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Pharm & Ototoxicity > Exam 1 (Lectures 5, 6, & 7) > Flashcards

Exam 1 (Lectures 5, 6, & 7) Flashcards

1
Q

what is pharmacodynamics

A

study of drug effects on the body
what meds do to our body and how they do it

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2
Q

pharmacologic effect

A

occurs due to change in the function of the cell/organism

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3
Q

drugs do not elicit new functions

A

true
they produce the same action as body’s own chemicals
block the normal action of body’s own chemicals

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4
Q

what do drugs do

A

drugs do not elicit new functions
they produce the same action as body’s own chemicals
block the normal action of body’s own chemicals

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5
Q

what brings about a drug action?

A

ligands (extracellular molecules like antibody, hormones, NT or drugs, that binds to receptor) bind to receptor at cellular level

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6
Q

what are receptors

A

specialized target molecule that binds to a drug & mediates its pharmacological action
once a drug binds to receptor, response can result from the binding action

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7
Q

biological response

A

formation of drug-receptor complex

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8
Q

where are receptors found

A

present either - on the outside of the membrane, inside of the membrane, spanning both sides of cell membrane

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9
Q

receptor sites on a single cell can

A

metabolize or regulate enzymes, proteins or glycoproteins associated with cell transport mechanisms, structural and functional parts of the membrane, & nucleic acids

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10
Q

what is a free receptor

A

unoccupied receptors

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11
Q

what is an occupied receptor

A

reversibly bound to a drug receptor

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12
Q

explain what happens when enough receptors are bound

A

when enough are bound (occupied by a substance) the combined effect of the filled receptors is strong enough to cause the max response that that cell can produce
when this happens in many cells, the effect is apparent in the organ and/or the PT

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13
Q

drugs react by

A

Covalent, ionic, hydrogen, hydrophobic, or Van der Waals bonding to produce a definable pharmacological response

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14
Q

which bonding in drugs are the most common

A

hydrogen & ionic are the most common

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15
Q

what determines how strong a drug sticks to a receptor and how it attaches to it

A

drugs chemical structure determines how strong a drug sticks to a receptor and how it attaches to it

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16
Q

When a drug binds to its receptor, it starts a series of steps that lead to either

A

a positive effect or an unwanted side effect.

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17
Q

If you increase the amount of the drug (ligand) or the number of receptors, the effect of the drug can also increase.

A

true

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18
Q

what is the lock in the model

A

enzyme (receptor)

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19
Q

what is the key in the model

A

substrate (drug molecule/ligand)

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20
Q

what is the lock and key method

A

only the correct key (drug) fits into the key hole (active site) of the lock (receptor)
believed that body has natural ligand (key) for every receptor

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21
Q

what is the induced fit model

A

not all reactions are explained by lock and key theory
this model assumes the substrate (drug molecule) plays a role in determining the final shape of the receptor
receptor is partially flexible)

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22
Q

what does the induced fit model explain

A

certain compounds can bind to the receptor but doesn’t cause a reaction because the receptor is distorted too much
other molecules are too small to cause a reaction
only the proper substrate is able to fit into the active part of the receptor in order for it to work correctly and produce the desired effect

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23
Q

differences between the lock and key model & induced-fit model

A

Lock and Key Model:
Concept: In this model, the receptor and the molecule (often called the ligand) have specific shapes that fit together perfectly, like a key fitting into a lock. The receptor’s shape is fixed, and only a molecule with the exact matching shape can bind to it.
Analogy: Imagine a lock (the receptor) that only a specific key (the ligand) can open.

Induced Fit Model:
Concept: In this model, the receptor is more flexible. When the molecule approaches, the receptor adjusts its shape slightly to better fit the molecule. This change helps the binding to be more effective.
Analogy: Imagine a glove (the receptor) that changes shape slightly to fit the hand (the ligand) as you put it on.

Key Difference:
The Lock and Key Model suggests that both the receptor and the molecule have fixed shapes that fit together perfectly from the start.
The Induced Fit Model suggests that the receptor can change its shape to accommodate the molecule, making the binding process more adaptable.

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24
Q

what are G proteins

A

involved in transmitting signals from variety of stimuli outside the cell to its interior important processes

funtion: activates production of second messengers (signaling molecules) that convey input provided by the first messenger to cytoplasmic effectors

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25
Q

bind to guanine nucleotides GDP (guanine-dinucleotide proteins) and GTP (guanine-trinucleotide proteins

A

g proteins

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26
Q

family of proteins that act as molecular switches inside cells

A

g proteins

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27
Q

most abundant class of cell receptors in the body

A

g proteins

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28
Q

describe the production of second messengers when activated by g proteins

A

When a first messenger (like a hormone or neurotransmitter) binds to a receptor, it triggers the production of second messengers inside the cell. These second messengers then carry the signal from the first messenger to other parts of the cell (cytoplasmic effectors) to create the desired response.

activity is regulated by factors that control their ability to bind and hydrolyze guanosine triphosphate (GTP) to guanosine diphosphate (GDP)

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29
Q

larger group of g protein enzymes

A

GTPases

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30
Q

what are transmembrane ion channels

A

cellular functions require passage of ions and other molecules across the membrane and specialized transmembrane channels (ion channels) regulate this process

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31
Q

what is the function of the transmembrane ion channels

A

The function of ion channels is diverse, including fundamental roles in regulating the flow of ions across cell membranes, maintaining the cell’s electrical charge, controlling cell signaling, enabling muscle contractions, and supporting nerve impulse transmission

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32
Q

what is cell signaling

A

process by which cells communicate with each other and respond to their environment. This communication occurs through a series of molecular events that involve signaling molecules, receptors, etc.

