Pt 713 Pharmacokinetics

Front 1

What is the movement of a drug through the body called (what the body does to the drug)?

Back 1

Pharmacokinetics

Front 2

What are 3 enteral ways to administer drugs?

Back 2

1) Oral
2) Sublingual
3) Rectal

Front 3

What are the benefits of oral administration of a drug?

Back 3

Safe and easy

Front 4

What are 5 disadvantages to taking an oral drug?

Back 4

1) Some drugs can be difficult to absorb and are not lipid soluble
2) Some drugs break down too quickly
3) Can cause stomach or esophagus irritation
4) Timing is unpredictable based on metabolism and gut motility
5) First-pass effect--absorbed in gut, metabolized in liver before getting to the target (small dose at target)

Front 5

What is the first-pass effect?

Back 5

When a drug is absorbed in gut, metabolized in liver before getting to the target (smaller dose at target)

Front 6

What type of enteral administration is placed under the tongue?

Back 6

Sublingual

Front 7

How is the sublingual administration absorbed?

Back 7

Through the oral mucosa into the venous system

Front 8

What type of enteral administration has no first-pass effect?

Back 8

Sublingual

Front 9

What type of enteral administration has a limited amount that can be given?

Back 9

Sublingual

Front 10

What is a disadvantage of a sublingual administration of a drug?

Back 10

Some drugs cannot pass through the oral mucosa

Front 11

What is an example drug given sublingually?

Back 11

Nitroglycerin pill for people feeling onset of MI

Front 12

What are 4 parenteral ways of administering drugs?

Back 12

1) Inhalation
2) Injection
3) Topical
2) Transdermal

Front 13

What are 2 disadvantages to injecting drugs (parenteral approach)?

Back 13

1) Possibility of infection or irritation
2) Some are difficult or nearly impossible to self-administer

Front 14

What are 4 different ways to inject drugs?

Back 14

1) Intravenous (systemic)
2) Intra-arterial (fairly local)
3) Subcutaneous (local)
4) Intramuscular (local)

Front 15

What 3 types of injections are directed locally?

Back 15

1) Intra-arterial (fairly local)
2) Subcutaneous
3) Intramuscular

Front 16

What type of injection is directed systemically?

Back 16

Intervenous

Front 17

What type of injection is a known quantity delivered directly to peripheral bloodstream?

Back 17

Intravenous

Front 18

What could be an adverse reaction to injecting a drug?

Back 18

If bolus amount is given

Front 19

What does bolus mean?

Back 19

Large amount of drug delivered at one time (could cause adverse reaction)

Front 20

What does an IV cannula allow?

Back 20

Allows steady infusion of a drug as a oppose a bolus which delivers all at once

Front 21

What is an advantage to IV cannula?

Back 21

Can reach the target site rapidly

Front 22

What is an intramuscular injection used for?

Back 22

Used for local treatment and prolonged release into systemic circulation (like the flu shot)

Front 23

What is a disadvantage to an intramuscular injection?

Back 23

Can cause muscle pain and soreness

Front 24

How is the topical administration of drug used?

Back 24

Applied and absorbed into the skin or mucous membrane (often poorly absorbed)

Front 25

What is a topical drug often used for?

Back 25

Local conditions on skin (aloe gels, antibiotics, etc)

Front 26

What is used either for local or systemic conditions?

Back 26

Topical through the mucosa membrane (better absoption than skin)

Front 27

What is a disadvantage to absorbing a drug through mucosa membrane?

Back 27

Can cause adverse systemic effects if too much is absorbed in the blood stream

Front 28

What 2 things does drug absorption depend on?

Back 28

1) Blood flow to administration site
2) Concentration of the drug

Front 29

What does bioavailability refer to?

Back 29

Extent to which the drug reaches the systemic circulation

Front 30

What 2 things does bioavailabilty depend on?

Back 30

1) Route of administation (first-pass effect--oral always less bioavailable than direct admin)
2) Ability of drug to cross membranes

Front 31

What are 2 types of drug administration?

Back 31

1) Enteral
2) Paraenteral

Front 32

Define enteral administration of a drug

Back 32

When the drug travels through the alimentary canal or tube of the gut to the anal canal

Front 33

Define parenteral administration of a drug

Back 33

When the drug travels through alternates routes aside from the alimentary canal

Front 34

What are 2 benefits for using paraenteral administration of a drug?

Back 34

1) Not a first-pass effect
2) Delivered directly to the target

Front 35

What 2 benefits for taking a drug rectally?

Back 35

1) Vomiting
2) Unconscious

Front 36

What are 2 disadvantages for taking a drug rectally?

Back 36

1) Some drugs are not absorbed well
2) Rectal mucosa can be irritated

Front 37

What is inhalation administration useful for?

Back 37

When treating the lungs (bronchodialators)

Front 38

What are 2 disadvantages for using inhalation administration?

Back 38

1) Some drugs can irritate the respiratory tract
2) Difficult to predict how much drug will reach the target tissue

Front 39

Why is intra-arterial injections difficult and dangerous?

Back 39

Because there is high pressure in the arteries versus the veins

Front 40

What are 2 benefits to injecting intra-arterially?

Back 40

1) Direct delivery into the bloodstream
2) Directed at the tissue site (some cancer drugs are administered this way)

Front 41

What are subcutaneous injections used for?

Back 41

1) local effects
2) slower release time

Front 42

What is an advantage to using subcutaneous injections?

Back 42

Can self-administer

Front 43

What is a disadvantage to using subcutaneous injections?

