Week 2 Pharmacodynamics and Pharmacokinetics

Question 1

What is pharmacokinetics?

Answer 1

What the body does to the drug!

• ADME
• Absorption, Distribution, Metabolism, Excretion

Question 2

What are 3 ways that drugs cross the cell membrane?

Answer 2

• Channels and pores (Small compounds)
• Transport systems (require energy and depends on drug structure)
• Direct Penetration (MOST COMMON)

Question 3

T/F Lipid soluble drugs can easily pass through the membrane?

Answer 3

True

Question 4

Ions and polar molecules?

Answer 4

Can not pass through cell membrane

Question 5

Absorption

Answer 5

-Movement of drug from it’s site of administration into the blood

Question 6

What are factors affecting absorption?

Answer 6

• Rate of dissolution (if a drug is liquid it dissolves quicker)
• Surface Area (larger the area the faster the absorption)
• Higher the blood flow the faster the absorption
• lipid solubility (the higher the faster it is absorbed)
• pH partitioning ( enhances when drug molecules can be ionized. Manipulate the environment to increase absorption)

Question 7

Routes of Absorption—– What types are Enteral?

Answer 7

Absorbed in the GI Tract (ORAL, Rectal)

Question 8

Routes of Absorption — What type are Parenteral?

Answer 8

IV, IM, SQ

Question 9

What are some local routes of absorption?

Answer 9

Topical, Transdermal, vaginal, inhaled, rectal, direct injection, intraosseous

Question 10

What is an enteric coated drug?

Answer 10

A drug that has an extra coating that protects the drug from the acidity of the stomach. Should not be chewed!

Question 11

What is a sustained release drug?

Answer 11

A drug where the formulation has been changed and is made to last longer.

Question 12

What is Distribution?

Answer 12

-Movement of drugs throughout the body

Question 13

Types of Distribution: Blood Flow to the Tissues

Answer 13

• drugs being carried by blood to the tissues since tissue is site of action.

Question 14

Types of Distribution: Exiting the Vascular system

Answer 14

• Drugs can normally pass through capillary cells.
  Exceptions are:
  BBB- due to tight junctions (neonates are vulnerable)
  Placenta- drug can cross placenta and can reach fetus
  Protein Binding: If a drug binds with protein it will stay in the drug! Only the amt that is free goes to site of action. Interactions with other protein bound drugs can cause one to be bound and one to be unbound. The unbound one can cause toxicity.

Question 15

Types of Distribution: Ability of the drug to enter cell

Answer 15

How it can cross cell membrane

Question 16

What is drug metabolism?

Answer 16

Enzymatic alteration of a drug

Question 17

Cytochrome P450 system

Answer 17

• 12 closely realted enzymatic families
• drug-drug interactions
• changes the drug

Question 18

What changes occurs with CYP450 System?

Answer 18

• Accelerated excretion, inactive, activation, decrease/increase toxicity, inducer, inhibitor

Question 19

What is the First Pass Effect?

Answer 19

Rapid hepatic inactivation of drugs!

• An oral drug goes to GI tract and goes directly to liver. Liver metabolizes drug.
• Decreases therapeutic response by inactivating a small portion of drug
• goes to system circulation

Question 20

Effects of the First Pass?

Answer 20

• Delays drug entry into blood stream
• lesser amount of drug in body
• this is why oral drug dose is higher
• does not apply to sublingual

Question 21

What organ plays a part in metabolism?

Answer 21

THE LIVER

Question 22

What is Excretion?

Answer 22

Removal of drugs from the body

Question 23

What organ plays a part in excretion?

Answer 23

The kidneys

Question 24

Where is can drugs be excreted?

Answer 24

Bile, sweat, saliva, breastmilk, skin, hair, tears, lungs

Question 25

3 mechanisms of the kidneys that are involved with excretion?

Answer 25

- GFR : Protein bound drugs affect this - Tubular resorption: lipid drugs move back into blood stream and avoid excretion - Active Tubular secretion: pumps drugs from blood back into urine.

Question 26

Drug Plasma Levels

Answer 26

- Used to regulate drug response | - a specific plasma level of drug must be achieved before therapeutic effects happen

Question 27

Minimum drug level

Answer 27

-Will not be high enough to elicit a response from patient

Question 28

Therapeutic Range

Answer 28

Narrow or broad range of desired response

Question 29

Toxic Drug level

Answer 29

too much drug in the body that causes harmful effects

Question 30

Single Dose Time Course

Answer 30

- Drug levels rise during absorption and distribution. Decline during metabolism and elimination.

Question 31

Drug Half Life

Answer 31

- Time for drug in body to decrease by 50% - More drug that's in larger amount is lot during half life - Half live can vary from mins- weeks

Question 32

Half life is a determinant of

Answer 32

- duration of action - time required to reach steady state - dosing frequency

Question 33

How many half lives does it take for a drug to become therapeutic in the body? For it to hit a plateau? For most of the drugs to be eliminated from the body?

Answer 33

4 half lives

Question 34

Plateau

Answer 34

-The amt of drug eliminated is equal to amt that is administered

Question 35

Loading Doses

Answer 35

Helps get a patient to a plateau much faster

Question 36

Repeated doses

Answer 36

Doses that are given that are influenced by rate of absorption and elimination

Question 37

What is a Peak Level?

Answer 37

Greatest concentration of drug in the blood. | -If level is too high? Hold dose and repeat blood draw

Question 38

What is the through level?

Answer 38

The lowest concentration of drug in blood

Question 39

What can you do based off of peak and through levels?

Answer 39

- Helps to change dose of medications | - Frequency of medication

Question 40

Pharmacodynamics

Answer 40

What drugs do to the body and how they do it?

Question 41

Dose Response Relationships

Answer 41

-As dosage becomes larger, response becomes larger -Efficacy :the largest effect a drug can produce. (Morphine has no ceiling versus Tylenol) -Potency: Dosage needed to produce effect (Dilaudid 0.3mg is more potent than Morphine 2.0mg)

Question 42

Receptors and Drug Selectivity of Drug Action

Answer 42

- The more selective a drug is, the fewer side effects it will produce. Does not equal safety - Each type of receptor participates in the regulation of a few processes - Drugs bound to receptors only mimic the body's natural functions - Lock and key matches only one receptor - Affinity- strength: How attracted is that drug to receptor. Drugs that have high affinity can bind to receptors when concentration is low - Intrinsic activity- ability to activate a receptor upon binding (related to max efficacy)

Question 43

Agonists

Answer 43

- Drugs that activate receptors and mimic the body's response. Results in process that goes faster of slower.

Question 44

Antagonists

Answer 44

- Block receptor activation. There is affinity but no intrinsic activity. No observable effect.

Question 45

Competitive Nonantagonist

Answer 45

- bind irreversibly to receptors | - effect is non reversible even if an agonist is added

Question 46

Competitive Antagonist

Answer 46

- bind reversibly with whatever agent is available in the highest concentration - effect is reversible if agonist is added

Question 47

Partial Agonists

Answer 47

- have only moderate intrinsic activity | - has both antagonist and agonist

Question 48

ED50

Answer 48

Effective dose required to produce a therapeutic response in 50% of the population.

Question 49

LD50

Answer 49

The does that is lethal to 50% of animals

Question 50

Therapeutic Index

Answer 50

- Highest does required to produce a therapeutic effect must be lower than the lowest dose to produce death. - The larger and higher the TI the more safe a drug is more distance.

Question 51

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Answer 51

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