Brainscape's Knowledge GenomeTM

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


See full index

Pharmaceutics Spring 2016 > Drug Absorption #2 > Flashcards

Drug Absorption #2 Flashcards

1
Q

T/F Passive diffusion is uni-directional

A

FALSE: can move in either direction (the concentration gradient determines which direction the molecule moves)

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

What are the 2 routes in which blood can diffuse?

A

intracellular(transcellular)

-paracellular

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

intracellular transport

A

molecules move directly through the membrane

-this is the most common

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

paracellular transport

A

molecules move between cells

-has a limiting factor (size of the molecules)

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

What is the limiting factor of paracellular transport?

A

the size of the molecule

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

T/F Carriers are typically proteins

A

TRUE

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

What are the 2 types of carrier mediated transport?

A
  • facilitated

- active

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

Carrier Mediated Transport (2)

A
  • are specific (only move one type of molecule)

- typically located in specific areas of the GI tract

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

T/F Carriers CAN NOT be saturated

A

FALSE; there are only a certain number of carriers, which means they can be saturated

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

T/F Carriers can be inhibited

A

TRUE

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

T/F Carrier transport is one direction

A

TRUE (mucosal side –> to the blood)

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

Which transport system requires ATP energy?why?

A

Active transport b/c it can occur from a region of lower concentration to higher concentration

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

metabolism

A

chemical altering of the drug molecule by the body

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

What is the effect of metabolites on bioavailability?

A

although metabolites are inactive–> they decrease bioavailbility because there would be a reduced amount of drug that would get to the site of action

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

efflux transporters (2)

A
  • going in the opposite direction than what we would like

- typically P glycoproteins

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

P glycoproteins (3)

A
  • energy driven
  • pump the drug back in the direction in which it came from
  • not as specific as carrier proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

_____ are thought to cause tolerance to cancer therapeutic agents

A

P glycoproteins

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

What would be the effect of P glycoproteins on the bioavailability of the drug?

A

it would DECREASE the bioavailability because its taking the drug molecules in the opposite direction than we want them to go–> not allowing them to ultimately get to the site of action

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

What part of the stomach is where most secretion occurs?

A

the middle of the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Antrum

A

holds material in the stomach to control how it moves to the pylorus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

T/F The stomach is very muscular

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the functions of the stomach? (4)

A
  • reservoir
  • site of the beginning of digestion
  • regulate the delivery of nutrients
  • bacteriostatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The secretion of ____ typically destroys the bacteria that make it to the stomach

A

HCl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the secretion cells in the stomach? (4)

A
  • mucoid cells
  • chief cells
  • parietal cells
  • g cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

mucoid cells

A

secrete mucus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

mucus provides ____ and ____ protection

A

chemical and physical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

chief cells

A

secrete pepsinogen (gets converted to pepsin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

____ begins the digestion process in the stomach

A

pepsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

parietal cells

A

secrete primarily HCl and intrinsic factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

intrinsic factors are necessary for…

A

absorption of B12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

G cells

A

secrete gastrin (which in turn controls the secretion of HCl)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

About ___L/day of fluids are secreted by the stomach

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Would you anticipate significant absorption from the stomach? Why?

A
  • no, almost no drug is absorbed by the stomach

- drugs do not stay in the stomach long enough and the stomach has a small surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Where is the site of most absorption of drug?

A

small intestine due to the large membrane surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the pH of the stomach? with food?

A

~ 1-2

food neutralizes the stomach–> pH goes up to around 4,5, or 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the 3 segments of the small intestine?

A
  • duodenum: connected to the pylorus (upper)
  • jejunum (middle)
  • illeum (lower)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

T/F Each segment of the small intestine have regional differences

A

TRUE. transporter proteins are located at specific sites in the intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What components help tribute to the large surface area of the small intestine?

A
  • folds of kerckring (increase 3x)
  • villi (increase 30x)
  • microvill (increase 600x)
39
Q

Bile:

Is stored in the _______; made by the _____

A

gall bladder; liver

gall bladder empties bile into the duodenum (ph ~6)

40
Q

Why does the pH change from 2 when it leaves the stomach and go up to 6?

