Pharmacodynamics

Question 1

What is a receptor?

Answer 1

component of a cell to which drug binds to initiate the chain of events that leads to a biological response

Question 2

what is the duration of action for most drugs directly related to?

Answer 2

time the drug is bound to the receptor

Question 3

what happens once the drug is cleared from the bloodstream?

Answer 3

actions will be terminated

Question 4

what type of drug will persist for several weeks even after the drug has been cleared from the body?

Answer 4

corticosteroids

Question 5

what happens when drugs irreversibly bind to an inhibit enzyme?

Answer 5

their effects persist much longer than the free drug in the plasma

Question 6

what drug-receptor interactions are reversible?

Answer 6

electrostatic interactions, hydrogen bonds, van der waals forces, and hydrophobic interactions

Question 7

what drug-receptor interactions are irreversible?

Answer 7

covalent binding

Question 8

what is a intracellular receptor?

Answer 8

hormone or drug that crosses the plasma membrane that stimulates intracellular receptor

Question 9

what hormones and drugs bind to intracellular receptors?

Answer 9

corticosteroids, mineralocorticoids, sex steroids, vitamin D, thyroid hormone

Question 10

what binds to protein tyrosine kinase?

Answer 10

insulin, epidermal growth factor, platelet derived growth factor

Question 11

which ligand-gated channels excites and which inhibits?

Answer 11

Nicotinic acetylcholine receptor - excitatory, depolarizes
GABA receptor - inhibitory, hyperpolarizes

Question 12

what binds to the ligand-gated ion channels (specific for nicotinic vs GABA)?

Answer 12

Nicotinic - acetylcholine
GABA - GABA, benzodiazepines
Ca++/Na+ - glutamate

Question 13

what happens when a drug binds a G-coupled receptor?

Answer 13

G-protein activates hydrolysis of GTP->GDP

Question 14

What does receptors linked to Gs do to the formation of cAMP?

Answer 14

stimulate formation of cAMP

Question 15

what does receptors linked to Gi do to the formation of cAMP?

Answer 15

inhibit formation of cAMP

Question 16

what hormones and drugs bind to Gs to stimulate cAMP formation?

Answer 16

epinephrine (B1 and B2)
norepinephrine (B1)
isoproterenol (B1 and B2)
dobutamine (B1)
histamine (H2)
FSH
ACTH

Question 17

what hormones and drugs bind to Gi to decrease cAMP formation?

Answer 17

norepinephrine (a2)
epinephrine (a2)
dexmedetomidine (a2)
acetylcholine (M2)
morphine (u,k,d)
serotonin (5-HT1)

Question 18

what drugs and hormones bind to GQ to stimulate formation of IP3/DAG?

Answer 18

acetylcholine (M1 and M3)
norepinephrine, epinephrine (a1)
phenylephrine (a1)
serotonin (5-HT1c)

Question 19

what are some non-receptor mediated effects?

Answer 19

simple chemical interactions with body components, other drugs, and infective agents

Question 20

what does IP3 and DAG do?

Answer 20

IP3 stimulates Ca++ release from intracellular store
DAG stimulates protein kinase C -> Ca++ pumped out

second messenger, influx of Ca2+ into ER

Question 21

how many drugs can combine with one receptor?

Answer 21

one drug

Question 22

How is the amount of drug bound compared to the amount of free drug available?

Answer 22

negligible

Question 23

what type of curve is this?

Answer 23

dose-response curve

Question 24

what is EC50?

Answer 24

dose required for half maximal effect

Question 25

what type of curve is this?

Answer 25

Quantal dose-response curve

Question 26

which curve is in relation to a single animal and which is in relation to a population?

Answer 26

single animal - graded dose-response curve population - quantal dose-response curve

Question 27

which curve has a response of all or none?

Answer 27

quantal dose-response curve

Question 28

How is the quantal dose-response curve obtained?

Answer 28

transformation of data used for frequency distribution plot

Question 29

which curves can you use to calculate ED50?

Answer 29

quantal dose-response curve and dose-response curve

Question 30

what is the equation for therapeutic ratio?

Answer 30

LD50/ED50

Question 31

define affinity

Answer 31

measures binding of drug to receptor

Question 32

what is Kd

Answer 32

concentration needed to produce half maximal binding

Question 33

define potency

Answer 33

dose required to produce a given effect

Question 34

define efficacy

Answer 34

degree of biological response produced by binding of a particular drug to the receptor

Question 35

what is the relationship between potency and efficacy?

Answer 35

not related

Question 36

define intrinsic aftivity

Answer 36

ability of a drug to initiate a response synonymous with efficacy

Question 37

what type of activity do agonists have?

Answer 37

affinity and intrinsic activity

Question 38

what type of activity do antagonists have?

Answer 38

affinity and no intrinsic activity

Question 39

what type of activity do partial agonists have?

Answer 39

affinity and lower intrinsic activity

Question 40

what is drug X and Y in the top graph and then the bottom graph?

Answer 40

top X and Y - full agonists bottom X and Y - partial agonists

Question 41

what causes a maximum shift of receptors to the activated state?

Answer 41

agonist

Question 42

what blocks a response to an agonist?

Answer 42

antagonist and partial antagonist to full agonist

Question 43

what are the types of antagonists?

Answer 43

competitive non-competitive functional chemical

Question 44

what type of antagonist takes receptors out of play?

Answer 44

non-competitive

Question 45

what type of antagonists bind to receptor and compete with agonist?

Answer 45

competitive

Question 46

what type of antagonist produces opposing physiological effect?

Answer 46

functional (physiological)

Question 47

what type of antagonist neutralizes chemically?

Answer 47

chemical

Question 48

how much intrinsic activity to competitive antagonists have?

Answer 48

0

Question 49

how does a competitive antagonist shift a dose response cuve?

Answer 49

to the right

Question 50

which antagonist binds irreversibly to the receptor? what does this do to the agonist?

Answer 50

bind irreversibly to receptor so agonist cannot bind

Question 51

How is EC50 affected by non-competitive antagonists?

Answer 51

might or might not change maximum response is decreased

Question 52

what produces a response but with lower efficacy?

Answer 52

partial agonists

Question 53

How is tolerance seen in pharmacokinetics?

Answer 53

drug induces its own metabolism drug may increase metabolism of another drug dec plasma conc, dec biologic effect

Question 54

How is tolerance seen in pharmacodynamics?

Answer 54

usually due to receptor down or up regulation ex beta receptor agonists or antagonists (opioids)

Question 55

How can increased drug activity be induced?

Answer 55

chemically induced, surgically induced, antagonist induced, deficiency in degrading enzymes, competition for binding sites, physiologic synergism

Question 56

when do we see adverse effects?

Answer 56

when there are multiple responses to a drug due to the presence of multiple receptors being activated at different dose levels

Question 57

what are drug examples that several dose-dependent responses can be obtained with one drug?

Answer 57

phenothiazines, antihistamines, CNS depressants

Question 58

are drugs more selective or specific?

Answer 58

at most selective rarely specific

Question 59

what are the two responses drug selectivity can have?

Answer 59

therapeutic and adverse

Question 60

Define dose dependent toxicity

Answer 60

if an adverse reaction is mediated by the same receptor-effector mechanism

Question 61

what is an overextensions of the therapeutic effect?

Answer 61

dose-dependent toxicity

Question 62

what type of drug is added after the control?

Answer 62

competitive antagonist

Question 63

what type of drug is added to epi in this curve?

Answer 63

non-competitive antagonist

Question 64

what type of drug is each line?

Answer 64