Pharmacokinetics (Lectures 4-8 combined) Flashcards Preview

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Flashcards in Pharmacokinetics (Lectures 4-8 combined) Deck (51)
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1
Q

pharmacokinetics?

A

Quantitative analysis of drug movement into, throughout, and out of the body (Absorption, distribution, metabolism, excretion) ADME

2
Q

what is ion trapping?

A

an effect of ionization where a weak acid depolarizes after being absorbed so it gets trapped

3
Q

graph of IV bolus injection?

A

log plot

4
Q

Enteral?

A

oral, rectal, sublingual (GI)

5
Q

Parenteral?

A

not enteral, IV, IM, SC, topical, inhalation

6
Q

which is more absorptive? stomach or sm. intestine?

A

small intestine (can do weak acid and weak bases)

7
Q

chelation does what?

A

binding to metals make it hard to absorb

8
Q

how can you help acid sensitive drugs?

A

use coating so it can at least pass the stomach

9
Q

what is first pass metabolism?

A

drugs can get metabolized in intestine and liver before it even gets into bloodstream

10
Q

using SC or IM, is lipid or water soluble faster?

A

water soluble

11
Q

bioavailability is mathematically:

A

AUCoral/AUCiv=Fsmaller F means it is likely means given IV and not PO

12
Q

distribution:

A

REVERSIBLE transfer of drug from general circulation to other parts of the body

13
Q

Vd (volume of distribution)-

A

Dose(t0)/Plasma drug concentration

14
Q

High plasma drug concentration means…

A

low Vd

15
Q

Low plasma drug concentration means…

A

high Vd

16
Q

over 40 Vd means

A

drug is in tissue

17
Q

order of drug distribution between tissue?

A

VRG/blood, muscle, tissue

18
Q

albumin can do what to drugs?

A

keep them in the blood and not be eliminated

19
Q

metabolism?

A

drug goes from active to inactive

20
Q

excretion?

A

drug leaves body unchanged

21
Q

how to measure normal renal function? (filtration)

A

serum creatinine levels in blood (from muscle breakdown) of 1.0mg/dl

22
Q

secretion in kidney?

A

more efficient than filtration. active transporters for weak acids and weak basis.

23
Q

how is secretion related to drug elimination?

A

drugs can compete for transport so one drug can stay and the other may leave

24
Q

reabsorption in kidney?

A

urine to blood. opposite movement

25
Q

biotransformation meaning?

A

metabolism

26
Q

xenobiotic?

A

foreign substance that is introduced to body

27
Q

Phase I metabolism

A

small tweak. create or unmask chemically reactive functional group

28
Q

phase II metabolsim

A

adding more substrates or what not, bigger tweak

29
Q

metabolism can make drugs…

A

active, more active, inactivated, or toxic

30
Q

cytochrome p450 system

A

divergent family of mixed function oxidases, found largely in liver, also kidney, lung, intestine, and others(CYP3A4/5, CYP2C8/9, CYP2D6)

31
Q

how does CYP3A4 act on drugs?

A

substrate, inhibitor or inducer

32
Q

clearance is measured as…

A

volume / time

33
Q

elimination is measured as…

A

mass / time

34
Q

half life is measured as…

A

time

35
Q

first order elimination concept

A

process where elimination rate is directly proportional to the amount of drug in the body at any point in time. a CONSTANT FRACTION is eliminated at any given time

36
Q

high clearance relation to half life

A

inversely, high clearance means smaller half life

37
Q

Vd relation to half life?

A

directly, high Vd means longer half life

38
Q

two fundamental biological parameters

A

Vd and clearance

39
Q

when drugs are not first order>

A

still treat as first order

40
Q

pharmacokinetic compartment

A

volume of body fluids/tissues within which a drug is in rapid equilibrium

41
Q

central compartment 1

A

systemic circulation plus all fluids/tissues in RAPID equilibrium with the systemic circulation

42
Q

peripheral or tissue compartments

A

SLOW equilibrium with the systemic equilibrium

43
Q

every compartmental model has

A

compartment 1, and Ke (elimination), and drug input EXCEPT for IV bolus

44
Q

only compartment model that has no absorption process or input kinetics

A

IV BOLUS infusion

45
Q

what does IV bolus injection look like on a semi-log plot graph? and why?

A

negative linear slope (due to excretion)

46
Q

[Drug] equals

A

Dose/Vd

47
Q

Half life, t(1/2), equals…

A

(Vd/Cl)*0.693

48
Q

Bioavailability (F) =

A

AUCoral/AUCiv

49
Q

What does it mean when Bioavailability is 1?

A

all of the drug was absorbed

50
Q

why does the IV continuous infusion graph plateau?

A

the input rate is equal to the elimination rate (it finally caught up)

51
Q

Css (concentration at steady state) =

A

R0/Cl