Lecture 3 Flashcards

1
Q

ADME

A

Absorption
Distribution
Metabolism
Excretion

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2
Q

Study of how a body influences a drug

A

Pharmacokinetics

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3
Q

________ is a breakdown of the processes which affect a drug molecule

A

ADME

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4
Q

The movement of a drug from the site of administration into the bloodstream
Drugs enter the bloodstream for the purpose of traveling to their target tissues

A

Absorption

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5
Q

Administration route
Cell membrane permeability
Drug formulation
Physiology: gastric emptying, surface area, temperature

A

Factors that affect Absorption

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6
Q

non-invasive, good for repeated dosing, safety
Subject to first-pass metabolism
Prodrugs

A

Absorption: ORAL ROUTE

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7
Q

Intravenous: rapid
Subcutaneous: slower
Intramuscular: larger volumes, slow-release formulas

A

Routes: Parenteral Routes

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8
Q

Localized
Mucous membranes? Rapid uptake

A

Routes: Topical

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9
Q

Sustained release
Can be irritating

A

Routes: Transdermal

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10
Q

Rapid, efficient
Initial localization to pulmonary system

A

Routes: Inhaled

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11
Q

When it goes into the stomach first and then the liver it’s called

A

First pass

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12
Q

How much of the drug gets absorbed
Usually described as a percentage
Oral? IV?

A

Bioavailability

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13
Q

Two drugs that have the same bioavailability and same concentration of active ingredient

A

Bioequivalents (generic vs brand)

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14
Q

Drug molecules can cross a barrier passively or actively
Active transport
Passive diffusion

A

Movement across membranes

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15
Q
  1. molecule size
  2. lipophinicity
  3. drug ionization
A

Membrane permeability

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16
Q

Smaller drugs are absorbed faster than larger drugs

A

Molecule size

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17
Q

Lipophilic = increased absorption

A

Lipophilicity

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18
Q

Want drugs to be neutral when they are absorbed, not ionized
A basic drug in an acidic environment will not absorb well
An acidic drug in a basic environment will not absorb well

A

Drug ionization

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19
Q

Drugs are designed and formulated with the pH of the enteral environment in mind
Weakly acidic drugs are meant to be absorbed in the stomach
Likewise, weakly basic drugs are meant to be absorbed in the intestine (alkaline environment)
Think: neutral is better than ionized, and the pH of the environment surrounding the drug molecule impacts it’s charge
How do we know whether a drug is intended for stomach or intestinal absorption?

A

Ionization

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20
Q

Coatings
Buffered medications
Hydrogels
Sustained v. controlled release

A

Absorption: drug formulation

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21
Q

Enteric coating (“EC”)
Prevents drug from dissolving in stomach
Enteric coated tabs absorb in the intestine
Therefore, we do not EVER crush or dissolve an enteric coated tab prior to administration! (no GT tubes, no pudding)

A

Coatings

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22
Q

Drug contains ions to decrease gastric acidity

A

Buffered Medication

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23
Q

drug released over period of time

A

Controlled release

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24
Q

drug released at a constant rate over time

A

Sustained release (“SR”)

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25
Q

high dose intended to release over extended period.
Crushing, chewing, splitting or opening immediately releases the entire dose

A

Extended-release (“XR”) formulations

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26
Q

_________ drugs cannot be administered PO
Example: InsulinProtein would be digested by the stomach and rendered useless. That is why we inject insulin.

A

Protein-based

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27
Q

some drugs may have unpleasant effect on oral cavity (bitter taste, stain teeth, irritate mucosa). Any drug with an oral cavity effect may have a more palatable alternative (e.g: sweetened liquid) so ask pharmacy!

A

Other considerations for crushing

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28
Q

Gastric emptying
Blood flow
Surface area
Body temperature

A

Psysiologic and other factors that affect absorpotion

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29
Q

Fatty foods delay emptying
Some drugs can decrease motility
Nursing implication for this?

A

Gastric emptying

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30
Q

Increased blood flow = increased absorption

A

Blood flow

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31
Q

Can affect topicals

A

Body Temperature

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32
Q

Transport of a drug by the bloodstream to its site of action

A

Distribution

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33
Q

Blood flow to target tissue
Drug solubility (lipophilic/hydophobic)
Drug-Protein binding
Special physiologic barriers
Blood-Brain Barrier
Fetal circulation

A

Factors affecting distribution

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34
Q

More blood flow = more drug reaching target tissue
Drugs distribute first to areas with ++ blood supply

A

Blood Flow to target tissue

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35
Q

Lipid-soluble cross cell membranes more readily
Drugs in their active form are usually lipophilic
Question for thinking! – equal amounts of lipid-soluble drug and water-soluble drug – which one will have higher plasma concentration?