A

bicarbonate ion–>neutralize acidic fluid that is emptying from the stomach

41
Q

What is the primary function of the large intestine? pH?

A

storage of waste; pH 5.5-7

42
Q

T/F There are vili present in the Large Intestine.

A

FALSE; no villi present leading to absorption being poorer

43
Q

_____ are present in the large intestine. What is a downfall of having this there?

A

microflora–> if a drug makes it to the large intestine it may destroy the bacteria that is already there and the bacteria could absorb the drug and metabolize it

44
Q

As pH varies from a weak acid or base… so does

A

the degree of ionization

45
Q

Summary of pH in GI tract

  • stomach (fasting)
  • stomach (fed)
  • duodenum
  • ileum
  • large intestine
A
  • stomach (fasting): less than 2
  • stomach (fed): 2-6
  • duodenum: 6-6.5
  • ileum: 7-8
  • large intestine: 5.5-7
46
Q

T/F Solids and liquids are emptied the same way from the stomach

A

FALSE; emptied differently

47
Q

What do you think is a major factor affecting stomach emptying?

A

food

48
Q

Fed mode of the stomach (3)

A
  • one type of pattern
  • regular, frequent contractions
  • grinding and mixing occurs as long as food is present
49
Q

_____ and ___ will empty from the stomach and leave in a FIRST order process

A

liquids and particles less than about 5-10 mm

50
Q

Liquids empty the stomach _____. High Volume–> _____

A

immediately; faster emptying

51
Q

_____ leave in a ZERO order process, it is converted at a ______ rate

A

solids; constant

52
Q

What are the 4 phases of the fasting mode in the stomach?

A

I: relaxation
II: increase in tone and activity (few contraction of different magnitudes)
III: strong contractions–> HOUSEKEEPER
IV: decline in activity

53
Q

The housekeeping stage of the fasting mode….

A

sweeps anything left in the stomach out

54
Q

How long does it take for material to move through the entire small intestine?

A

3-4 hours

55
Q

T/F Solution, pellets, and single units move through the small intestine at about the same rate

A

TRUE-> it does not depend on the presence of food

56
Q

Absorption _____ occur in the stomach–> but the ____ of emptying of the stomach does effect drug absorption

A

DOES NOT; RATE

57
Q

What factors affect gastric emptying? (11)

A
  • meal type
  • hydrogen ion concentration
  • volume
  • osmolality
  • emotional state
  • exercise
  • posture
  • age
  • gender
  • disease state
  • drug
58
Q

Fats, proteins, and carbs typically have _____ emptying if they are the same caloric value. The presence of these _____ emptying

A

same; decrease

59
Q

____ (food) have the greatest effect on emptying on a molar basis

A

fats: they are harder to digest

60
Q

hydrogen ion concentration:

_____ concentration in intestine will INHIBIT emptying

A

Increased

61
Q

Volume:

____ volume of liquid results in more RAPID emptying

A

increased; liquids in general empty very fast. they can empty even when there is food in the stomach (takes about 12-15 minutes)

62
Q

Osmolality:

_____ contents empty FASTER than _____ liquids

A

iso-osmotic; hyper-osmotic

63
Q

T/F There are receptors in the duodenum that detect increases in the osmotic pressure that use feedback mechanism

A

TRUE

64
Q

_____ increases osmotic pressure

A

eating/food

65
Q

Emotional state:
_______: increases gastric emptying
_______: decreases gastric emptying

A

aggression- increase

stress, anxiety- decrease

66
Q

Exercise:
________: have no effect or slight increase in gastric emptying
_________: decrease gastric empyting

A

moderate intensity; vigorous

67
Q

Posture:
If you are on your ____ side: increase gastric emptying
If you are on your _____ side: decrease gastric emptying

A

right;left

68
Q

T/F Gastric emptying is FASTER in older people

A

FALSE: SLOWER

69
Q

T/F Females have slower gastric emptying then males

A

TRUE

70
Q

What disease states INCREASE gastric emptying? (3)

