Brainscape's Knowledge GenomeTM

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


See full index

Pharma > Lec 8 > Flashcards

Lec 8 Flashcards

1
Q

The three major routes of elimination (clearance) are :

A

• Hepatic metabolism.
• Biliary elimination.
• Urinary elimination.

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

elimination processes decrease the plasma concentration exponentially . (T/F) ?

A

T

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

estimates the amount of drug cleared from the body per unit of time is called ?

A

Clearance (CL)

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

Total CL calculated as follows

A

CL= 0.7*Vd/ t1/2

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

Most drugs are eliminated according to zero-order kinetics . (T/F) ?

A

F—>( first-order kinetics)

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

aspirin in high doses, are eliminated according to ?

A

zero-order or nonlinear kinetics

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

Metabolism leads to production of products with ?

A

increased polarity, which allows the drug to be eliminated

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

the rate of drug metabolism and elimination is directly proportional to the concentration of free drug . This statement describe?

A

First-order kinetics (linear kinetics)

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

Constant fraction of drug is metabolized per unit of time (that is, with each half-life, the concentration decreases by 50%). (T/F) ?

A

T

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

With a few drugs the doses are very large such as :

A

● Aspirin.
● Ethanol.
● Phenytoin.

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

In the zero-order kinetics , the rate of drug metabolism = ?

A

Vmax

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

The enzyme is saturated by a high free drug concentration, and the rate of metabolism remains constant over time . This statement describe?

A

Zero-order kinetics (nonlinear kinetics)

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

The rate of elimination is constant and does not depend on the drug concentration in zero-order kinetics . (T/F) ?

A

T

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

The kidney cannot efficiently eliminate lipophilic drugs that readily cross cell membranes and are reabsorbed in the distal convoluted tubules. (T/F) ?

A

T

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

Lipid-soluble agents are first metabolized into more polar (hydrophilic) substances in the liver via two general sets of reactions mention them :

A

phase I and phase II

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

The function of Phase I Reactions is ?

A

Convert lipophilic drugs into more polar molecules by introducing or unmasking a polar functional group, such as –OH or –NH2.

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

Phase I Reactions Involve?

A

reduction, oxidation, or hydrolysis.

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

Phase I Reactions can’t increase, decrease, or have no effect on
pharmacologic activity. (T/F) .

A

F —>(May increase, decrease, or have no effect on pharmacologic activity) .

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

Phase I reaction have two forms, mention them:

A
  1. Involves P450 system
  2. Does not involve P450 system
20
Q

The phase I reactions most frequently involved in drug metabolism are catalyzed by ?

A

the cytochrome P450 system (also called microsomal mixed-function oxidases).

21
Q

The P450 system is important for:

A

● Metabolism of many endogenous compounds (such as steroids, lipids)
● For the biotransformation of exogenous substances
(xenobiotics).

22
Q

Why there are many different P450 isoforms ?

A

Because there are many different genes that encode multiple enzymes

23
Q

Four isozymes are responsible for the vast of P450-catalyzed reactions. They are:

A

• CYP3A4/5.
• CYP2D6.
• CYP2C8/9.
• CYP1A2.

24
Q

CYP2D6, in particular, has been shown to exhibit

A

genetic polymorphism

25
Q

CYP2D6 mutations result in very low capacities to metabolize substrates. (T/F) ?

A

True

26
Q

Clopidogrel is a prodrug that can be active metabolite through?

A

CYP2C19

27
Q

patients who are poor CYP2C19 metabolizers have a higher incidence of ?

A

Cardiovascular events (for example, stroke or myocardial infarction).

28
Q

Some individuals obtain no benefit from the opioid analgesic codeine, because ?

A

they lack the CYP2D6 enzyme

29
Q

Similar polymorphisms have been characterized for the CYP2C subfamily of isozymes . (T/F) ?

A

T

30
Q

chemicals not normally produced or expected to be present in the body, for example, drugs or environmental pollutants is called ?

A

Xenobiotics

31
Q

Xenobiotics may induce the activity of these enzymes . (T/F) ?

A

T

32
Q

The functions of these drugs( Phenobarbital, rifampin, and carbamazepine) are ?

A
  1. inc. CYP isozymes synthesis
  2. inc. some drugs metabolism
  3. reduced effect
33
Q

Consequences of increased drug metabolism include:

A
  1. Decreased Plasma Drug Concentrations.
  2. Decreased drug activity if the metabolite is inactive.
  3. Increased drug activity if the metabolite is active.
  4. Decreased therapeutic drug effect.
34
Q

The most common form of inhibition is through?

A

competition for the
same isozyme which leads to serious adverse events

35
Q

The effect of Omeprazole is .

A

inhibits three of the CYP isozymes responsible for warfarin metabolism —> accumulation Of warfarin —> increase anticoagulant effect—> bleeding

36
Q

Mention the inhibitors drugs :

A
  1. Omeprazole
  2. erythromycin
  3. ketoconazole
  4. ritonavir
37
Q

Grapefruit juice inhibits?

A

CYP3A4

38
Q

Grapefruit juice inhibits CYP3A4 which leads to :

A

higher conc. Of nifedipine, clarithromycin, and simvastatin

39
Q

Give me examples about phase I reactions that not involving the P450 system:

A

•Amine Oxidation (Oxidation of Catecholamines or Histamine)
•Alcohol Dehydrogenation (Ethanol oxidation)
•Esterases (metabolism of Aspirin in the liver)
•Hydrolysis (Procaine).

40
Q

phase II reactions consists of ?

A

conjugation reactions

41
Q

We have water-soluble compounds that are often therapeutically inactive , mention them:

A

((glucuronic acid )), sulfuric acid, acetic acid, or an amino acid .

42
Q

notable exception is morphine-6-glucuronide, which is less potent than morphine . (T/F) ?

A

F—> (more)

43
Q

Drugs already possessing an ?

A

–OH, –NH2, or –COOH group

44
Q

These group may enter phase II directly and become conjugated without prior phase I metabolism. (T/F) ?

A

T

45
Q

The highly polar drug conjugates are then excreted by ?

A

kidney or in bile

Pharma (8 decks)

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