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33
Q

all organisms have signal systems that warn presence of pathogens that leads to a protective response

A

true

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34
Q

where do signals come from for the cell

A

signals come from light, heat, chemicals (NTs), water, odors, touch and/or sound
cells can receive and interpret signals from their environment and from other cells like signals for cell division, differentiation, and apoptosis

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35
Q

what are cell responses to a signal

A

ion channels open or close
intracellular second messenger is formed
gene expression of cell is altered
initiation or alterations in cell growth and differentiation

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36
Q

how does a cell respond to a drug

A

cell function or structure change is the cell’s response to the drug
cell response can be the same, greater or less than the normal endogenous response

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37
Q

what happens to get a cell to change function or structure

A

ligand attaches to a spot on a receptor protein causing the receptor to change shape which is passed down along the inside of the cell membrane causing changes in how that cell functions or is structured

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38
Q

what is confirmational change in a cel

A

when a receptor is actived or blocked the cell changes shape and affects how it works or looks

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39
Q

what causes cell signaling to occur

A

agonist attaches to receptor
causing g protein activation
which causes second messenger
which causes cell signaling activation

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40
Q

what are cognate receptors

A

two biomolecules that typically interact

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41
Q

pharmacological properties of drugs are based on

A

the effects they have on the state of their cognate receptors (two biomolecules that typically interact)

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42
Q

what is an agonist

A

drug that after receptor binding results in active conformation
ligands that activate receptors

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43
Q

the _______ the bond bw drug & receptor the more likely it will have the intended effect

A

stronger

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44
Q

drugs with a weak attraction to a specific receptor attaches to it more readily than others

A

false
strong

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45
Q

examples of agonists

A

all NT that are at their respective sites - acetylcholine (ACh - excitatory)), Gamma-amino butryic acid (GABA - inhibitory), glutamate (excitatory), histamine, norepinephrine (NE), Seratonin 5 hydroxytryptamine (5-HT)

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46
Q

excitatory agonists

A

acetylcholine & glutamate at their respective sites

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47
Q

although all NT are agonists at their respective receptor sites there are drugs that are agonists & antagonists to NT actions

A

true

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48
Q

examples of drugs that are agonists & antagonists to NT actions

A

seratonin produced in the brain & stomach
triptans - drug that mimics seratonin effects = agonists at 5-HT1 receptor site which is mainstay of migraine treatment

serotonin antagonist drugs can block the release - used to prevent/relieve nausea and vomiting from chemotherapy and after surgery from effects of anesthesia

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49
Q

what is an antagonist

A

drug that favors inactive conformation after receptor binding
inhibit action of natural agonists at receptor sites

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50
Q

you can have an antagonist effect without an agonist

A

false
without an agonists there is no effect of an antagonist

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51
Q

inhibit actions

A

antagonists

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52
Q

activates receptors

A

agonists

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53
Q

examples of antagonists

A

Beta-receptor antagonists or beta-blockers are drugs that affect heart rate and blood pressure by blocking the effect of norepinephrine (a natural agonist) at its respective binding site on beta receptors

Med used to treat vertigo or Meniere’s
ACh receptor antagonist scopolamine (Transderm scop patch) and meclizine (antivert)
Histamine receptor antagonist or “antihistamine,” diphenhydramine (Benadryl)

some drugs like promethazine (Phenergan -1st generation histamine H1 antagonist) can block multiple neurotransmitters
It exhibits an anticholinergic, antihistamine, and antidopaminergic properties all in one product

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54
Q

what can be targets of drug action

A

enzymes & proteins

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55
Q

examples of enzymes & proteins can be targets of drug action

A

ibuprofen, the non-steroidal anti-inflammatory drug (NSAID) inhibits the enzyme cyclooxygenase
Cyclooxygenase is needed to create the inflammatory prostaglandins that can form secondary to muscle injury

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56
Q

Another drug that inhibits prostaglandin formation is acetylsalicylic acid (Aspirin), one of the first NSAIDs discovered and brought to market

A

true

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57
Q

what are the antagonist classifications

A

antagonist
non receptor agonists or receptor agonists
non receptor - chemical & physiological
receptor - active site bonding & allosteric binding
active - reversible (competitive) or irreversible (noncompetitive active)
allosteric - reversible & irreversible (noncompetitive allosteric)

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58
Q

Antagonists can be categorized based on whether they bind to a site on the receptor for agonist (receptor antagonists) or interrupt agonist–receptor signaling by other means (nonreceptor antagonists).