A

Solubility

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36
Q

Drugs will bind to proteins in the bloodstream (albumin)
Only unbound drug molecules can freely distribute – “active”
low albumin levels = risk for toxicity

A

Drug-protein binding

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37
Q

two medications that are highly protein-bound may “compete” for binding sites on the albumin.

A

Protein binding site competition

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38
Q

Creates more free, unbound drug = unpredictable drug response
This is called a ______ interaction

A

drug-drug

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39
Q

when the presence of one drug decreases or increases the action of another drug administered concurrently

A

Drug to Drug Interaction

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40
Q

Does not contain capillary pores
Protects brain from pathogens and toxins
Only lipid-soluble drugs able to cross
Not fully developed in neonates
Inflammation can increase permeability

A

Blood-brain barrier

41
Q

Prevents harmful substances from passing from mother’s blood stream to fetus
Permeability of barrier changes during pregnancy
However, some drugs can cross (alcohol, cocaine, caffeine, some prescription meds)
Pregnancy categories for drugs
Must consider if patient is of childbearing age prior to prescribing a drug.

A

Fetal-placental barrier

42
Q

Also called Biotransformation

A

Metabolism

43
Q

________ alteration of a drug into:
Inactive metabolite
A more soluble compound
A more potent metabolite (conversion from a Prodrug)
A less active metabolite

A

Biochemical

44
Q

Large class of enzymes, known as microsomal enzymes
Targeted against lipophilic medications (most meds)

A

Hepatic Enzymes: Cytochrome P450 System

45
Q

Drugs that are metabolic targets of specific enzymes are said to be _______ of those enzymes

A

substrates

46
Q

So, lipid-soluble meds are “substrates” of the _____ enzymes

A

CYP450

47
Q

Lots of drugs ______ the CYP450 system – results in toxicity
Some substances _______ the CYP450 system – “inducers”

A

inhibit; activate

48
Q

CYP450 _____ drugs

A

metabolizes

49
Q

genetics, presence of other drugs, certain foods

A

Influence inhibition and induction

50
Q

Inducer
Other inducers: caffeine, chronic alcohol, chronic tobacco

A

St. John’s Wort (NHP)

51
Q

Inhibitor

A

Grapefruit Juice

52
Q

CYP450 System responsible for _______ effect!

A

first-pass

53
Q

__________ affects CYP

A

Nutritional status

54
Q

Metabolic pathway competition: 2 drugs competing for the same enzyme? -> another ______________

A

drug-drug interaction

55
Q

Structural change = _______ change

A

functional

56
Q

Metabolite could be __________ (because metabolism inactivated the drug)

A

non-functional

57
Q

Metabolite could be __________ (because the metabolism activated the prodrug)

A

functional

58
Q

Codeine is a prodrug for

A

morphine

59
Q

Some metabolites are _______ to the liver

A

toxic

60
Q

Tylenol metabolites – _______, __________
*when used appropriately – Tylenol has high safety profile!

A

liver, kidneys

61
Q

Infants: immature CYP system
Elderly: enzyme activity reduced
Genetic polymorphisms

A

Lifespan: metabolism

62
Q

Elimination of drugs from the body
- Kidney
- Pulmonary
- Glandular
- Intestinal/fecal

A

Excretion

63
Q

_________ affects blood concentration
Inverse -> more excretion = lower blood concentration

A

Excretion rate

64
Q

May come to kidney as metabolites, or in active form
Metabolized drugs are easier to excrete (due to polarization + water solubility)
Passive diffusion in the glomerulus
Many drugs stay in the urine and do not get resorbed
Changes in urine pH can influence whether a molecule gets reabsorbed
Kidney damage = reduced renal excretion -> clinical implication?

