Pharm Principles (325E1) Flashcards

1
Q

3 phases of drug action

A

every drug every time
1: pharmaceutic (only for oral)
2: pharmacokinetic (iv drugs enter here)
3: pharmacodynamic

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2
Q

Phases of drug action: pharmaceutic (1)

A

drug dissolves to be used and absorbed in blood and body (dissolution) all oral drugs and only occurs w/ oral drugs

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3
Q

Phases of drug action: pharmacokinetic (2)

A

drug moving through the body and what the body does to the body (4 processes: absorption, distribution, metabolism, excretion)

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4
Q

Phases of drug action: pharmacodynamic

A

what the drug does to the body (MOA, intended effect, therapeutic action)

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5
Q

pharmacokinetic (2): absorption

A

the drug goes into the small intestines and then into the blood

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6
Q

pharmacokinetic (2): distribution

A

drug has already been absorbed into the blood and now it leaves the blood stream and goes to the site of action and exerts it effort

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7
Q

pharmacokinetic (2): metabolism / biotransformation

A

after the drug has been excreted, it is broken down by liver to go from lipid soluble to water soluble so it can be removed from the body method by which drugs are inactivated

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8
Q

pharmacokinetic (2): excretion

A

kidneys excrete water soluble form of drug (some drugs can be excretede from liver)

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9
Q

drugs must have what type of solubility to pass through the cellular membrane

A

lipid soluble (water soluble need a transport mechanism to cross)

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10
Q

if we give an drug PO/orally, what does it have to go through

A

first pass effect

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11
Q

what drugs are 100% bioavailable

A

IV drugs (PO drugs have a varying of

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12
Q

PO meds bio availability

A

the amount of drug left after the first pass effect (ex: if first pass is 20%, then the drugs bio avail is 80%)

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13
Q

when would you expect to see a high first pass %

A

if a drug is taken in a high amount (dose) or is taken often

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14
Q

high first pass % would give what type of bio availability %

A

low

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15
Q

the first pass effect alters

A

the amount of a drug that is absorbed

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16
Q

first pass effect

A

PO meds that are absorbed in the SI have to go through the liver to be turned into its active form before they can enter circulation and this determines their bio availability

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17
Q

routes of absorption (ROA)

A

enteral
parenteral
topical

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18
Q

enteric coated (EC) meds

A

intended to break down in the small intestine and not the stomach (still goes through first pass)

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19
Q

ROA: enteral

A

by way of the GI tract (oral/gastric mucosa, SI, rectum aka po meds & rectal)

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20
Q

PO meds break down starts in the “” and are absorbed in the “” and it does or does not go through first pass?

A

stomach ; small intestine ; does

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21
Q

what routes of enteral meds do not go through first pass and why

A

SL, buccal and rectal bc all sites contain highly vascularized tissue

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22
Q

why can you not make a PO drug rectal

A

no first pass effect due to the bio availability so it by passes the liver

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23
Q

ROA: parenteral

A

SQ, IM, IV, intrathecal (into spinal canal), epidural (space around the spinal cord)

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24
Q

do parenteral drugs go through first pass effect

A

no

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25
Q

what route of parental drug is fastest

A

IV bc there are no barriers to absorption (they are often irreversible)

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26
Q

ROA: topical (transdermal)

A

application of meds to body surfaces, has a slower onset & more prolonged interaction

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27
Q

do topical drugs go through first pass effect

A

“not concerned with first pass effect because it will act very localized”

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28
Q

where does the best drug distribution occur

A

in areas that are highly vascularized w/ good blood flow (decreased blood flow = decreased distribution)

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29
Q

condition that decrease blood flow

A

peripheral vascular disease, abscesses, tumors

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30
Q

blood brain barrior

A

cells in the capillary wall in the brain with very tight junctions that prevent drug passages (prevents drugs from going to the brain as a preventive mechanism)