A

true

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59
Q

Receptor antagonists can bind either to the

A

active receptor sites (prevents binding of an agonist to the receptor) and allosteric (not active) (prevents conformational change required for receptor activation

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60
Q

are receptor antagonists reversible

A

yes

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61
Q

Agonist (active) site receptor antagonists prevent the agonist from binding to the receptor. If the antagonist competes with the ligand for agonist site binding, it is termed a competitive antagonist; high concentrations of agonist are able to overcome competitive antagonism

A
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62
Q

allosteric sites

A

(not active) prevents the conformational change required for receptor activation

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63
Q

a receptor antagonist can bind to

A

active site or allosteric site

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64
Q

what does an active receptor site do

A

prevents binding of an agonist to the receptor

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65
Q

what does an allosteric site do

A

prevents confirmational change required for receptor activation

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66
Q

Receptor antagonists can be

A

reversible or irreversible

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67
Q

reversible receptor antagonists

A

bind to a receptor site reversibly

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68
Q

irreversible receptor antagonists

A

binding of a receptor site is irreversible

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69
Q

Both agonist and antagonist compete for the same receptor sites
If an antagonist binds first, it prevents the agonist from producing its effect

A

true

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70
Q

what types of binding can occur with antagonists

A

competitive or non competitive

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71
Q

what is a competitive antagonist

A

Bind reversibly to the same active site on the receptor as the agonist. Their presence competes with the agonist for binding. - remains in inactive form

binding is reversible -administering additional agonist displaces the antagonist from the receptor, allowing the agonist to produce its effectf

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72
Q

what is a non-competitive antagonist

A

can bind to either the active or the allosteric (non-active) receptor site
Noncompetitive antagonist bind irreversibly often through covalent bonding
They cannot be displaced even with high agonist concentration

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73
Q

what is the therapeutic window

A

range of doses (concentrations) of a drug that elicit a therapeutic response without unacceptable adverse effects (toxicity)

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74
Q

what happens when a drug has a small window

A

plasma drug levels monitored closely to keep effective dosage without becoming toxic

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75
Q

what is therapeutic index (TI)

A

TW quantified by TI, aka therapeutic ratio
TI = TD50 ÷ ED50

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76
Q

what is TD 50

A

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

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77
Q

what is ED50

A

Drug dose that is therapeutically effective in 50% of the population

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78
Q

What is a large TI

A

large (wide) TW

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79
Q

what is a small TI

A

small (narrow) TW

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80
Q

what is a dose-response relationshi[

A

Pharmacodynamics of a drug can be quantified by the relationship between the dose (concentration) of a drug and the organism’s (patient’s) response

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81
Q

two types of dose response relationships

A

graded & quantal

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82
Q

When a drug exerts an effect on a biologic system, the effect can be quantified according to the dose (how much) of the drug is given compared against the intensity (magnitude) of the effect

A

true

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83
Q

what is the graded dose response

A

describes the effect of various drug doses on an individual

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84
Q

what are the two parameters of graded dose response

A

potency of a drug (EC50) & efficacy (EC max) of a drug

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85
Q

what is EC50

A

potency

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86
Q

what is ECmax

A

efficacy

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87
Q

what is the potency of a rug

A

concentration which the drug elicits 50% of its maximal response
potency = affinity of a drug to its receptor

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88
Q

what is the efficacy of a drug

A

maximal response produced by a drug
efficacy = related to receptor occupancy by drug molecules

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89
Q

give an example of potency and efficacy

A

Demerol and Morphine are similar in efficacy
Both results in all receptors being occupied by the drug
they differ in potency
If 100 mg of Demerol is required to relieve severe pain
Then 10 mg of morphine is required to relieve the same severe pain

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90
Q

what is quantal dose response

A

describes effect of various drug doses on a population
describes concentrations of a drug that produce a given effect in a population
reponses = present/not present

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91
Q

what is the goal of quantal dose response

A

generalize the result to a population rather than examine graded effects of drug doses on an individual

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92
Q

Population responses that can be examined using quantal-dose response relationship include

A

Effectiveness (therapeutic effect)
Toxicity (toxic effects)
Lethality (lethal dose)

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93
Q

The doses that produce these responses in 50% (median) of the population, are known respectively as

A

median effective dose ED50
median toxic dose TD50
median lethal dose LD50

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94
Q

study of drug effects on the body

A

pharmacodynamics

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95
Q

can only bring about a pharmacological effect on the cells if it can attach to specific receptors that are either on the cell membrane or in the cell

A

drugs/ligands

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96
Q

Drugs can either cause

A

The same action as a natural ligand on cell receptors – agonists or
Stop the effect of a natural ligand on cell receptors - antagonists

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97
Q

The same action as a natural ligand on cell receptors

A

agonists

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98
Q

Stop the effect of a natural ligand on cell receptors

A

antagonists

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99
Q

adding more agonists will break the cell receptor–drug binding

A

competitive antagonists

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100
Q

will not break the cell receptor-drug binding even if more of the drug is added

A

noncompetative antagonists

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101
Q

Poisons act in this manner where the cell receptor–drug binding is generally irreversible

