by ____?

Answer 22

the affinity of the toxin for the tissue

Question 23

Defined as a being metabolized to inert products in the liver (active to inactive)?

Answer 23

detoxication

Question 24

Detoxification uses ____ liver enzyme system to create ____ molecules to allow for elimination.

Answer 24

P450

water soluble

Question 25

Defined as nontoxic materials converted into toxic materials after undergoing metabolism in the liver (inactive to active)?

Answer 25

toxication

Question 26

Name 2 elimination pathways?

Answer 26

1) renal excretion of water-soluble molecules | 2) respiratory excretion of gases and volatile compounds

Question 27

Defined as altering structure of proteins, lipids, carbohydrates, and nucleic acids so severely that cellular integrity is lost?

Answer 27

macromolecular damage

Question 28

Tissue-damaging agents are ____ and most commonly affect what systems exposed to the environment?

Answer 28

non-specific | skin, eyes, respiratory system

Question 29

Defined as reacting chemically with biologic macromolecules and other chemicals?

Answer 29

reactive species

Question 30

Reactive species are more ____ in their site of action

Answer 30

specific

Question 31

Reactive species cause damage where?

Answer 31

in the tissues in which they are generated

Question 32

Name a reactive species example?

Answer 32

carbon tetrachloride

Question 33

How does carbon tetrachloride become reactive?

Answer 33

metabolized by liver with oxygen to form toxic organic free radicals that can then attack kidney, liver and cause liver cancer

Question 34

The immune response can be triggered by toxins in what 2 ways?

Answer 34

1) hypersensitivity reactions (allergic) | 2) autoimmune reactions

Question 35

Defined as altering importan metabolic pathways, signaling pathways or interacting with critical receptors?

Answer 35

enzyme and receptor-mediated toxicity

Question 36

Enzyme-mediated nerve gases and pesticides are ____ inhibitors

Answer 36

acetylcholinesterase

Question 37

Nerve gases and pesticides cause what?

Answer 37

excessive concentration of acetylcholine in synaptic cleft

Question 38

Excess acetylcholinesterase in synaptic cleft causes what symptoms?

Answer 38

``` slowed heart rate breathing difficulties sweating diarrhea salivation vomiting weakness convulsions pinpoint pupils ```

Question 39

Describe the enzyme-mediated process that prevents the generation of ATP?

Answer 39

cyanide bindes heme iron to active site of cytochrome C oxidase

Question 40

Describe the receptor-mediated toxicity example?

Answer 40

carbon monoxide binds strongly to iron in active site of hemoglobin, preventing oxygen binding and reducing oxygen carrying capacity

Question 41

Defined as the transformation of a normal cell to a neoplastic cell?

Answer 41

carcinogenesis

Question 42

Defined as a chemical, physical or biological substance that can cause transformation?

Answer 42

carcinogen

Question 43

Describe a carcinogenesis example?

Answer 43

chronic consumption of alcohol lead to cirrhosis, which can lead to liver cancer

Question 44

Describe how carcinogenesis works?

Answer 44

initiator damages DNA, causes mutation, mutation replicated, if mutation affects genes that control cell cycle replication, cancer is initiated

Question 45

Defined as a substance that can induce a birth defect?

Answer 45

teratogen

Question 46

What are most teratogens?

Answer 46

reactive species or metabolic inhibitors

Question 47

What are potent teratogens?

Answer 47

substances that can inhibit intracellular signals

Question 48

Name some ways teratogens work?

Answer 48

``` alter DNA/chromosomes fetus exposure means mother exposure functional deficit growth retardation death ```

Question 49

What organ may recover after toxic exposure?

Answer 49

liver

Question 50

What organs cannot recover after toxic exposure?

Answer 50

heart, neurons

Question 51

What prevents many toxins from entering the CNS?

Answer 51

blood brain barrier

Question 52

Name some ways cancer cells use selective toxicity to survive and replicate?

Answer 52

``` PERMS proteins enzymes receptors metabolic pathways structures ```

Question 53

Selective toxicity attack targets that are unique to the pathogen/cancer cell that are WHAT 3 things?

Answer 53

1) not present in the host 2) similar but not identical to those in the host 3) shared by the host, but that vary in importance between the pathogen and the host

Question 54

Drugs exhibit the least toxicity when they what?

Answer 54

target a unique difference

Question 55

Drugs exhibit the most toxicity when they what?

Answer 55

target common pathways

Question 56

Name a highly selective drug because of the large difference between the therapeutic and toxic concentrations?

Answer 56

penicillin

Question 57

Drugs that are less selective are what?

Answer 57

affect pathogenic and normal cells, are not as safe, have narrow therapeutic indext

Question 58

Give an example of a unique drug target?

Answer 58

antibiotics targeting cell wall

Question 59

Give an example of a bad unique drug target?

Answer 59

anti fungal drugs (can alter human cells as well); low therapeutic index; significant side effects

Question 60

Give an example of a bad unique DRUG and what is CAUSES?

Answer 60

amphoteracin = ototoxicity

Question 61

Name examples of selective inhibition of similar targets?

Answer 61

inhibiting protein synthesis = antibiotics prevent emergence of protein from ribosome = macrolides disrupt decoding of mRNA = aminoglycosides

Question 62

Defined as drugs that produce an effect on the cancer cell than the host and has a narrow therapeutic index?

Answer 62

common targets

Question 63

Name an example of common targets?

Answer 63

inhibiting cancer cell growth = mutated tumor cells using same machinery as normal cells

Question 64

Side effects of targeting cancer cell growth?

Answer 64

``` chemotherapy side effects loss of hair mouth sores skin problems GI problems (diarrhea) Sex cells (infertility) ```