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Flashcards in Pharmacodynamics Deck (54):
1

Radioactive Iodine

Iodine is actively concentrated in the thyroid and the radiation will destroy all tissue within 2-3mm causing focal, controlled destruction

2

How does down regulation of receptors occur?

Internalizing the receptors in lysosomes, recycling them, sequestering or degrading.

Part of normal cellular metabolism 

Tolerance

Tachyphylaxis

3

Down Regulation of Receptors

Number of receptors decreases and therefore a reduction in the effect

4

Full Agonist

Binds to the receptor to elicit a maximal response

5

Examples of non receptor biological reactions

Voltage Gated Channels

Enzymes

Carrier Proteins

6

Targets for drug reaction are divided into what two categories

Physical Interactions

Biological Interactions

7

Common receptor for secretory and smooth muscle functions whre the changes occur over seconds.

Metabotropic Receptors

8

Nonspecific drug effects occur in (physical/biological) interactions

Physical Interactions

9

Examples of nonspecific drug effects

Osmotic Diuretics

Antacids

Radioactive Iodine

10

Drug effects on Voltage Gated Channels

Blocking of ion channels can occur by the drug moleucle physically obstructing the channel to impair ion movment.  Drug may also modulate the opening/or closing of the channel

11

The straight portion of the sigmoidal drug response curve falls between what range?  This corresponds to what?

20-80%

Therapeutic Range

12

Ionotropic Receptors

13

Steroids and thyroid hormones are examples of what type of receptor, new protein production starts over the course of hours

Nuclear Receptors

14

Mixed Agonist - Antagonist

Acts as an agonist in one type of receptor and as an antagonist on other types of receptors

15

Side Effects

Secondary to the intended effect and may be good or bad

16

Agonist

Mimics the effect of the endogenous ligand

17

Toxic Effects

Responses to a drug that are harmful to the health or life of the animal

18

Efficacy

Maximal effect a drug can have

19

Types of pharmacodynamic receptors

Ionotropic Receptors

Metabolic Receptors

Kinase-Coupled Receptors

Nuclear Receptors

 

20

Antacids (Direct Neutralizers)

Given orally they direct interact with acid in the GI tract, a form of physiologic antagonism

21

Drug effects on Enzymes

Drugs can be analogs that compete with the real substrate for binding to the enzyme, prodrugs where the drug needs to be metabolized into its active form or can act as false substrates which will lead to the formation of abnormal metabolites instead of active product.

22

Lethal Dose 50 (LD50)

Dose which kills 50% of animals

23

Ceiling effect

A partial agonist may never be able to achieve full efficacy

24

Osmotic Diuretics

Molecules move through the body dragging water with them by osmosis until they are excreted

25

Partial Agonist

Will bind to the receptor but not cause as much effect as a full agonist, it does prevent anything else from binding to the receptor while docked there

26

Effective Concentration 50 (EC50)

Concentration at which a drug produces 50% of its maximal effect, only applies to in vitro preparations useful to compare the efficacy of different ligands

27

Onset of Action (Latent Period)

Time required after drug administration for a response to be observed

28

T/F: Endogenous neurotransmitters often bind to more than one type of receptor.  The same signaling molecule can then cause different effects or have different affinity in different tissues or species.

True

29

A low therapeutic index indicates a (safe/dangerous) drug

Dangerous

30

Chemical Antagonism

Two drugs chemically inactivate each other

31

Therapeutic Effects

Effects that clinicians want

32

Quantification of drug response typically gives what type of curve when plotted on semi-log paper

Sigmoidal Curve

33

Drugs can bind and activate or prevent from opening, often involved in fast neurotransmission.

Ionotropic Receptors

34

Adverse Effects

Unintended and unwanted, this includes not producing the clinical effect

35

Insulin receptors and growth promoting hormones and factors are of these type of receptors.

Kinase-Coupled Receptors

36

Therapeutic Index

Ratio of LD50 and ED50

37

Potency

Comparison of the concentratio of two drugs needed to induce the same magnitude effect

38

Up Regulation of Receptors

Increase in the number of receptors, resulting in increase in the effect of drug

39

Duration of Action

Length of time that a drug is effective - from onset of action until termination of action

40

Nuclear Receptors / Transcription Factor Receptors

 

Located in the cytoplasm but after ligand binds translocate to the nucleus of the cell and bind to a response element within the DNA to initiate specific gene transcription

41

Pharmacodynamics

Efects of drugs and their mechanism of action within the body

42

Drug effects on Carrier Proteins

Some small, polar molecules cannot cross cell membranes and get carried in and out by carrier proteins.  Drugs may alter this movement either preventing re-uptake of a molecule which increases its levles or preventing output of a molecule to decrease its levels

43

Pharmacokinetic antagonsim

Drug alters ADME of another drug and reduces its effect

44

Antagonist - Neutral Agonist

Binds to the receptor but does nothing on its own, however it sits and prevents anything else from binding and thus blocks the receptor

45

Non-Competitive Antagonism

Ligand that interacts somewhere other than the receptor but causes a change in the receptor that blocks its ability to bind to the normal ligand

46

A high therapeutic index indicates (safe/dangerous) drug

Safe

47

Kinase-Coupled Receptors

Transmembrane proteins have an extracellular receptor portion and an intracellular portion that has enzymatic activity.  Phosphorylation and activation of proteins activate effectors

48

Physiologic Antagonism

Drugs have opposite effects that cancel each other out

49

Ligand

Anything that binds to a recognition site 

50

Competitive Antagonism

Antagonist ligand binds and releases as long as it is present and so if the antagonist is present as well as an agonist they will compete for the binding, who binds more often will  be determined by the concentration and affinity

51

Metabotropic Receptors

G protein receptors (7TM) receptors, transduce an extracellular signal to an intracellular one by activating the G-Protein second messanger system

____________________

Allow for signal amplification and specificity

52

Biological interactions include

Receptors

Non Receptors

53

Effective Dose 50 (ED50)

Dose that produces a result (usually desired) in 50% of the animals

54

Reverse Agonist

Will bind to the receptor and cause the opposite effect as the endogenous ligand would