Week 1

Question 1

Pharmacokinetics

Answer 1

study of drug movement throughout the body

ADME

Question 2

Absorption

Answer 2

Movement of drug from site of administration into the systemic circulation

Question 3

Factors Affecting Drug Absorption

Answer 3

Rate of dissolution
Surface area
Blood flow
Lipid solubility
pH partitioning

Question 4

Distribution

Answer 4

Movement of drugs from blood to site of action

Question 5

Drug distribution is determined by what factors

Answer 5

Blood flow to tissues
Exiting the vascular system
Entering cells

Question 6

Exiting the vascular system

Answer 6

Typical capillary beds

- pass through them

Question 7

Blood-brain barrier

Answer 7

Capillaries of the central nervous system have tight junctions that prevent free diffusion

Question 8

Blood brain barrier

Answer 8

Only drugs that are lipid soluble or that have a transport system can cross the blood-brain barrier to a significant degree

Question 9

Placental Drug Transfer

Answer 9

Membranes of the placenta do NOT constitute an absolute barrier to the passage of drugs

Question 10

Protein Binding

Answer 10

Drugs can form reversible bonds with various proteins

Plasma albumin is the most abundant and important protein

Question 11

Entering Cells

Answer 11

Some drugs must enter cells to reach the site of action
Most drugs must enter cells to undergo metabolism and excretion
Many drugs produce their effects by binding with receptors on the external surface of the cell membrane

Question 12

Bioavailability

Answer 12

Amount of active drug that reaches the systemic circulation from its site of administration

Question 13

drug metabolism

Answer 13

aka biotransformation

Question 14

drub metabolism

Answer 14

Defined as the enzymatic alteration of drug structure

most often takes place in liver

Question 15

1st pass effect

Answer 15

Drugs are absorbed 
enter hepatic circulation
liver metabolizes drug to inactive form 
inactive drug leaves liver and enters general circulation

Question 16

P450 system

Answer 16

Hepatic metabolism takes place by hepatic microsomal enzyme system

I Drugs can be P450 substrates, inducers, or inhibitors

Question 17

Therapeutic Consequences of Drug Metabolism

Answer 17

Accelerated renal drug excretion
Drug inactivation
Increased therapeutic action
Activation of prodrugs
Increased or decreased toxicity

Question 18

Excretion

Answer 18

Defined as the removal of drugs from the body

kidneys are the primary site

Question 19

steps in renal drug excretion

Answer 19

Glomerular filtration
Passive tubular reabsorption
Active tubular secretion

Question 20

Factors that modify renal drug excretion

Answer 20

pH-dependent ionization
Competition for active tubular transport
Age

Question 21

half life

Answer 21

Defined as the time required for the amount of drug in the body to decrease by 50%
Percentage versus amount
Determines the dosing interval

Question 22

drugs with short half lives

Answer 22

give more frequently

Question 23

drugs with longer half lives

Answer 23

given less often

qd

Question 24

Drug Levels Produced with Repeated Doses

Answer 24

Process by which plateau drug levels are achieved
Techniques for reducing fluctuations in drug levels
Loading doses versus maintenance doses

Question 25

receptor

Answer 25

any functional macromolecule in a cell to which a drug binds to produce its effects (generally proteins)

Question 26

receptor binding

Answer 26

usually reversible

Question 27

when a drug binds to receptor

Answer 27

it will mimic or block the action of endogenous regulatory molecules and increase or decrease the rate of physiologic activity normally controlled by that receptor

Question 28

Important Properties of Receptors

Answer 28

Receptors are normal points of control of physiologic processes
Under physiologic conditions, receptor function is regulated by molecules supplied by the body
Drugs can only mimic or block the body’s own regulatory molecules
Drugs cannot give cells new functions
Drugs produce their therapeutic effects by helping the body use its preexisting capabilities

Question 29

the more selective a drug is

Answer 29

the fewer side effects it will make

Question 30

each type of receptor participates

Answer 30

in regulation of just a few processes

Question 31

simple occupancy theory

Answer 31

cannot explain different maximal efficacies of drugs

Question 32

affinity

Answer 32

strength of attraction

Question 33

intrinsic activity

Answer 33

ability of drug to activate a receptor upon binding

Question 34

agonist

Answer 34

molecules that activate receptors
endogenous regulators
have both affinity and high intrinsic activity
ex-dobutamine mimics NE at cardiac receptors

Question 35

antagonist

Answer 35

Produce their effects by preventing receptor activation by endogenous regulatory molecules and drugs

Affinity but no intrinsic activity

No effects of their own on receptor function

If there is no agonist present, an antagonist will have no observable effect

Question 36

partial agonist

Answer 36

These are agonists that have only moderate intrinsic activity
The maximal effect that a partial agonist can produce is less than that of a full agonist
These can act as antagonists as well as agonists

Question 37

Drug Responses That Do Not Involve Receptors

Answer 37

Simple physical or chemical interactions with other small molecules
Examples of receptorless drugs:
Antacids, antiseptics, saline laxatives, and chelating agents

Question 38

therapeutic index

Answer 38

Measure of a drug’s safety

Ratio of the drug’s LD50 (average lethal dose to 50% of the animals treated) to its ED50

Question 39

larger/higher TI

Answer 39

safer drug

Question 40

smaller/lower TI

Answer 40

less safe drug