Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Kinetics > E1 L9: Bioavailability and Clearance 4: > Flashcards

E1 L9: Bioavailability and Clearance 4: Flashcards

1
Q

When fe is 0

A

Hepatic clearance is the same as renal clearance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What directional changes in AUCiv and CL are expected

A

Decrease clearance, and increased AUCiv

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What directional changes in AUCpo and F are expected?
Decrease intrinsic decreased oral

A

Increased oral AUC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Q: Assuming 100% oral absorption, co-administration of an enzyme inducer with a low EH drug (Drug X) would:
A. Significantly increase F of drug X
B. Significantly decrease F of drug X
C. Significantly increase CLH of drug X
D. Significantly decrease CLH of drug X

A

C. Significantly increase CLH of drug X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Q: Assuming 100% oral absorption, co-administration of an enzyme inducer with a high EH drug (Drug Y) would:
A. Significantly increase F of drug Y
B. Significantly decrease F of Drug Y C. Significantly increase CLH of Drug Y
D. Significantly decrease CLH of Drug Y

A

B -significantly in decrease F of drug Y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Q: Assuming 100% oral absorption and fe = 0, co-administration of an enzyme inducer with a high EH drug (Drug Y) would:
A. Significantly increase Cl of Drug Y
B. Significantly increase CLpo of Drug Y
C. Significantly increase F of Drug Y
D. Significantly increase AUCiv of Drug Y

A

B. Significantly increase CLpo of Drug Y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Some drugs are eliminated unchanged in the urine. We can determine how much of a drug is excreted unchanged into the urine by collecting and analyzing urine concentration data

A

Renal excretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Approx. - of cardiac output goes to the kidneys; of the volume - is filtered in the glomerulus; this is the Glomerular filtration rate (GFR) (120ml/min)

A

20%; 10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Only (bound/unbound) drug is filtered

A

Unbound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Over 90% of the filtered volume is reabsorbed in the

A

Renal tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Filtration occurs in the

A

Glomerulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Filtration depends on

A

Molecular weight
and unbound drug concentration in plasma (fu)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Filtration equation

A

CLR = Fu * GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Secretion equation

A

CLR > fu * GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Reabsorption equation

A

CLR < fu * GFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Drug A PK parameters are as follows:
CL: 500 ml/min
fu: 0.95
fe: 1
Q: T/F:
1. Hepatic metabolism is a major elimination pathway
2. T/F; Significant reabsorption occurs

A

False - Hepatic is not major, it is minor (Fe = 1)
False - when you compare clearance (fe is 1, means clearance is the same as renal clearance)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Occurs in proximal tubule

A

Secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

T/F: secretion is an active carrier mediated process

A

True
Saturable; there are separate transporters for acids and bases from plasma into urine. In general, neutral drugs are not secreted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

If rate of excretion > rate of filtration, then infer that

A

secretion has occurred.

20
Q

Are good substrates for renal transporters and dissociate rapidly from plasma proteins so as not to limit secretion. Amount of secretion is dependent only on renal blood flow e.g. para-amino hippuric acid (ER ~1)

A

High renal excretion drugs (High ER)

21
Q

Are poor substrates for renal transporters; even through blood sits at the proximal tubule for ~30 seconds, transportation is the limiting step. Amount of secretion depends on unbound concentration of drug in blood and is independent of renal blood flow

A

Low renal excretion drugs (low ER)

22
Q

Secretion may depend on:

A

Plasma protein binding (fu)
Kidney blood flow

23
Q

Drugs actively secreted by the kidney: Acids

A

Penicillin’s
Probenecid
-Share same transporters cam compete with each other situation

24
Q

T/F: Passive process for exogenous products including drugs

A

True

25
Q

If rate of excretion < rate of filtration

A

Infer that reabsorption has occurred

26
Q

If CLR < fu * GFR, then

A

reabsorption has occurred (secretion may have occurred, but reabsorption is greater)

27
Q

Factors affecting renal reabsorption of drugs: properties of drugs and physiological factors:

A

Properties:
Polarity
Ionization
Physiological factors:
Urine flow
Urine pH

28
Q

Polar compounds (are/are not) best absorbed

A

Are not

29
Q

Ionized compounds (are/are not) best absorbed

A

Are not

30
Q

High plasma protein binding (increases/decreases) drug excretion

A

Decreases

31
Q

Faster urine flow (increases/decreases) drug excretion

A

Increases

32
Q

Urine pH can vary widely from

A

4.5 to 7.5 (average 6.3)

33
Q

Variations of Urine pH are due to forced

A

acidification/alkalization
Respiratory or metabolic acidosis/alaklosis and drugs

34
Q

Urine pH is mostly important for

A

nonpolar drugs that are weak acids (salicylates) or weak bases (amphetamine)

35
Q

Acidification of urine (decreased pH) promotes reabsorption of

A

weak acids and promotes CLR of weak bases

36
Q

Alkalization of urine (increased pH) promotes reabsorption of

A

Weak bases and promotes CLR of weak acid

37
Q

(Phenobarbital is a weak acid its renal elim is governed by reabsorption)
Q:
1. T/F: Pheno is more ionized in basic urine pH
2. Pheno’s renal absorption is less in basic urine pH
3. Pheno’s CLR would decrease upon urine alkanization

A
  1. True
  2. True - more drug ionized, less reabsorption
  3. False
38
Q

Q: For a patient with a phenobarbital I(aspirin) overdose, what drug can increase CLr most significantly

A

Acetazolamide (alkalize)

39
Q

T/F: Methamphetamine is more ionized in acidic urine vs basic

A

True

40
Q

T/F: Methamphetamines renal absorption is more acidic in urine pH

A

False

41
Q

T/F: Methamphetamine’s CLR would increase upon acidification

A

True

42
Q

Drug that is polar in its unionized form is not reabsorbed
Strong acids (pKa<3) and strong bases (PKa>12) are completely ionized over urine pH range, therefore undergo little reabsorption
Very weak acids (pka > 8) and very weak bases (pKa<6) will be unionized in the urinary pH range and will be reabsorbed in this range, resulting in low CLR and insensitive to pH, e.g. phenytoin (acid) propoxyphone (base)

A

Situations insensitive to urinary pH
(Effects of urine pH on CLR)

43
Q

GFR is influenced by

A

Filtration

43
Q

Urine flow rate is influenced by

A

Reabsorption

44
Q

Urine pH is influenced by

A

Reabsorption

45
Q

Renal transporters are influenced by

A

Secretion

Kinetics (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions