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Flashcards in Pharmacodynamics Deck (14):
1

Basic Definition of Pharmacology and toxicology:

A. Pharmacology refers to the study of substances that interact with living systems through chemical processes
B. Toxicology is viewed as a branch of pharmacology with deals with adverse effects

2

Two functions of a drug receptor:

1. Recognition - the receptor binds a drug or endogenous ligand

2. Transduction - transfer of information

3

Describe Recognition, Selectivity, and Specificity of drug receptors.

A. The ability of a drug to bind with a receptor depends on the "goodness of fit" of drug to the receptor. This requirement for the receptor to recognize and bind a drug provides the basis for selective action at one or a small number of receptor sub-types.

B. The hundreds of different receptors types and their unique tissue localization impart specificity of drug action; that is, the ability of a drug to exert a distinctive influence on the body.

C. Proteins, which include enzymes, transporters, ion channels, structural proteins, and regulatory proteins, represent the majority of drug receptors.

4

What is transduction by cell receptors?

The interaction of a drug with its receptor propagates a signal, i.e. it converts the “drug signal” into a tissue response.

5

What are four common drug receptor mechanisms?

1. G protein coupled receptors (GPCRs)
-most common; regulate 2nd messengers like cAMP, IP3, ect.

2. Modulate ligand-gated ion channels (both cationic & anionic)

3. Intrinsic enzyme activity phosphorylates diverse effector proteins

4. Regulation of gene transcription

6

Two potential attributes of receptor mediated processes that can lead to durg-drug interactions:

1. organization into opposing systems

2. Many receptors utilize a pool of relatively few 2nd messengers

7

What is the general idea of the Occupancy Theory?

drug + receptor drug receptor complex --> effect

or

X + R RX, where the forward association constant is k1 and the reverse reaction dissociation constant is k2

8

Define Potency.

a comparative term used to describe the relative positions of several agonist dose-response curves

the curve to the left (lower dose to cause effects) is more potent, it does NOT mean it has a higher maximum effect

9

a drug capable of inducing a maximum response, it has full efficacy (α = 1) is called:

full agonist

10

a drug whose maximal response is only a fraction of the maximum that can be elicited, it has partial efficacy (1 > α > 0)

partial agonist

11

a drug which inhibits the action of an agonist is an:

antagonist

A “pure” antagonist is a drug that can bind to a receptor, i.e. it has affinity for the receptor, but induces no response, i.e. it has zero efficacy (α = 0).

12

In the presence of a competitive antagonist, the agonist dose-response curve shifts to the_________. The slope of the curve________.

right, does not change

13

In the presence of a noncompetitive antagonist the maximal response of an agonist is______, and the slope of the curve is________.

reduced, reduced

14

An Inverse agonist is a drug that preferentially binds to the _______ form shifting equilibrium to the ________ form. This results in an effect _______ of that produced by an agonist.

inactive, inactive, opposite