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31
Q

what drugs can’t pass the blood brain barrier

A

only drugs that have transport systems or are “extremely” lipid soluble

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32
Q

what drugs can pass the blood brain barrier

A

alcohol, glucose (the brains source of energy)

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33
Q

what is a main consideration when giving drugs to infants

A

the blood brain barrier is not fully developed so more drugs can pass through

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34
Q

protein binding effect

A

temporary storage of drug molecule that allows drug to be available for a longer period of time, drugs bind to albumin but can rapidly be unbound

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35
Q

what type of drug, bounded or unbounded, is considered active and free exert effects

A

unbound (free)

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36
Q

what is the goal of protein binding

A

maintain a steady free drug concentration “steady state”

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37
Q

what affects protein binding

A

the amount of protein in the blood

38
Q

what is the primary plasma protein

A

albumin (it circulates constantly)

39
Q

hypo albuminemia

A

malnutrition or liver disease more free drug is available for distribution to tissue site leading to possibility of overdose and drug toxicity

40
Q

example of protein binding: warfarin/coumadin

A

this is a blood thinner that is 97-99% protein bound so if a pt has low albumin a person is at greater risk for bleeding due to higher effect of drug exerted

41
Q

besides low albumin, what else is a risk factor for toxicity of protein bound drugs

A

if a person is taking multiple protein bound drugs at the same time bc all the drugs are fighting for the albumin in the body

42
Q

a drug goes through metabolism (biotransformed) and is inactivated, what is it now called

A

metabolite

43
Q

what is the major site for drug metabolism

A

the liver by cytochrome P-450 enzymes

44
Q

what organ(s) failure can lead to drug toxicity

A

the liver bc they don’t get metabolised, the kidneys bc the drug doesn’t get excreted

45
Q

how many drugs use the CYP450 system

A

about 1/2 of all drugs ; since so many use it, it creates drug - drug interactions

46
Q

clinical significance of CYP450 inhibitor

A

can be a substrate, inducer or inhibitor

47
Q

if a drug uses CYP450 system as a substrates

A

the drug uses the system for metabolism (it initiates the drug)

48
Q

if a drug uses CYP450 system as an inducer

A

the system increases the breakdown and elimination of the drug to lower the drugs therapeutic effect

49
Q

if a drug uses CYP450 system as an inhibitor

A

the system decreases the breakdown and elimination of the drug to increase the amount of drug in the body and increase the therapeutic effect risk for toxicity

50
Q

example of CYP450 inhibitor

A

grapefruit -> drinking or eating grapefruit with a CYP450 drug increases the amount of the drug in the body leading to toxicity

51
Q

teaching point for grapefruit consumption and medications

A

don’t take medications w/ grapefruit juice and avoid eating grapefruit or drinking it for 2-4 hours after taking me

52
Q

what is the major site of excretion

A

the kidney through gglomerular filtration, tubular secretion, and tubular reabsorption all need to be working for the drug to be excreted

53
Q

reabsorption from the kidneys

A

some drugs are reabsorbed through the kidney tubules, if low amounts of a drug is reabsorbed, need high dose to maintain levels

54
Q

what are the renal labs

A

BUN, creatinine, GFR (main one)

55
Q

what does half life determine

A

dosing of a drug and how often it should be given

56
Q

what process from phase 2 does half life effect

A

elimination (it takes 5 half lives for 97% of a drug to be eliminated)

57
Q

serum half life (T 1/2)

A

the time required for the serum concentration of a drug to decrease by 50%

58
Q

example for T 1/2: if half life is 1 week, how long will it take for the drug to be gone from the body

A

5 weeks

59
Q

how many half livees for a “steady state” to occur

A

4-5

60
Q

goal of steady state

A

when intake of a drug is equal to the amount of drug metabolized and excreted (the state when the BP meds will have BP always under control)

61
Q

around the clock dosing (ATC)

A

goal is to maintain 50% concentration in the body (how we treat pain and dose antibiotics)