A

noncompetitive antagonists

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102
Q

what is the therapeutic window/index

A

range of doses that will elicit a therapeutic response without toxicity

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103
Q

Drug dose determines whether a drug will be

A

Effective for 50% of the population (ED50)
Toxic for 50% of the population (TD50)
Lethal for 50% of the population (LD50)

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104
Q

related to affinity of a drug to its receptor

A

Potency (EC50 )

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105
Q

______ the potency, ______ amounts of the drug needed to cause action

A

Higher
less

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106
Q

refers to the maximal response produced by a drug and is related to receptor occupancy by drug molecules

A

Efficacy (ECmax)

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107
Q

measures population response to drugs

A

quantal dose response

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108
Q

measures individual responses to drugs

A

graded-dose response

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109
Q

what is pharmacokinetics

A

study of how drugs are acted upon by phsiological functions
what the body does with the drug

110
Q

overview of pharmacokinetics

A

drug enters body circulates through it, changed by the body and then leaves it

111
Q

Pharmacological therapy will fail in clinical trials when

A

drug cannot reach the target organ(s)
concentrations are not sufficient enough to cause an effect

112
Q

what makes a drug successful

A

Characteristics in the body that protect from foreign bodies & toxins also limit modern drugs to combat pathoogical processes within a PT

successful drugs have to cross the physiological barriers in the body that are in place to limit access to foreign substances (viruses, bacterial and environmental toxins)

113
Q

4 steps of drug movement

A

absorption
distribution
metabolism (biotransformation)
excretion (elimination)

114
Q

what affects free drug that reaches the target receptor site

A

ADME

115
Q

only a fraction that successfully binds to the target site will exert its effect

A

true

116
Q

metabolism of the drug produces

A

active and inactive metabolites (drug products after metabolism)

117
Q

exert an effect on either the drug target receptor or other receptors

A

active drug product

118
Q

prerequisite for establishing optimal plasma drug levels for therapeutic drug actions

A

absorption

119
Q

what happens in drug absorption

A

can occur by a number of mechanisms designed to either exploit or breach the body’s physiologic barriers

different drug routes affect how it is absorbed

first pass metabolism

120
Q

Physiological barriers to drug movementf

A

cell membrane
BBB
BLB
BPB

121
Q

factors affecting the rate of drug movement across the membrane

A

solubility of the drug
route of administration

122
Q

what is solubility of a drug

A

the ability of it to dissolve in a solvent (liquid - water, bodily fluids like blood or stomach acid)
drugs in solutions more rapidly absorb than insoluble ones

123
Q

closer to the site of administration is to a blood vessel the faster a drug can be absorbed

A

true

124
Q

what molecules pass the cell membrane easily

A

nonpolar molecule (steroids)

125
Q

what are not passed easily through the membrane

A

most drugs & polar molecules - larger

126
Q

A polar (water soluble) molecule has a partial

A

+ve charge in one part of the molecule and complementary –ve charge in another part

127
Q

factors affecting drug’s passing ability across

A

lipid solubility
degree of ionization (charge)
molecular size
drug shape

128
Q

describe lipid solubility & membrane

A

more lipid soluble drug = easier crossing because they are water hating

129
Q

what drug molecules can generally pass through easily

A

hydrophobic

130
Q

can charge molecules cross the membrane?

A

charged molecules cannot cross (mus use pores/channels), Hydrophobic drug molecules can generally pass through easily

131
Q

what size can pass through the membrane

A

smaller = easier & larger = harder

132
Q

what drug shape can pass through the membrane

A

shape shifters can go through easier (induced-fit model)

133
Q

well insulated from foreign substances

A

CNS (also the testes and cochlea

134
Q

what is the BBB

A

selective barrier, separates circulating blood from brain extracellular fluid in the CNS
made by capillary endothelial cells connected by tight junctions & astrocytes (CNS supporting cells)
allows passing of water, some gases, lipid soluble substances by passive diffusion
allos selective transport of molecules like glucose amino acids crucial to neural function
can prevent entry of potential neurotoxins by way of an active transport (requires energy) mechanism

135
Q

BBB and prevention of drugs

A

prevents diffusion of most drugs from systemic to cerebral circulation

drugs designed for CNS are hydrophobic to easily pass biological membrane or use existing facilitative/active transport systems

Such drugs can be administered through intrathecal infusion (injected directly into the CSF)

136
Q

The intrathecal route is useful for single or limited doses and to treat meningitis or CNS cancers

A

true

137
Q

is intrathecal route practical for drugs that need to be taken on a more regular/daily basis

A

no

138
Q

what is the BLB

A

homeostatic mechanism protecting IE

139
Q

how can drugs affect BLB

A

Small molecular weight molecules can enter the perilymph in a dose and time dependent manner
Several ototoxic drugs and bacteria can cross the BLB and enter the perilymph
The rate of elimination from perilymph is much slower than that from serum