Back 43

Area can become irritate if using same site

Front 44

What are 2 examples of subcutaneous injections?

Back 44

1) insulin
2) TB

Front 45

What is meant by transdermal administrating of a drug?

Back 45

Apply drug to the skin to subcutaneous or circulation

Front 46

What 2 basic properties must a transdermal administration possess?

Back 46

1) Drug must penetrate the skin
2) Drug must not degrade in the dermis

Front 47

What are 3 innovative administration methods?

Back 47

1) Controlled release preparations used to take less often
2) Implanted drug delivery systems
3) Targeting drugs to specific tissues

Front 48

What are 4 ways for a drug to penetrate the membrane?

Back 48

1) Passive diffusion
2) Active transport
3) Facilitated diffusion
4) Endocytosis

Front 49

What does passive diffusion require?

Back 49

1) Concentration gradient
2) Neutral ions, non-ionized form will diffuse easily
3) No energy

Front 50

What are 4 types of passive diffusion?

Back 50

1) Ionization's effects
2) Diffusion trapping
3) Diffusion between tight junctions
4) Osmosis

Front 51

What is the effect of ionization on lipid diffusion (ionization's effects)?

Back 51

Most drugs are weak acids or bases having potential to become charged based on pH which will affect absorption (decrease it since it is now non-lipid soluble)

Front 52

What are 2 transdermal methods?

Back 52

1) Iontophoresis
2) Patches

Front 53

What is diffusion trapping?

Back 53

Drug is excreted in a different location from urine due to the acidity (drug that is trapped in the nephron)

Front 54

What is diffusion between tight junctions?

Back 54

An area where passive diffusion can occur by going in one cell and out of another cell

Front 55

What is osmosis?

Back 55

Diffusion of water

Front 56

What is active transport permeability? (3)

Back 56

1) Requires energy
2) Protein carrier
3) Goes against concentration gradient

Front 57

What is facilitated diffusion? (3)

Back 57

1) No energy required
2) Protein is needed
3) Goes with concentration gradient

Front 58

What is endocytosis?

Back 58

The eating of a drug by way of a vessicle

Front 59

What is distribution?

Back 59

The movement of a drug to the target site

Front 60

What are 4 requirements of distribution of a drug?

Back 60

1) Membrane/tissue permeability
2) Blood flow
3) Binding to plasma proteins
4) Binding to subcellular compartments

Front 61

What is volume of distribution (Vd)?

Back 61

The amount of a drug administered/concentration of drug in plasma

Vd=amount/plasma conc

Front 62

Where are drugs stored? (4)

Back 62

1) Fat
2) Bones
3) Muscle tissues
4) Organs

Front 63

What are possible adverse consequences of drug storage? (2)

Back 63

Become toxic and reservoir effects

1) Prevented drug reaching target site
2) Drug leaks out causing effects at target site later

Front 64

What is biotransformation?

Back 64

Drug metabolism

Front 65

Where does biotransformation occur?

Back 65

In the liver

Front 66

Biotransformation is what kind of an effect?

Back 66

First-pass effect

Front 67

What are 4 types of biotransformation reactions?

Back 67

1) Oxidation
2) Reduction
3) Hydrolysis
4) Conjugation

Front 68

What are biotransformation reactions driven by?

Back 68

An enzyme

Front 69

What is oxidation?

Back 69

Add O2 and remove H

Front 70

What is the key method of biotransformation?

Back 70

Oxidation

Front 71

What is reduction?

Back 71

Remove O2 and add H

Front 72

What is hydrolysis?

Back 72

The break down of a drug into 2 parts

Front 73

What is conjugation?

Back 73

An intact drug couples with something else in the body (i.e. amino acid) or uses a product of either oxidation, reduction or hydrolysis

Front 74

What are 4 elimination methods?

Back 74

1) Biotransformation
2) Biotransformation reactions
3) Enzyme induction
4) Excretion

Front 75

What is enzyme induction?

Back 75

When prolonged drug use enables enzymes to break down the drug more easily which can influence tolerance

Front 76

How does enzyme induction occur? (2)

Back 76

1) Make more enzymes and store them in the body
2) Enzymes stay longer and break down less

Front 77

What is excretion?

Back 77

The removal a drug from the body

Front 78

Where does excretion primarily occur?

Back 78

In the kidneys

Front 79

What helps excretion occur?

Back 79

Biotransformation by making the drug more water soluble and highly charged

Front 80

What are 2 ways to compare elimination rates?

Back 80

1) Clearance rate
2) Half-life rate

Front 81

What is clearance (CL)?

Back 81

The process by which active form of the drug is removed from the bloodstream

Front 82

CL=

Back 82

rate of drug elimination/plasma drug conc (process by which active form of the drug is removed from the blood stream)

Front 83

CL(organ)=

Back 83

Q*(Ci-Co)/Ci)

Blood flow * (conc in - conc out)/conc in

Front 84

What is the extraction ratio?

Back 84

The fraction of the drug removed from the blood stream as it passes through an organ (Ci-Co)/Ci

Front 85

What is half-life?

Back 85

Amount of time necessary for 50% of the drug remaining to be eliminated

Front 86

What 2 things does half-life depend on?

Back 86

1) Clearance (CL)
2) Volume of distribution (Vd)

Front 87

Why do PTs care about dosing schedules?

Back 87

Because we will see different functions based on when a drug was administered

Front 88

9 factors that affect elimination

Back 88

1) Liver/kidney damage
2) Genetics
3) Disease
4) Drug interactions
5) Age
6) Diet
7) Sex
8) Environmental (toxins)
9) SCI changes in gut motility