62
Q

drug onset

A

time it takes for drug to elicit therapeutic response (latent period)

63
Q

drug peak

A

time it takes for drug to reach its maximum therapeutic effect (when 10mg of morphine feels like 10mg of morphine)

64
Q

drug duration

A

time drug concentration is sufficient to elicit a therapeutic response (consistent 5mg)

65
Q

how do drug create a response in phase 3

A

increase, decrease, replace, inhibit, destroy, protect, or irritate

66
Q

what are non desired effects of a drug

A

side effects (ex: metaproterenol is a broncho dilator so it dilates the bronchial passage but it also increases HR & palpitations beyond normal range)

67
Q

receptors

A

proteins located on cell surface that are chemicals (hormones or neurotransmitters) in the body that interact with drugs to produce effects (creates drug receptor complex)

68
Q

what does the drug receptor complex initiate

A

a physiochemical reaction by means of agonist (stimulates) or antagonist (inhibits)

69
Q

agonist

A

a drug that has the ability to initiate a desired therapeutic effect by binding to a receptor

70
Q

antagonsit

A

a drug that produces it action not be stimulating receptors but by preventing or blocking or inhibiting other natural substances (ligands) from binding and causing a response

71
Q

do all drugs responses involve receptors

A

no, some drugs act through simple physical or chemical interactions with small molecules (ex: antacids work by neutralizing gastric acidity through direct chemical interaction)

72
Q

therapeutic index

A

the measure of relative safety of a drug

73
Q

narrow therapeutic index (NTI)

A

a ratio of lowest concentration at which clinical toxicity commonly occurs (if safe range is 10, toxic at 10.1)

74
Q

black box warning

A

required by FDA for drugs that are especially dangerous (the strongest safety warning a drug can carry and still remain on the market)

75
Q

examples of NTI drugs

A

theophyllin, digoxin, phenobarital, lithium, coumadin

76
Q

where must the black box warning appear prominently

A

on the package insert, product label and any magazine or advertising

77
Q

med errors are a major cause of what

A

morbidity and mortality

78
Q

high alert medications

A

most likely to cause serious harm and death

79
Q

examples of high alert meds

A

insulin, heparin, opioids, IV KCL, neuromuscular blocking agents, chemo drugs

80
Q

what are the types of drug interactions

A

drug - drug (most concerning w/ NTI)
drug - food
drug - herb
drug - disease

81
Q

how to minimize drug interactions

A

lower # of drugs a person is on, reconcile meds, monitor

82
Q

drug interactions that increase therapeutic effect: additive effects

A

2 drugs taken w/ similar MOA (they become stronger together)

83
Q

drug interactions that increase therapeutic effect: synergism/potentiation

A

2 drugs w/ different MOA but result in a combined drug effect greater than that of either drug alone (still will become stronger together)

84
Q

drug interactions that increase therapeutic effect: activation

A

activation of drug - metabolizing enzymes in the liver which decreases metabolism rate of the drug

85
Q

drug interactions that increase therapeutic effect: displacement

A

displacement of one drug from plasma protein binding sties by a second drug which increases effect of displaced drug

86
Q

drug interactions that decrease therapeutic effect: antidote

A

drug given to a antagonize (stop) the toxic effects of another drug

87
Q

drug interactions that decrease therapeutic effect: decrease intestinal absorption

A

applied for PO meds bc some people cannot break down for effect

88
Q

drug interactions that decrease therapeutic effect: activation

A

activation of drug metabolizing enzymes in the liver -> enzymes inducers (get the drug out quicker)

89
Q

pharmacokinetic consequences in older adults

A

-decreased production of CYP 450 enzymes
-increase risk for drug interactions

90
Q

changes in older adults

A

-hepatic: drugs metabolize slower
-cardiac/circ: impaired, slows distri.
-GI: decreases absorption of PO meds
-Renal: drugs excreted less completely