140
Q

Disruption of BLB can disrupt

A

ion transport system of the lateral cochlear wall, lead to disturbances of inner ear homeostasis, resulting in functional disruption of the auditory system

141
Q

what is the BPB

A

serves as a barrier between maternal and fetal circulation and protects the fetus from harmful agents

142
Q

what molecules can pass the BPB

A

antigens & antibodies cross both ways
small molecules can cross the placenta barrier

143
Q

examples of small molecules that can pass the placenta barrier

A

Many viruses, including cytomegalovirus (CMV), rubella (German measles), varicella-zoster (chicken pox), measles, HIV (AIDS), Zika, and poliovirus can cross the placenta
all of these viruses can potentially cause congenital deafness/HL

144
Q

what doesn’t cross BPB

A

Bacteria & other protozoa usually don’t cross
but treponema palladium (syphilis) and toxoplasma gondii (toxoplasmosis) that can cause congenital hearing loss

145
Q

is BPB a strong barrier for drugs

A

no
most can cross easily with non-ionized & lipid-soluble drugs crossing the easiest

146
Q

what allow or prevent drug movement in the body

A

physiological barriers

147
Q

what are the drug administration routes

A

enteral
topical
parenteral

148
Q

what is the enteral route

A

drug given directly into the gastrointestinal tract; non-enteral routes do not go through first-pass metabolism by the liver

oral & rectal administrion
simplest route

149
Q

benefits of enteral route

A

easy self administration, portable, less likely for systemic infections unlike parenteral route

150
Q

disadvantages of enteral route

A

exposes drug to harsh environments
lipid soluble drugs pass through GI tract the easiest
food in stomach can alter absorption rate
pH of stomach and drug can interfere with absorption
other drugs in stomach can cause drug interaction (in oral route)
drugs pass through first-pass metabolism in liver

151
Q

what is the first pass metabolism

A

only impact oral drugs & happens in the liver
pass from GI tract to portal veins to enter liver before the systemic circulation
protects from the effect of ingested toxins - detoxified in the liver
drugs enduring this need the right dosage to make sure the effective concentration happens on the target organs due to some inactivation in the liver

152
Q

process of first pass metabolism

A

When a drug is taken orally, it is absorbed through the lining of the stomach or intestines into the portal vein, which carries blood from the GI tract to the liver.
Liver Metabolism: Upon reaching the liver, enzymes, particularly those from the cytochrome P450 family, metabolize the drug. During this process, a portion of the drug may be inactivated or converted into metabolites, some of which might be active, while others are not.
Reduced Bioavailability: After passing through the liver, only a fraction of the original dose may reach the systemic circulation. This phenomenon reduces the bioavailability of the drug—the proportion of the drug that reaches the bloodstream in its active form.

153
Q

describe the topical route

A

drug applied to the surface of the body
transdermal - skin patches or ointments
otic - ear drops
nasal - nose drops
ophthalmic - eye drops

154
Q

describe the parenteral route

A

drug given in other routes than above
drug bypasses GI tract & its barriers
usually injectable drugs using syringes & needles

155
Q

advantages of parenteral

A

availability (IV drug is immediate in circulation, IM/SC has slower entry but faster than enteral), fast onset of drug action (IV - 15 to 30 ms; IM/SC - 3 to 5 mins) & if bioavailability is 100% the drug reaching system is the same for all routes parenteral & non-IV parental routes take longer for drug to reach peak values in circulation, useful route for drugs not absorbed by gut or too irritating (chemotherapeutic drugs), IV delivery is more controlled, one injection lasts for days/months, IV route delivers continuous meds (saline, pain meds, antibiotics etc.), & useful when PT unable to take med through GI (unconscious/coma, ER, before/after surgery)

156
Q

disadvantages of parenteral route

A

higher addiction risk due to rapid onset action, not all PTs can administer injections (belonephobia - fear of needles & injections), risk of hepatitis, HIV, etc w/ shared needles, most dangerous route (bypasses all natural defenses including BBB if given intrathecally, exposing PT to death due to adverse rxns or health problems like HIV, hepatitis, abscess, infections), fatal air bubbles, strict sterile environment, costs more (requires trained/skilled personnel)

157
Q

examples of perenteral route administration

A

inhalation, intradermal, intravenous, intrarterial, intramuscular, intraosseous, sublingual (enters venous circulation), intrathecal (injected into the spinal canal/subarachnoid space), & intraperitoneal (injected into the peritoneum),

158
Q

what is bioavailability

A

subcategory of absorption; a fraction of administered drug that reaches systemic circulation
how much of the drug you took and how much of it is available

159
Q

bioavailability equation

A

Bioavailability = Quantity of drug reaching systemic circulation ÷ Quantity of drug administered

160
Q

bioavailability of IV drugs

A

IV drugs injected into the systemic circulation = generally 1 (max) bioavailability

161
Q

bioavailability of oral drugs

A

oral drugs = <1 bioavailability

162
Q

what is bioavailability dependent on

A

route of administration, the chemical form of drug & PT factors (GI enzymes, pH and hepatic metabolism

