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Pharmacology Midterm (edit) > Lecture 2 Part 2 > Flashcards

Lecture 2 Part 2 Flashcards

1
Q

how can agonists be divided?

A

into 2 classes based on the maximum pharmacological response that occurs when ALL RECEPTORS ARE OCCUPIED-

-partial agonist
-full agonist

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2
Q

true or false

partial agonists produce a lower response at full receptor occupancy than full agonists

A

true

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3
Q

true or false

emax is lower for full agonists than partial

A

false

emax is lower for partial agonists than full

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4
Q

partial agonists produce concentration-effect curves that resemble what?

A

resembles the concentration-effect curve of full agonist in the presence of an irreversible antagonist

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5
Q

______ experiments have demonstrated that partial agonists may occupy all receptor sites

A

Radioligand-binding experiments

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6
Q

what happens when partial agonists saturate all receptor sites

A

they still fail to produce a maximal response (compared to that of a full agonist)

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7
Q

TRUE OR FALSE

increasing concentration of partial agonist cannot displace a fixed conc of agonist from the receptor

A

FALSE - it can

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8
Q

true or false

partial agonists may occupy all receptor sites

A

true

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9
Q

in the presence of partial agonist, can emax be reached?

A

NO

partial agonists are “not as good” at activating the receptor

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10
Q

the response caused by a single concentration of full agonist ______with increasing concentrations of partial agonist

why?

A

decreases

the partial agonists are competing with the agonists to bind to the receptor. The partial agonist with increasing concentration, increasingly occupies the receptors and is “not as good” at activating them

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11
Q

true or false

all methods of antagonism involve interaction of drugs/endogenous molecules at a single type of receptor

A

FALSE

there are chemical antagonists and physiologic antagonists

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12
Q

explain chemical antagonists and give an example

A

one drug may antagonize the actions of another drug by binding to and inactivating the drug.

ex: heparin is an anticoagulant that is negatively charged.
PROTAMINE is positvely charged and can be used to clinically counteract the effects of heparin.

protamine antagonizes the effect of heparin by binding to it and making it unavailable for interaction with proteins involved in blood clot formation

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13
Q

what is a major side effect of heparin

A

excessive bleeding

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14
Q

what is the antidote to heparin

A

protamine - a chemical antagonist

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15
Q

antacids could be considered what kind of antagonist

A

chemical

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16
Q

physiologic antagonism takes advantage of _______ regulatory pathways

A

endogenous

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17
Q

many physiologic functions are controlled by what?
give an example

A

opposing regulatory pathways

ex: glucocorticoids increase blood sugar and the pancreas produces insulin to lower blood glucose levels (clinician could also administer insulin)

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18
Q

to oppose the hyperglycemic effects of a glucocorticoid hormone, the clinician must sometimes administer what? what is this an example of?

A

insulin

physiologic antagonism

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19
Q

GRADED dose response curves show……….

A

the effects on a continuous scale and the intensity of the effect is proportional to the dose

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20
Q

when choosing among drugs and determining the appropriate dose for a drug, what must be considered?

A

the drug’s POTENCY and MAXIMAL EFFECT

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21
Q

define potency

A

the concentration/dose of drug required to produce 50% of the drug’s maximal effect

-EC50/ED50

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22
Q

potency depends on what 2 things

A

the affinity of drug binding (KD)
the maximal response for that drug (efficacy)

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23
Q

potency depends on __ and ___

A

affinity (KD) and efficacy

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24
Q

define efficacy

A

the measure of an effect produced by a drug

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25
Q

what terms are most important to use when COMPARING DRUGS

A

potency and efficacy

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26
Q

_____ is determined by the maximal response of the drug

A

efficacy

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27
Q

when comparing the potency of drugs, what exactly are you comparing?

A

the EC50/ED50

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28
Q

what is a Quantal dose effect curve

A

basically just tells whether the desired effect occurred or it didn;t

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29
Q

explain how quantal/graded dose response curves can be used in different scenarios

A

graded dose response curves are limited in their application to clinical decision making bc they can’t be used if the pharmacological response is QUANTAL EVENT (either-or)
ie: prevention of convulsions, death

ALSO clinical releavance of graded dose response curve in a single patient may be limited in its application to other patients (the severity of the disease/responsiveness to the drug)

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30
Q

name 2 limitations of graded dose response curves

how can these problems be avoided?

