Introduction to Pharmacokinetics

Question 1

Name the four stages a drug may go through after introducing it into a patient.

Answer 1

1. Absorption
2. Distribution
3. Metabolism
4. Elimination

Question 2

A process of absorption that does not require energy and cannot proceed against gradients.

Answer 2

Passive (Diffusion) Absorption

Question 3

Filtration and Diffusion are under which of the 4 stages?

Answer 3

Absorption (Passive)

Question 4

When combining the ionized and the unionized form of drugs together, what should the total percentage add up to?

Answer 4

ALWAYS 100%

Question 5

Differentiate between Ionized and Unionized Compounds.

Answer 5

Ionized: DO NOT easily cross the lipid bilayer and are not readily reabsorbed; Therefore they are typically ELIMINATED

Unionized: EASILY cross the lipid bilayer and can be reabsorbed readily; Therefore, they are typically NOT ELIMINATED

Question 6

The ionization status depends on which 2 factors?

Answer 6

1. pka

2. pH

Question 7

What are two important areas in the body where the pH changes drastically?

Answer 7

1. GI Tract

2. Kidneys

Question 8

What is the ratio of “ionized:unionized” when the pka=pH?

Answer 8

50%:50% Ratio

Question 9

Energy Requiring, Saturable and Movement against gradients are all characteristics of which of the 4 stages?

Answer 9

Absorption (Active)

Question 10

True or False. Facilitated Transport is considered active transport.

Answer 10

TRUE

Question 11

What’s the big difference between Absorption and Distribution?

Answer 11

PROTEIN BINDING (within distribution)

Question 12

What does alpha represent when talking about protein binding?

Answer 12

Unbound Fraction (% of free drug in the body)

Can also be used as the availability of the drug to give pharmacological action

Question 13

Biotransformation/the ways the body uses to increase the likelihood of drug elimination from the body is the main goal of which process?

Answer 13

Metabolism (adMe)

Question 14

Which drug is extensively metabolized into 2 metabolites with 100% and 25% Potency?

Answer 14

Lidocaine

Question 15

Which phase of Biotransformation is responsible for formation of new or modified functional group or cleavage of chemical groups (i.e. Oxidation, Reduction, Hydrolysis Rxns)?

Which enzyme is mainly used?

Answer 15

PHASE 1

CYP450 is mainly used

Question 16

A compound that requires an isoenzyme (i.e. CYP450) to be metabolized is a __________ .

Answer 16

Substrate

Question 17

1. _________ prevent the enzyme from processing substrates.

2. _________ aid the enzyme in processing substrates.

Answer 17

1. Inhibitors

2. Inducers

Question 18

1. Use ________ to stop an active drug from getting metabolized into an inactive compound.
2. Use _________ to help an inactive prodrug metabolize into an active compound.

Answer 18

1. Inhibitors

2. Inducers

Question 19

What are reactions that involve conjugation (covalent linkages; Glucuronidation, Sulfation, Acetylation) with an endogenous substance?

Answer 19

Phase 2

Question 20

Drugs that are ingested orally need to first go through the portal circulation to the liver. This is an example of which phenomenon?

Answer 20

First Pass Effect

• ** Atenolol is NOT metabolized at all by the liver
• ** Propranolol is almost ENTIRELY metabolized by the liver

Question 21

List the primary routes of elimination of drugs (3).

Answer 21

1. Lungs
2. Skin (sweat)
3. Bile/Feces

Question 22

What are the three main processes of elimination in the kidneys (in relation to active vs. passive)? What do you need to do if these processes are disturbed?

Answer 22

1. Passive Glomerular Filtration
2. Passive Tubular Diffusion
3. Active Tubular Secretion

*** Might need to change the dose if the renal function has decreased!

Question 23

The fraction of the total amount of change in the Cp remains constant over time is an example of which pharmacokinetic property of drugs?

Answer 23

First-Order

Question 24

The fraction of the total amount of change in the Cp is not constant over time is an example of which pharmacokinetic property of drugs?

Answer 24

Zero-Order

Question 25

The time that is takes to reach Cmax is represent by which function on a graph?

Answer 25

Tmax

Question 26

The dose of a drug is represent by which function on a graph?

Answer 26

Cmax

Question 27

The frequency of a dose is represented by which function on a graph?

Answer 27

Cmin

Question 28

Maximum Therapeutic Concentration (MTC) - Minimum Effective Concentration (MEC) will equal what?

Answer 28

Therapeutic Range

Question 29

When do we consider that a drug is eliminated from the body in % and half-lives?

Answer 29

90% or 4-5 Half-Lives

Question 30

How many half lives does it take to reach the steady state?

Answer 30

4-5 Half-Lives

Question 31

What is the Tau of a continuous infusion?

Answer 31

1

Question 32

What is the term that represents the fraction of a dose that enters circulation?

Answer 32

Bioavailability

Question 33

Dose, Bioavailability (F) and Salt Factor (S) are going to determine ___________ .

Answer 33

Amount of Drug Absorbed

Question 34

Which term represents the numerical extent of drug distribution?

Answer 34

Volume of Distribution (Vd) Bigger Value = Larger Body-Distribution

Question 35

Which term represents the volume of blood per unit of time that is cleared of drug?

Answer 35

Clearance

Question 36

Which term represents a 'rate' of drug eliminated, described as a percentage of drug removed per unit time?

Answer 36

Elimination Rate Constant (Kel)

Question 37

Which term represents time required for 50% of drug to be eliminated?

Answer 37

Half-Life

Question 38

Which term represents an equilibrium between drug and body? Rate In = Rate Out

Answer 38

Steady State (Cpss)