163
Q

why is bioavailability important in generic drugs

A

these drugs have the same molecular structure but concentration and route of administration may differ

164
Q

FDA mandates generic has to have _____% of the bioavailability of the parent compound

A

90

165
Q

how are oil soluble drugs administered

A

subcutaneous or IM

166
Q

drugs able to dissolve in water-based solutions at pH levels found in the body can be administered

A

orally

167
Q

what is drug distribution

A

after absorption of the drug from the site of administration, its distributed to site of action primarily by circulatory system (blood plasma) and minor from the lymphatic system
after absorption from the site of administration, drug utilizes the body’s distribution system (blood & lymphatic vessels) to reach the target in appropriate concentrations

168
Q

therapeutic drug levels are determine from the concentration of it in the plasma

A

measuring in the target organ is hard to measure
correlates well with drug effect on the target site

169
Q

what has the most blood flow

A

liver & kidneys

170
Q

what affects drug concentration in the plasma

A

drug distribution in various tissues and compartments and blood flow variability bw different organs

171
Q

Drug occurs in two forms in the blood

A

bound to plasma proteins (common is albumin)
free or unbound drug (uncoupled from the protein) - active part of the drug

172
Q

waht is the active part of the drug

A

free (unbound) drug

173
Q

what is the car analogy

A

you sittin in the car, car going on the highway
you are the drug, car is the protein, highway is the blood
once the car and you go to the destination you decouple from the car (cannot bring car into the classroom)
if you didnt want to get out of the car, you wouldnt get
one that leaves the car (protein) unbound = bring about the change
one that stays in the car (protein) bound = no action brought about
10 molecules are now unbound so now they do the same thing and as they do their thing 10 more get unbound
not all of them get unbound

174
Q

how much of free drug is available based on

A

chemicals in body and chemicals in the drug

175
Q

What is Protein Binding?

A

When a drug enters your bloodstream, some of it attaches to proteins like albumin, which are floating in your blood. This is called “protein binding.” Think of it as a drug hitching a ride on a protein.

176
Q

What Happens When a Drug Binds to Proteins?

A

If a drug is bound to a protein, it stays in the blood and cannot move into other parts of the body (like tissues or organs) to do its job. The drug is essentially “stuck” in the bloodstream.

177
Q

What About Drugs That Don’t Bind Much to Proteins?

A

Drugs that don’t bind strongly to these proteins (like Drug A) can easily leave the bloodstream and spread into different parts of the body. This allows them to quickly reach their target and start working. However, they also get eliminated from the body faster because they are free to move to organs that clear drugs out of your system (like the liver or kidneys).
Examples: Acetaminophen (Tylenol) and nicotine.

178
Q

Drugs That Bind Strongly to Proteins:

A

Some drugs (like Drug B) bind very strongly to proteins in the blood. Because they are mostly bound, only a small portion of the drug is free to move out of the bloodstream and into the tissues where it needs to work. This means that to get enough of the drug into the tissues, you need a higher total amount of the drug in your blood.
Examples: Naproxen (a pain reliever) and warfarin (a blood thinner).

179
Q

Easily moves into tissues, works quickly, and is cleared out fast. You don’t need much of it in your blood.

A

low protein binding drug a

180
Q

Stays mostly in the blood, needs a higher amount to get enough of it into tissues, and is cleared out more slowly.

A

high protein binding
drug b

181
Q

what is drug metabolism

A

process which biochemical reactions alter within the body
aka drug biotransformation
breaks down the drug to be excreted from the body

182
Q

reactions convert lipid-soluble drugs to water soluble metabolites so the drugs can more easily be excreted by the kidneys

A

true

183
Q

_____ contains greatest quantity and diversity of metabolic enzymes

A

liver

184
Q

majority of drug metabolism happens in the

A

liver

185
Q

other drug metabolism happens in

A

kidneys, lungs, nerves, skin, plasma & GI tract

186
Q

biotransformation reactions are classified as

A

Oxidation/Reduction or Phase I
Conjugation/Hydrolysis or Phase II reactions

187
Q

what is phase I

A

modifies chemical structure of a drug through oxidation reduction & liver has enzymes to facilitate these rxns

188
Q

what is the most common pathway in the liver

A

Cytochrome P450 system or CYP enzymes

189
Q

primary machine for metabolizing drug

A

cyp enzymes

190
Q

how much in your liver determine how fast drug breaks down & is removed

A

true
cyp enzymes

191
Q

more CYP =

A

faster drug metabolism

192
Q

less CYP =

A

slower drug metabolism

193
Q

mediates oxidative reactions

A

Cytochrome P450 system or CYP enzymes

194
Q

the specific set of CYP enzymes a person has in their livers affects

A

how fast they can break down and process drugs - amount CYP

195
Q

these enzymes are involved in metabolizing about 75% of all drugs used today

A

Cytochrome P450 system or CYP enzymes

196
Q

If cytochrome P450 liver enzymes (CYP enzymes) are induced, it

A

if you increase the enzyme you increase metabolism (faster break down) so the drug leaves the body faster - inverse effects = induced (increasing the rate of metabolism would decrease the action of the drug