A

-does not work for a quantal event (either/or) ie: prevention of convulsions, death

-clinical application – graded dose response curve for a single patient may not apply to all patients in that the severity of the disease and responsiveness to the drug may be different

can be avoided by determining the dose of drug required to produce an effect of specific magnitude in a LARGE NUMBER OF PATIENTS (or animals) and lpotting the cumulative frequency distribution of responders vs the log dose (GAUSSIAN NORMAL CURVE – how pts tend to respond to drugs)

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31
Q

________- may be used to generate information regarding the margin of safety

A

quantal dose-effect cirves

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32
Q

besides quantal dose effect curves, toxic effects of a drug on humans/animals can also be assessed by….

A

plotting the cumulative frequency distribution of responders vs log dose

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33
Q

in order for a drug to have a HIGH MARGIN OF SAFETY, the therapeutic effects should be observed at _______ doses than toxic effects

A

lower

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34
Q

true or false

therapeutic effects and toxic effects should overlap

A

false - should not

however, this is not always possible.

35
Q

true or false

graded dose response curves can be used to generate information regarding the margin of safety

A

FALSE - quantal dose-effect curves

36
Q

the margin of safety of a drug depends on……

A

ratio between ED50 and TD50

TD50/ED50

ideal to have a LARGE VALUE (meaning TD50 is high and ED50 is low)

37
Q

TRUE OR FALSE

BOTH graded and quantal dose effect curves provide information regarding the potency and selectivity of drugs

A

true

38
Q

the ____ curve indicates the maximal efficacy of a drug

A

graded dose response curve

39
Q

the ____ curve indicates the potential variability of responsiveness in patients

A

quantal dose-effect curve

40
Q

NO DRUG CAUSES A SINGLE, SPECIFIC EFFECT.

give 4 reasons for this

A

diversity of:

-receptors
-biochemical processes
-cell types, tissue types, and organs

DRUGS ARE SELECTIVE BUT NOT SPECIFIC

41
Q

drugs are ____ but not _____

A

selective but not specific

meaning that a drug is selective for a general type of receptor but not specific to one specific receptor

42
Q

as mentioned, no drug causes a single, specific effect

how do you deal with this?

A

carefully manage the dose to avoid toxicity, along with careful monitoring of the patient

OR not administering the drug at all and using an alternate

43
Q

in some instances, a drug may be clearly necessary and beneficial but produces unacceptable toxicity at the doses which bring this benefit.

what can be done?

A

the addition of another drug may be possible

44
Q

give a specific example of a drug that is clearly necessary and beneficial but produces a certain toxicity/side effect at normal doses

A

prazosin - an antihypertensive.
a1-adrenergic receptor antagonist acts on receptors in vascular smooth muscle to reduce BP.

as a consequence, patients may suffer postural hypotension (drop in BP when you stand up - hardest for tall ppl)

45
Q

true or false

when drugs act on their receptor, they can produce both a toxic and therapeutic effect mediated by the same receptor-effector mechanism

A

true - prazosin causes a drop in BP which is good, but also causes postural hypotension

46
Q

what are some therapeutic strategies to avoid drug toxicities

A

-drug should be administered at the lowest possible dose that produces an acceptable benefit

-adjunctive (another) drug that acts through a different receptor mechanism may allow the dose of the 1st drug to be lowered, which would decrease its toxicity

-the drug can be specifically placed in parts of the body where it will have reduced toxicity (infusing the drug directly into the tumor)

47
Q

the drug should always be administered at what dose

A

the lowest possible dose that produces acceptable benefit

48
Q

true or false

individuals may vary in their responsiveness to a drug

A

true

49
Q

individuals may vary in responsiveness to a drug.

name 6 different responses

A

idiosyncratic
hypo reactive
hyper reactive
hypersensitivity
tolerance
tachyphylaxis

50
Q

idiosyncratic response

A

an unusual response that is rarely observed in patients

51
Q

hypo reactive response

A

a drug effect that is smaller than expected

52
Q

hyper reactive response

A

a drug effect that is larger than expected

53
Q

hyper sensitivity response

A

an allergic reaction to the drug

54
Q

tolerance response

A

responsiveness decreases as a result of continued drug administration (desensitization)

55
Q

tachyphylaxis response

A

responsiveness diminishes rapidly after administration of the drug

56
Q

there were 6 different responses listed in which individuals can vary in their response to a drug.

when these effects occur, what should be done?