A
  • hyperthyroidism
  • duodenal ulcers
  • cholecystitis (inflammation of the gallbladder)
71
Q

Gastritis, GERD, Gastric Carcinoma, Pyloric stenosis, Gastric Ulcers, Diabetic Gastroparesis, Hypothyroidism, Migraine, Pregnancy_______ gastric emptying

A

decrease

72
Q

What drugs DECREASE gastric emptying? (4)

A
  • narcotic analgesic
  • isoniazid–> used to treat TB
  • antacids
  • tricyclic antidepressants
73
Q

What drugs INCREASE gastric emptying? (2)

A
  • metoclopramide

- erythromycin

74
Q

T/F Food has a great impact on gastric emptying

A

TRUE: general you would want a patient to take solid dosage form on an empty stomach with a full glass of water

75
Q

Why do we want to get the drug out of the stomach ASAP?

A

because it is not being absorbed in the stomach and it needs to get in the intestine

76
Q

What is considered an empty stomach with food?

A
  • 30 minutes before a meal

- 2 hours after a meal

77
Q

Why do some drugs need to be taken with food? (2)

A
  • if drug is irritating

- food increase absorption of some drugs

78
Q

T/F You CAN NOT decrease saturation if given with food

A

FALSE: you can

79
Q

How could food affect absorption of a drug? (3)

A
  • emptying
  • change in pH
  • interact with drug
80
Q

Food ____ gastric emptying

A

slows

81
Q

Food changing the pH could do what?

A
  • increase/decrease absorption

- increase/decrease degradation

82
Q

When the drug Nitrofurantoin was given with food, more excretion (unchanged drug) occurred. Why?

A

When you give with food emptying is SLOWED making the drug stay in the stomach longer which allows more of the drug to dissolve in the stomach before it is emptied into the intestine

83
Q

T/F Blood flow is static.

A

FALSE: there is first blood flow through the membrane then the drug is being carried away by the blood

84
Q

rate limiting step

A

slowest step in the overall process that controls how fast the process will proceed

85
Q

perfusion rate limited (2)

A
  • blood flow step is the slowest step (#2)
  • drug freely passes through the membrane with little resistance
    ex. water and ethanol
86
Q

diffusion or permeability rate limited

A
  • difficult to cross the membrane, slowly crosses the membrane
    ex. ribitol (large polar molecule)
87
Q

When a drug is administered through the muscle (IM), then it only has to cross…..

A

the blood capillaries

88
Q

Capillary walls are very ______ compared to the GI tract. What type of rate limited is this?

A

permeable

  • molecules with HIGH molar weights easily cross the capillary wall
  • perfusion rate limited
89
Q

Would you expect gentamicin, a large polar water soluble molecule to be absorbed well?

A

NO, because it is big and its polar but if administered into muscle tissue it is readily absorbed

90
Q

The vascularity in the SQ tissue is less than that of muscle tissue, what would you expect to be the effect on absorption?

A

SQ would have a slower rate of absorption because of less blood flow

91
Q

SQ administration: What would be the expected effect on the absorption rate following SQ administration in the following situation?

Application of heat or massage the site of administration

A

INCREASE because blood flow is increasing

92
Q

o SQ administration: What would be the expected effect on the absorption rate following SQ administration in the following situation?

Co-administration of a vasodilator or hyaluronidase (destroy connective tissue)

A

INCREASE, vasodilator because blood flow is increasing

hyaluronidase will cause the drug to spread out (increasing the SA)

93
Q

o SQ administration: What would be the expected effect on the absorption rate following SQ administration in the following situation?

Co administration of epinephrine that produces vasoconstriction

A

DECREASE

94
Q

Feedback mechanism in the duodenum (3)

A
  • receptors located in the duodenum, but control emptying in the stomach
  • an increase hydronium ions cause SLOW rate of emptying
  • osmotic pressure is related to colligative properties

Pharmaceutics Spring 2016 (20 decks)

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