PK/PD

Question 1

Down and dirty: What is pharmacodynamics?

Answer 1

How a drug affects the body.

Question 2

Down and dirty: What is pharmacokinetics?

Answer 2

How the body affects a drug.

Question 3

4 aspects of PK?

Answer 3

ADME:
A- absorption
D- distribution
M- Metabolism (or biotransformation, don't let that term trick you up)
E- Excretion (or elimination)

Question 4

What the heck does ‘chiral’ mean?

Answer 4

Describes the possibility of stereoisomerism/ enantiomerism in a molecule; also describes the carbon atom around which such isomerism may exist.Also, you can think of it as a Carbon with 3 or 4 different elements attached to it.

Question 5

What is an enantiomer?

Answer 5

A molecule that exhibits chirality; enantiomers of each other have the same chemical makeup, but on a carbon, things are arranged differently such that two enantiomers are mirror images of each other without being able to be superimposed on each other (right hand and left hand)

Question 6

Similarities between enantiomers?

Answer 6

Same physical properties: molecular weight, boiling/freezing points, etc. Similar chemical properties: combustion, etc.

Question 7

Enantiomers are either _____- or _____-rotatory.

Answer 7

levo- dextro- (remember that this has to do with their ability to polarize and rotate light when dissolved in a solution)

Question 8

How do enantiomers differ?

Answer 8

Absorption, distribution, clearance, potency, and toxicity.

Question 9

What does racemic mean?

Answer 9

Combo of levo and dextrorotatory forms of molecules

Question 10

Common racemic drugs?

Answer 10

Racemic epi
fluoxetine
warfarin
ibuprofen
omeprazole
atenolol
atropine
thiopental
ketamine
NMBs
Local anesthetics
Opioids

Question 11

Define: hyperactive

Answer 11

Describes person in whom an expected effect is achieved with a lower-than-normal dose

Question 12

Define: hypoactive

Answer 12

Describes a person in whom a higher-than-normal dose is required to achieve an expected effect

Question 13

Define: tolerance

Answer 13

When an increasing dose is required to achieve the same effect. If this happens rapidly, it is known as tachyphylaxis.

Question 14

Define: idiosyncrasy

Answer 14

unexpected unusual effect

Question 15

Define: additive effect

Answer 15

drugs added together achieve a larger effect (1+1=2)

Question 16

Define: synergistic effect

Answer 16

drugs added together achieve a much larger result (1+1=384)

Question 17

Define: ligand

Answer 17

molecule that interacts with or bonds to a receptor

Question 18

Define: antagonism

Answer 18

the binding of a chemical to a receptor in such a way that no effect is produced

Question 19

Define: agonism

Answer 19

a chemical binds to a receptor and elicits a response from said receptor

Question 20

Define: competitive antagonism

Answer 20

increasing concentrations of antagonists progressively inhibit the response to an unchanging concentration of an agonist

Question 21

Define: noncompetitive antagonsim

Answer 21

when even at high doses, an agonist cannot overcome antagonism

Question 22

What is bioavailability?

Answer 22

The amount of active drug that remains in circulation after first-pass metabolism

Question 23

What is volume of distribution (Vd)?

Answer 23

A number that expresses how much of a drug is distributed out of the circulation; the larger the number, the more extensive the distribution is.

Question 24

What is clearance?

Answer 24

The amount of plasma that is cleared of a drug.

• Hepatic
• Biliary
• Renal

Question 25

First-order kinetics. What is that?

Answer 25

A constant FRACTION is cleared in a given time

Question 26

Zero-order kinetics. What do that be?

Answer 26

A constant AMOUNT is cleared in a given time

Question 27

Elimination half-time v. context-sensitive half-time

Answer 27

Elim T1/2: time needed for [plasma] of drug to decrease by 50% during elim. phase

CS T1/2: time needed for [plasma] to decr by 50% after d/c continuous infusion

Question 28

Number of elimination half-times needed to clear a drug?

Answer 28

~5 half-times:
T1/2 Fraction remains % cleared
0 1 0
1 1/2 50
2 1/4 75
3 1/8 87.5
4 1/16 93.8
5 1/32 96.9
6 1/64 98.4

Question 29

Think about a two-compartment model… What is the first (central) compartment?

Answer 29

Vasculature, vessel-rich organs (brain, lungs, heart, kidneys, liver)

Question 30

Think about that two compartment model again… What is the second (peripheral) compartment?

Answer 30

Collectively the fat, muscle, and vessel-poor groups.

Question 31

Factors affecting distribution between compartments…

Answer 31

Age (higher [plasma])
Residual drug
Lipid solubility of drug
Elimination rate