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Flashcards in PK/PD Deck (31)
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1

Down and dirty: What is pharmacodynamics?

How a drug affects the body.

2

Down and dirty: What is pharmacokinetics?

How the body affects a drug.

3

4 aspects of PK?

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

4

What the heck does 'chiral' mean?

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.

5

What is an enantiomer?

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)

6

Similarities between enantiomers?

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

7

Enantiomers are either _____- or _____-rotatory.

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

8

How do enantiomers differ?

Absorption, distribution, clearance, potency, and toxicity.

9

What does racemic mean?

Combo of levo and dextrorotatory forms of molecules

10

Common racemic drugs?

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

11

Define: hyperactive

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

12

Define: hypoactive

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

13

Define: tolerance

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

14

Define: idiosyncrasy

unexpected unusual effect

15

Define: additive effect

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

16

Define: synergistic effect

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

17

Define: ligand

molecule that interacts with or bonds to a receptor

18

Define: antagonism

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

19

Define: agonism

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

20

Define: competitive antagonism

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

21

Define: noncompetitive antagonsim

when even at high doses, an agonist cannot overcome antagonism

22

What is bioavailability?

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

23

What is volume of distribution (Vd)?

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.

24

What is clearance?

The amount of plasma that is cleared of a drug.
-Hepatic
-Biliary
-Renal

25

First-order kinetics. What is that?

A constant FRACTION is cleared in a given time

26

Zero-order kinetics. What do that be?

A constant AMOUNT is cleared in a given time

27

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

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

28

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

~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

29

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

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

30

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

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