A

the dose should be modified or the drug itself should be changed

57
Q

name 5 factors to be considered in variable drug responses

A

age
body size
sex
disease state
simultaneous administration of other drugs

58
Q

explain how body size can cause varying drug responses

A

a high body weight may affect the distribution of the drug due to high fat content

59
Q

beneficial and toxic effects can be mediated by the same receptor-effector mechanism to the SAME TISSUE or…..

A

-by identical receptors that affect 2 DIFFERENT TISSUES or by different effector pathways – toxic in 1 tissue and therapeutic in another

-by DIFFERENT TYPES OF RECEPTORS

60
Q

give a specific example of when a beneficial or toxic effect is mediated by an identical receptor but in different tissues or effector pathways

A

digitalis (digoxin) is therapeutic in cardiac contractility but has toxic effects in the GI and eye

61
Q

new drugs are emerging with improved_____
explain this

A

receptor selectivity

a drug can bind to 1 receptor to produce response 1 and bind to another receptor to produce response 2

ex: alpha and beta adrenergic agonists

62
Q

almost all of the several thousand drugs currently available can e arranged in about ____ groups based on what?

A

70 groups

based on structure activity relationships

63
Q

define structure activity relationships

A

understanding the relationship between drug structures and biological activities

-forms the basis of RATIONAL DRUG DESIGN

64
Q

what forms the basis of rational drug design

A

structure activity relationships

65
Q

many of the drugs within each group are very similar in what?

A

pharmacodynamic actions and often in pharmacokinetic properties as well

66
Q

for most drug groups, what can be identified that typifies the most IMPORTANT CHARACTERISITICS of that group?

A

one or more prototype drugs

67
Q

a patent expires how long after filing an NDA?

A

20 years after filing

68
Q

how many types of FDA applications are there? name them

A

5 types:

-IND (investigational new drug)
-NDA (new drug application)
-ANDA (abbreviated NDA)
-OTC
-BLA (biologic license application)

69
Q

how many phases of study are there? name them in order

A

in vitro studies
animal testing
clinical testing
marketing

70
Q

how long are in vitro studies

A

0-2 years

71
Q

how long is animal testing (in vivo)

A

2-4 years after discovering drug

72
Q

how long is clinical testing

A

4-8 years after discovering drug

73
Q

how long is NDA

A

8-9 years after discovering the drug (1 year)

74
Q

how long is postmarketing surveillance

A

9-20 years after discovering drug

75
Q

what leads to finding the “lead compound” which undergoes in vitro studies?

A

biologic products
chemical synthesis and optimization

76
Q

what is discovered in animal testing (in vivo)

A

efficacy
selectivity
mechanism

77
Q

how many phases of clinical testing are there?
name what is looked for in each

A

phases 1 -4

phase 1 - safety (pharmacokinetics)

phase 2 - effficacy (does it work)

phase 3 - efficacy - but DOUBLE BLIND

phase 4 - postmarketing surveillance

78
Q

name the # of pts in each phase of clinical testing

A

phase 1: 20-100

phase 2: 100-200

phase 3: 1000-6000

phase 4: general public

79
Q

throughout the entirety of clinical testing, what is assessed

A

metabolism and safety assessment

80
Q

biological products include a wide range of products such as…….

what FDA application is required?

A

BLA - biologic license application

vaccines
blood/blood components
somatic cells
allergenics
gene therapy
tissues
recombinant therapeutic proteins

81
Q

what are orphan drugs

A

for the treatment of rare disease – those that affect less than 200k in the US

82
Q

explain the pathway that the FDA has created for the approval of orphan drugs

A

orphan drug destination program – provides ORPHAN STATUS to drugs and biologics which are those intended for the safe and effective treatment, diagnosis, or prevention of rare diseases/disorders that affect FEWER THAN 200,000 ppl in the US or affect more than 200k but are not expected

83
Q
A

Pharmacology Midterm (edit) (12 decks)

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