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Flashcards in pharmacodynamics Deck (85)
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1

Actions/effects of the drug on the body
Determines the group in which the drug is
classified and plays a major role in deciding
whether a group is appropriate therapy for
particular symptom or disease

pharmacodynamics

2


Specific molecules in a biologic system with
which drugs interact to produce changes in
the function of the system

RECEPTORS

3


Determine the quantitative relations between
dose or concentration of drug and
pharmacologic effects

RECEPTORS

4


Selective in choosing a drug molecule to bind
to avoid constant activation by promiscuous
binding of many different molecules

RECEPTORS

5

Changes its function upon binding in such a
way that the function of the biologic system
is altered in order to have pharmacologic
effect

RECEPTORS

6


Selective in ligand-binding characteristics
(respond to proper chemical signals and
not to meaningless ones)
Mediate the actions of both pharmacologic
agonists and antagonists

RECEPTORS

7

Majority are proteins which provide the
necessary diversity and specificity of
shape and electrical charge

RECEPTORS

8

Specific binding region of the macromolecule
High and selective affinity to the drug molecule

RECEPTOR SITE/RECOGNITION SITE

9


is the fundamental event that initiates the action
of the drug

Interaction between the drug and the receptor

10

CLASSIFICATION OF RECEPTORS

Best characterized drug receptors
Mediates the action of endogenous chemical
signals like neurotransmitters, autacoids and
hormones
Mediates the effects of the most useful
therapeutic agents

REGULATORY PROTEIN

11

CLASSIFICATION OF RECEPTORS

Inhibited (or less commonly, activated) by
binding a drug
Eg, dihydrofolate reductase, the receptor for
methotrexate

ENZYMES

12

CLASSIFICATION OF RECEPTORS

Eg, Na+/K+ ATPase, the membrane receptor
for digitali

TRANSPORT PROTEINS

13

CLASSIFICATION OF RECEPTORS

Eg, tubulin, the receptor for colchicine,
an anti-inflammatory drug

STRUCTURAL PROTEINS

14


Molecules that translate the drug-receptor
interaction into a change in cellular activity
Eg, adenyl cyclase

EFFECTORS

15


Response of a particular receptor-effector
system is measured against increasing
concentration of a drug
Graph of the response versus the drug
dose

GRADED DOSE-RESPONSE CURVE

16


Sigmoid curve
Efficacy (Emax) and potency (EC50) are
derived from this curve
The smaller the EC
50, the greater the
potency of the drug

GRADED DOSE-RESPONSE CURVE

17

Maximal response that can be produced
by a drug
All receptors are occupied
No response even if the dose is increased

Emax

18


Concentration of drug that produces
50% of maximal effect
Smaller EC
50–more potent

EC50

19

Total number of receptor sites
All receptors have been occupied

Bmax

20

Equilibrium dissociation constant
Concentration of drug required to
bind 50% of the receptors

KD

21

Measure of the affinity of a drug
for its binding site on the receptor

KD

22

Smaller KD

–greater affinity of drug to receptor

23

Transduction process between the occupancy
of receptors and production of specific effect
Highly efficient coupling can be elicited by a
full agonist and spare receptors

COUPLING

24


Maximal drug response is obtained at less
than maximal occupation of the receptors
Not qualitatively different from nonspare
receptors, not hidden or unavailable

SPARE RECEPTORS

25

Temporal in character, when occupied, they
can be coupled to respond, there is still effect
Drugs with low binding affinity for receptors
will be able to produce full response even at
low concentration

SPARE RECEPTORS

26


Compare concentration for 50% of maximal
effect (EC50) with concentration for 50%
maximal binding (KD)
KD > EC50 with spare receptors

SPARE RECEPTORS

27


Effect of the drug-receptor interaction may
persist for a longer time than the interaction
itself
Actual number of receptors may exceed the
number of effectors available

SPARE RECEPTORS

28


Non-regulatory molecules of the body
Binding with these molecules will result
to no detectable change in the function
of the biologic system

INERT BINDING SITES

29


Buffers the concentration of the drug
Bound drugs do not contribute directly
to the concentration gradient that drives
diffusion
Eg, albumin

INERT BINDING SITES

30

Binds to the receptor and directly or
indirectly bring about an effect
Full activation of the effector system

AGONIST

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