197
Q

If cytochrome P450 liver enzymes are inhibited, it

A

if there is less of the enzyme there is decreased metabolism (less breakdown) so the drug stays in the body faster = inhibited (decreasing the rate of metabolism would increase the action of the drug

198
Q

what is a prodrug

A

Some drugs are administered in an inactive prodrug form so that they can be metabolically altered in the liver to the activated form
drug that doesn’t become active until going through metabolic phase I used to not lose as much of the drug in the liver

199
Q

prodrug helps to

A

facilitate oral bioavailability
decrease GI toxicity
prolong elimination of ½ life of a drug

200
Q

Differences bw Phase I Metabolism & First-Pass Metabolism

A

first phase of metabolism in the liver
after drug has exerted its effect and gone to receptor organs and now it is taken out of the body here and happens for all types of route of administer

what is first pass metabolism?
happens in the liver but happens with oral meds and it detoxifies it and happens before it goes into the bloodstream
before the drug goes to the receptor organs and only happens for the oral route

location is the same but function and ____ are different

201
Q

what is phase II

A

Conjugation/Hydrolysis

these reactions hydrolyze or conjugate a drug to a larger polar molecule by adding other molecular groups such as glutathione, sulfate, and acetate
This reaction inactivates the drug or enhances the drug solubility and excretion rate into urine or bile

202
Q

what is conjugation

A

forming a compound by joining two or more chemical compounds

203
Q

what is hydrolysis

A

reaction involving breaking of a bond in a molecule using water

204
Q

effect of Phase I & II on a drug are dependent on presence of

A

other drugs taken at the same time

205
Q

some drug classes, like barbiturates, are powerful _____ of enzymes mediating Phase I reactions

A

inducers

206
Q

what do barbiturates do to metabolic process

A

barbiturates speed up metabolic process & decrease action of drugs being taken simultaneously - drug leaves the body faster

207
Q

what does erythromycin do to enzymes in metabolic process

A

can inhibit these enzymes
slow down the metabolic process and increase action of drugs being taken simultaneously - drug stays in the body longer

208
Q

what is polypharmacology

A

taking several drugs together

209
Q

drug to drug interactions are important for setting appropriate drug dosage and monitoring adverse effects

A

true

210
Q

Outcomes of Phase I & II reactions; the liver can

A

convert active drug to inactive - most common outcome; inactive drug formed from the parent drug

convert inactive drug form (prodrug) to active - inactive parent drug is converted to active drug after metabolism

convert active drug to active - active parent drug is converted to a second active drug

211
Q

what is the function of phase I and II biotransformation

A

to enhance the hydrophilic nature of a hydrophobic drug so it can excrete out of the body easily

212
Q

what is drug excretion

A

movement of a drug and or its metabolites out of the body

213
Q

how is a drug primariliy excreted?

A

primarily through renal excretion (urine) & biliary excretion (feces
minor through respiratory (breath – i.e., alcohol, useful for Breathalyzer), and dermal routes (sweat) & smaller through breast milk during lactation

214
Q

renal flow comprises ~_____% of total systemic blood flow

A

25

215
Q

what happens if a drug is still fat soluble when it reaches the kidney

A

it will be reabsorbed by the kidneys and placed back into the bloodstream

216
Q

what happens if kidney function is affected

A

excretion of the drug will take longer and can increase drug toxicity

217
Q

waht kidney conditions affect its function

A

Age (kidney function declines with age)
Drug toxicity
Altered kidney function from disease such as
diabetes (impaired renal blood supply)
hypertension
renal diseases - polycystic kidneys & glomerulonephritis from any case
cancers

218
Q

After being metabolized, the drug is excreted out of the body
Primarily through

A

the kidneys (urine), liver (bile), and gut (feces)

219
Q

waht is drug clearance?

A

rate of elimination of drug from body relative to the concentration of the drug in the plasma
rate at which drug would need to be cleared from the plasma to account for the change sought by the drug in the body

220
Q

what is drug clearance equation

A

Clearance = Metabolism + Excretion ÷ Drug(plasma)
Metabolism and excretion are expressed as rates (amount ÷ time)

221
Q

what are clearance mechanisms

A

metabolism and excretion

222
Q

Although metabolism and excretion (collectively called clearance mechanisms) are different physiologic processes, the endpoint is equivalent

A

Reduction in circulating levels of an active drug
Clearance(total) = Clearance(renal) + Clearance(hepatic) + Clearance(other)

223
Q

what are drug elimination kinetics

A

zero order and first order elimination kinetics

224
Q

Elimination of a constant quantity per time unit of the drug quantity present in the organism

A

zero order elimination kinetics

225
Q

Elimination of a constant fraction per time unit of the drug quantity present in the organism

A

first order elimination kinetics

226
Q

what drugs are eliminated through zero order

A

Salicylates, ethanol, and cisplatin

227
Q

what drugs are eliminated through first order

A

The elimination is proportional to the drug concentration
95% of drugs are eliminated in this fashion