A

Renal excretion

65
Q

Gases and volatile liquids
Most drugs excreted unmetabolized
Excretion rate affected by resp rate and blood flow

A

Pulmonary Excretion

66
Q

Sweat, saliva, breast milk, seminal fluid
Water-soluble molecules

A

Glandular Excretion

67
Q

“biliary excretion”
Enterohepatic recirculation

A

Intestinal Excretion

68
Q

Pharmacotherapy goals
Onset of action
Duration of action
Peak effect
Peak level
Half-life
Steady state

A

Time-response relationships

69
Q

Maintain drug at concentration that produces therapeutic response

A

Pharmacotherapy goals

70
Q

time required for a drug to elicit therapeutic response

A

Onset of action

71
Q

time period during which drug is in therapeutic range

A

Duration of action

72
Q

time required to reach maximal therapeutic response
Corresponds physiologically to increasing drug concentration at site of action
Not to be confused with peak level

A

Peak effect

73
Q

_________ = highest blood level; Trough Level = lowest blood level

A

Peak Level

74
Q

Time required for serum levels to be reduced by one half (50%)
Represents the rate of elimination
5 half-lives to reduce by 97%
Clinically useful to determine steady-state, estimates duration of action
Shorter half life – given more frequently (morphine half life 3 hrs)
Steady State
Physiological state in which the amount of drug removed via elimination = the amount of drug absorbed with each dose

A

Half-life

75
Q

__________ = consistent levels that correlate with maximum therapeutic benefits
Steady state is achieved in about 5 half-lives worth of time for the drug

A

Steady state

76
Q

Topical (direct app. to skin)
Optic
Otic
Vaginal
Inhaled
Nebules
Rectal

A

Medication adminstration

77
Q

topical administration is often used to produce an effect at the place it is applied
Unintended adverse effects usually due to drug being absorbed into circulation

A

Local effects

78
Q

some drugs given topically are absorbed into blood to produce effects throughout the body
Slow release preparations
Consider the pharmacokinetic principle of “Absorption”

A

Systemic effects

79
Q

Can be formulated and applied to achieve local or systemic effects
Application is directly to the site of intended action
Fewer adverse effects than enteral or parenteral routes
No first pass metabolism or digestion by liver enzymes
For some routes, patient does not have to be conscious

A

Advantages of Topical

80
Q

Can be irritating to site of administration
Local application can produce systemic adverse effects

A

Disadvantages of Topical

81
Q

Sublingual*
Buccal*
Lotion, ointment, cream, powder, foam, patch, disc
Direct application to skin or mucosa
Direct application to mucous membrane
Inhalation of medicated aerosol spray
Inhalation of dry powder medication
Inserting medication into a body cavity

A

“Topical” covers many forms of drug

82
Q

Cleansed + Dried, hairless
Assess prior to application (elderly – thin skin)
No open areas (unless specified for wound – sterile technique!)

A

Skin Prep

82
Q

Skip prep
Use gloves/applicators
Thicknss of application

A

Skin Applications

83
Q

Lotions + ointments

A

spread evenly

84
Q

rub in firmly

A

Liniment

85
Q

If applying _______, have pt turn their head to avoid accidental inhalation

A

powder

86
Q

a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream.

A

Transdermal patch

87
Q

Nasal spray, drop, or tampon

A

Intransal route

88
Q

easy, avoid first-pass

A

Intranasal advantages

89
Q

Cilia damage, mucosal irritation, absorption may be affected by mucous secretions

A

Intranasal disadvantages

90
Q

Spray: tilt head back, to the side being treated
Drops: depends on target area
Remain in position 5 minutes

A

Intranasl positioning

91
Q

Sympathomimetic medications
Long-term decongestant use

A

Intranasal

92
Q

tilt the head backward

A

Instilling Nasal Drops: Posterior Pharynx

93
Q

place head gently over edge of bed OR pillow under shoulders and tilt head back

A

Nasal drops: Ethmoid or Sphenoid sinus

94
Q

tilt head back and turn towards the side to be treated

A

Nasal drops: Frontal or Maxillary

95
Q

Forms: drops, ointments, Intraocular disc

A

Opathalmic

96
Q

Gently roll container
Instruct patient to look up
Non-dominant hand: use cotton ball, gently pull lower lid open to expose conjunctival sac
Dominant hand: rest on patient forehead, hold dropper 1-2 cm above conjunctival sac
Do not touch dropper to the eye
Do not touch dropper with your fingers
Never apply gtts to the cornea; drops should go into the conjunctival sac
If you miss (patient moved or blinks), repeat procedure
Drops before ointment

A

Instilling drops

97
Q
A