[6] Pharmacokinetics

Question 1

Definition: Pharmacokinetics

Answer 1

Effect of the body on the drugs

kinEtics : admE (Absorption, Distribution, Metabolism, Excretion)

Question 2

Routes of Administration

Answer 2

Enteral

Parenteral

Question 3

Examples of Enteral Administration

Answer 3

Oral
NGT
Gastrostomy Tube

Question 4

Examples of Parenteral Administration

Answer 4

Intravenous
Intramuscular
Subcutaneous
Intradermal
Topical

Question 5

[Better or Worse Arbsorption]

Non-Ionized

Answer 5

Better

Question 6

[Better or Worse Arbsorption]

Small Molecules

Answer 6

Better

Question 7

[Better or Worse Arbsorption]

Lipid-Soluble

Answer 7

Better

Question 8

[Better or Worse Arbsorption]

Ionized

Answer 8

Worse

Question 9

[Better or Worse Arbsorption]

Large Molecules

Answer 9

Worse

Question 10

Dopamine and Serotonin penetrate brain tissue poorly, however these precursors enter with relative ease.

Answer 10

L-Dopamine

5-Hydroxytryptophan

Question 11

Used to treat Parkinson’s Disease

Answer 11

L-Dopa

Question 12

Define: Volume of Definition

Answer 12

Hypothetical Volume

Not the same as PV, BV, Interstitial Volume, Intracellular Volume, Extracellular Volume

Question 13

Formula: Volume of Distribution

Answer 13

Dose Administered / Concentration

Question 14

[T/F] If Drug X is metabolized into an inactive metabolite and this inactive metabolite is excreted by the kidneys, the mode of elimination is both metabolism and excretion

Answer 14

X

Question 15

Define: Phase I Reactions

Answer 15

Functionalization Reactions

Oxidation, Reduction, and Hydrolytic Reactions

Question 16

Define: Phase II Reactions

Answer 16

Conjugation Reactions

Conjugated to polar groups:

Glucorinidation, Sulfation, Acetylation

Question 17

What is the initial molecule for hormones?

Answer 17

Cholesterol

Question 18

Which cytochromes handles the most of P450 Metabolism?

Answer 18

CYP3A4 (50%)

Recent data says it’s about 33%

Question 19

How long does it take for an inhibitor to take effect?

Answer 19

About a week

Question 20

Is Grapefruit Juice an inhibitor?

Answer 20

Yes, a yummy one.

Question 21

Define: Phase 3 Metabolism

Answer 21

Not metabolism perse, no biotransformation occurs.

This is a transporting “phase”

Question 22

What kind of a pump is P-Glycoprotein?

Answer 22

Efflux Pump

Question 23

Define: Enterohepatic Recirculation

Answer 23

Compound is conjugated in the liver
Excreted in the bile
Deconjugated in the intestine
Reabsorbed in circulation

Question 24

Physiologic Significance of Enterohepatic Recirculation

Answer 24

95% of Bile Salts are reabsorbed and used for cholesterol synthesis

Allows for the prolonging of duration of action of a drug

Question 25

Excretion of drugs by the liver is usually through?

Answer 25

Biliary excretion

Question 26

Differentiate: Metabolism and Excretion

Answer 26

When a drug is excreted, it is untouched not a metabolite form

Question 27

What are the main assumptions of the One Compartment Model?

Answer 27

1. Body is a single process
2. Drug distribution is instantaneous
3. Equilibrium exists between blood and tissues
4. Instantaneous and well-mixed

Question 28

What are the main assumptions of the Multi Compartment Model?

Answer 28

1. Drug distribution is instantaneous in compartments but between them they may not be the same
2. Drug distribution is not instantaneous

Question 29

Half Life Concentration of Drugs

Answer 29

t(1/2) = 0.693/k

Question 30

What happens to the half life of the drug if the clearance is decreased by 50%?

Answer 30

T1/2 is Doubled

Question 31

How long will it take for a drug to reach one-fourth of its present concentration?

Answer 31

2 Half Lives