228
Q

what is a drug half life

A

time required for the serum drug concentration to decrease by 50% (T½)

229
Q

quickly removed from the body; short duration of action

A

short half life

230
Q

slowly removed from the body; long duration of action

A

long half life

231
Q

drug is cleared (removed) from body in ~ ______ half-lives

A

four to five

232
Q

Renal failure ______ excretion rates and _______ the half-life of drugs

A

decreases
increases

233
Q

Knowledge of half-life allows the estimation for frequency of dosing of the drug required to maintain the therapeutic range of the drug in plasma

A

true

234
Q

most drugs are eliminated by zero-order kinetics

A

false
first order

235
Q

all factors affecting the volume of distribution and clearance of a drug also affect

A

half life of a drug

236
Q

formula used to calculate the elimination half-life of a drug based on the volume of distribution and clearance of the drug

A

t1/2 = 0.693 x Vd ÷ Clearance

237
Q

which one bypasses all barriers? what is the risk?

A

intrathecal - directly into the CSF and bypassess because of this.

risk: blow past the barriers, acts immediately, if anything goes wrong (allergy etc.) there isn’t much time to react

238
Q

what is wrong with zero order kinetics?

A

ex: 100 mg in body, but for this drug, body removes 20 mg but if there is 200 mg it sti8ll only removes 20 mg
what is the issue with this? becomes toxic

239
Q

what is zero order kinetics

A

amount of drug present, body will eliminate a constant amount no matter how much is in the body

240
Q

what is first order kinetics

A

if the level in body goes up (higher medication), the amount leaving the body also goes up
adaptive

241
Q

constant

A

zero order

242
Q

proportional

A

first order

243
Q

how much time the drug will be in the body

A

half life

244
Q

half life is constant for most drugs

A

true

245
Q

how do we measure a drug concentration

A

measure drug amount in the body by concentraton of the drug in the plasma because it is the easiest way to do it

246
Q

long half life

A

slowly removed from the body

247
Q

short half life

A

doesn’t stay in the body long

248
Q

what is steady state

A

amount you want in the bloodstream to brig about the best change you want from the drug

249
Q

it takes about four to five half-lives for a drug to build up to a steady state (level amount) in the body

A

true

250
Q

if drug is in body longer, half life increases, which increases concentration

A

true

251
Q

what is t1/2

A

elimination half life

252
Q

what is Vd

A

volume of distribution

253
Q

what is .693

A

approximation of inverse of 2

254
Q

what is the formula to calculate elimination half life of a drug

A

t1/2 = 0.693 x Vd ÷ Clearance

255
Q

what is redistribution of drugs

A

movement of drugs from specific site of action to nonspecific sites of action

256
Q

redistribution to a nonspecific sites will terminate the drug’s action

A

true

257
Q

what are examples of redistribution

A

An “induction” agent is administered to induce sleep before anesthesia for surgery
After a few minutes, the action is terminated
Because the drug has been redistributed from the CNS via the plasma to skeletal muscle (action terminated) to fat depots in the body (no action)

258
Q

A highly absorbed drug generally requires

A

lower dose than a poorly absorbed drug

259
Q

A highly distributed drug requires

A

higher drug doses

260
Q

The elimination rate of a drug influences

A

its half-life and, therefore, determines the frequency of drug doses to maintain therapeutic levels

261
Q

liver and kidney function (involved in cleaerance) affect

A

½ life and drug dosage

262
Q

The therapeutic dosing of a drug seeks to maintain

A

trough (lowest) plasma concentration above minimally effective levels
peak (highest) plasma concentration below toxic levels

range of dosage
the most you can give to get the effect or the least amount you can give to bring about the therapeutic change wanted

263
Q

what is steady state accumulation

A

At a regular dosing frequency, the drug does not accumulate, and a steady state (equilibrium) is reached
Steady-state occurs because the elimination process is concentration dependent

264
Q

The higher the drug concentration, the _____ is the amount eliminated per unit time

A

greater

265
Q

After several doses, the plasma drug concentration will have climbed to a level at which

A

the amounts eliminated and taken in per unit of time become equal – steady state is reached

266
Q

It takes about four to five half-lives of a drug to build up to a steady state level in the body

A

true

267
Q

what is a loading dose

A

Higher initial or loading dose of drugs administered to compensate for drug distribution in the tissues from plasma

268
Q

what is a maintenance dose

A

Once steady state is reached, subsequent drug doses must replace only what is lost through metabolism and excretion

269
Q

Most drug elimination follows first-order kinetics meaning

A

Elimination increases as drug concentration in plasma increases

270
Q

what happens when the body metabolism is saturated at therapeutic or slightly above therapeutic values

A

elimination may change from first-order to zero-order kinetics
elimination rate then doesn’t increase with increasing concentration
Continuous drug administration in such cases, can result in rapid drug accumulation with drug concentrations reaching toxic values

Pharm & Ototoxicity (10 decks)

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