Fundamentals Of Drug Action

Front 1

________ describes how a drug gets to the site of action

Back 1

Pharmacokinetics

Front 2

the amount of drug in the body at any given time is determined by five processes:
(LADME)

Back 2

- L - liberation (release from pill)
- A - Absorptioin
- D - Distribution
- M - metabolism (biotransformation)
- E - Elimination or Excretion

Front 3

most drugs are absorbed through

Back 3

passive diffusion

Front 4

cell membranes act as a lipid barrier and allow ________ drugs to penetrate cell membranes more easily by diffusion. Drugs that are ________ do not diffuse easily in the lipid lyaer and either pass through aqueous pores or are prevented from entering the cell and thus are contained outside

Back 4

- lipid-soluble (lipophilic)
- water-soluble (hydrophilic)

Front 5

Factors that affect absorption include:

Back 5

- blood flow
- lipid soluble
- salt form of drug
- food and other drugs

Front 6

only _________ lipid soluble drugs will be absorbed acros cell membrane of tissues

Back 6

- nonionized (uncharged)

Front 7

How much of the drug changes to the ionized form will depend on the ______ of the drug and the _____ of the solution.

Back 7

- pKa
- pH

Front 8

the _____ refers to the concentration of the H+ ions and the ____ of a drug is related to the equilibrium that the drug has with its ionized form and is the pH at which the drug is ____% ionized and is a constant value

Back 8

- ph
- pKa
- 50%

Front 9

Generally the pKa of a weak acid is ____ and weak bases is _____

Back 9

- 3-5
- 8-10

Front 10

If a local tissue pH is more alkaline and closer to pKa values of drugs, onset of action is

Back 10

faster

Front 11

Inflammation = ______ tissue environment

Back 11

acidic

Front 12

Drugs with extensive first pass metabolism and low bioavailability include

Back 12

- morphine
- lidocaine
- Nitroglycerin

Front 13

________ is the disappearance of active drug from bloodstream or body

Back 13

Elimination

Front 14

_________ is the elimination through kidneys and out of body in urine

Back 14

Excretion

Front 15

The most common excretion route

Back 15

kidney

Front 16

Two major routes of Elimination:

Back 16

- Excretion
- Biotransformation

Front 17

the ______ is the primary site for biotransformation

Back 17

liver

Front 18

________ are drugs when orally administered they are inactive, but become active after biotransformation in the liver

Back 18

prodrugs

Front 19

Example of prodrugs include:

Back 19

- Levodopa (for parkinson's disease)
- Benazepril (Lotensin; antihypertensive drug)
- Losartan (Cozar)

Front 20

Biotransformation consist of ____ phases:

Back 20

- 2
- Phase I - involves enzymes in biotransformation (changes) of drugs
- Phase II - Drug or metabolite from phase I is conjugated or linked with highly water soluble compounds such as glucuronic acid to make it more water soluble so that it can be excreted

Front 21

_______ is the most common enzyme that metabolizes many drugs used in dentistry

Back 21

CYP3A4

Front 22

_______ enzyme metabolizes codeine, fluoxetine (prozac), and propanolol (heart medication)

Back 22

CYP2D6

Front 23

_______ enzyme metabolizes ibuprofen (advil)

Back 23

CYP2C9

Front 24

a _________ is the drug being metabolized

Back 24

substrate

Front 25

Clarithromycin (biaxin) is metabolized by

Back 25

CYP3A4

Front 26

some drugs are excreted in the bile by a process called

Back 26

biliary excretion

Front 27

__________ is the recycling of drugs and other substances by circulation of bile through intestine and liver

Back 27

enterohepatic recirculation

Front 28

______ is the time it takes for the concentration of the drug in the blood to fall to half (50%) of its original value

Back 28

Half-life (t 1/2)

Front 29

It takes about ____ half lives for a drug to be "considered" eliminated from the body

Back 29

4-5

Front 30

________ is the rate at which and the extent to which a drug is absorbed into the sytemic circulation

Back 30

bioavailability

Front 31

Most drug elimination follows ____ order of Kinetics

Back 31

first

Front 32

_______ means that the rate of drug elimination is equivalent to the drug concentration in the blood

Back 32

First order Kinetics

Front 33

__________ means that if drug elimination mechanisms become saturated a drug may exhibit zero order elimination because elimination of drug is at a constant rate and not dependent upon its concentration

Back 33

- zero order kinetics

Front 34

_______ is a large high dose of a drug given initially to rapidly establish a therapeutic plasma drug concentration

Back 34

Loading dose

Front 35

_________ is a lower dose used to maintain a desired drug level

Back 35

maintain dose

Front 36

________ is the concentration of the drug in the plasma between the MEC and the toxic concentration

Back 36

Therapeutic range

Front 37

_______ is the capacity of the body to remove a drug

Back 37

Drug clearance

Front 38

________ are the actions a drug has on the body and the mechanisms of action of the drug

Back 38

Pharmacodynamics

Front 39

Quantity of drug administerd is the

Back 39

drug dose

Front 40

_________ describes the response (what the drug does) and explains how the drug causes that response

Back 40

Drug response

Front 41

______ refers to the response of living matter to administered chemicals

Back 41

Drug action

Front 42

The site where such drug attachment takes place is termed the _______ and is regarded as being specific cell molecules

Back 42

receptor

Front 43

_______ will bind either a drug that is administered into the body or an endogenous substance

Back 43

receptor

Front 44

Receptors for hormones and neurotransmitters include

Back 44

- Adrenergic receptors
- muscarinic receptors
- nicotinic receptors
- insulin receptors
- histamine receptors

Front 45

Membrane transport proteins include

Back 45

- ion channels
- transporters for neurotransmitters

Front 46

Enzyme receptors include

Back 46

- cyclooxygenase
- carbonic anhydrase
- DNA polymers
- human immunodeficiency virus (HIV) protease
- Tyrosine kinase (for insulin)

Front 47

a _______ is a drug that rapidly combines with a receptor to initiate a response an rapidly dissociates or releases from the receptor

Back 47

agonist

Front 48

most drugs used today are

Back 48

agonist

Front 49

a _____ is a drug that binds to the receptor but does no dissociate and has not positive response and no efficacy. It blocks the reaction of an agonist

Back 49

antagonist

Front 50

a _______ is a drug that slowly binds to the receptor and produces a mild therapeutic response when administered alone, but may inhibit the action of an agonist when given concurrently, acting like and antagonist

Back 50

partial agonist

Front 51

______ is the dose or amount of a drug required to produce a particular or specific biologic effect relative to a given or implied standard of reference

Back 51

Potency

Front 52

_____ is the ability of a drug to produce a therapeutic effect regardless of the dose.

Back 52

Efficacy

Front 53

_______ is observing and measuring the patient's response obtained at different doses of the drug

Back 53

Graded dose

Front 54

_______ is the drug dose that produces 50% of the maximum possible response

Back 54

Effective Dose (ED50)

Front 55

______ is the ratio of a drug's toxic dose to its therapeutic dose

Back 55

Therapeutic index (TI)

Front 56

_______ is the drug dose at which 50% of the animals die

Back 56

Lethal dose (LD50)

Front 57

TI = _________

Back 57

LD50
____

ED50

Front 58

True or False
A "safe" drug will have a high TI of generally at least 10

Back 58

True