2-Pharmacodynamics & Drug Interaction

Front 1

Define Pharmacodynamics

Back 1

Study of what drugs do to the body and how they do it

Front 2

Discuss the 3 phases of the dose-response curve

Back 2

phase 1 = no measurable response
phase 2 = increased dose increases response
phase 3 = no further increase in response

Front 3

Define maximal efficacy

Back 3

Largest effect which can be produced by a drug

Front 4

Define relative potency

Back 4

Amount of drug needed to produce an effect. A potent drug produces effects at low doses

Front 5

The binding of a drug to a receptor does what to body processes?

Back 5

turns processes on or off

Front 6

How does a cell membrane-embedded enzyme work?

Back 6

Biding to the receptor on the cell membrane activates an enzyme inside the cell

Front 7

How do ligand-gated ion channels work?

Back 7

Binding to the receptor on the cell membrane activates the ion channels

Front 8

How do G protein-coupled receptors work?

Back 8

Binding to the receptor activates the G protein which activates the effector

Front 9

Where are transcription factors found? How do they work?

Back 9

On the DNA in the cell.
Activate transcription of messenger RNA to make protein

Front 10

Which type of receptor is the fastest?

Back 10

Ligand-gated ion channels

Front 11

Explain the simple occupancy theory of drug-receptor interaction

Back 11

The intensity of the response is determined by the number of receptors occupied

Front 12

Define affinity

Back 12

The strength of attraction between drug and receptor

Front 13

Define intrinsic activity

Back 13

The ability of the drug to activate a receptor after binding

Front 14

Define agonists

Back 14

Drugs which bind to the receptor and mimic the action of endogenous regulatory molecules

Front 15

Explain the actions of full and partial agonists

Back 15

Full agonists have high intrinsic activity and produce a full effect. Partial agonists have moderate intrinsic activity and produce a partial effect

Front 16

Define antagonists

Back 16

Drugs which bind to the receptor and block the action of endogenous regulatory molecules

Front 17

Explain the difference between competitive and noncompetitive antagonists

Back 17

competitive bind reversibly and maximal response can be achieved by increasing the concen of the agonist.
noncompetitive bind irreversibly and the maximal response cannot be achieved

Front 18

Explain up and down regulation

Back 18

Down regulation includes decreasing the number of receptors &/or response. Up includes increasing the number of receptors &/or response

Front 19

List 3 receptor-less drugs

Back 19

antacids, antiseptics, and saline laxatives

Front 20

Define the average effective dose (ED 50)

Back 20

Dose producing a therapeutic response in 50% of the population

Front 21

Define the therapeutic index. Is a large index safer or more dangerous?

Back 21

The ratio of the lethal dose to the average effective dose.
larger index = safer
smaller index = dangerous

Front 22

What is the relationship between the number of drugs a patient takes and the risk of drug-drug interactions?

Back 22

The more drugs the patient takes, the higher the risk of drug-drug interactions

Front 23

List 3 types of drug-drug interactions

Back 23

potentiative, inhibitory, unique

Front 24

How many laxatives affect absorption?

Back 24

Laxatives can decrease absorption by increasing drug passage

Front 25

Decreasing cardiac output may do what for drug excretion?

Back 25

Decrease drug excretion

Front 26

What organ system is responsible primarily for drug metabolism?

Back 26

Liver

Front 27

What happens to drug levels of drugs metabolized by the P450 system when the system is inhibited? induced?

Back 27

When metabolism is inhibited in the P450 pathway, drugs being metabolized by that pathway are not metabolized as rapidly and plasma drug levels increase. Conversely, when the system is induced, metabolism of those drugs occurs more rapidly, decreasing plasma drug levels

Front 28

What 4 processes happen with the induction of PGP (P-Glycoprotein)

Back 28

Decreased intestinal absorption, decreased fetal exposure, decreased brain exposure, increased elimination of drugs into bile or urine

Front 29

Calcium may do what to the absorption of tetracycline?

Back 29

Decrease absorption

Front 30

How does grapefruit affect the absorption of drugs from the intestines? How long does grapefruit exert this affect?

Back 30

Grapefruit inhibits CYP3A4 metabolism in the intestinal wall for 72 hours, so more drug is absorbed

Front 31

How would you administer a drug on an empty stomach?

Back 31

1 hr before eating or 2 hours after eating