Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pharmacology, exam 1 > Pharmacokinetics I (Absorption & Distribution) > Flashcards

Pharmacokinetics I (Absorption & Distribution) Flashcards

(68 cards)

Start Studying
1
Q

What is the ADME acronym?

A

Absorption
Distribution
Metabolism
Excretion

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

For most drugs, the concentration of drug at its site of action will be related to . . .

A

the concentration of drug in the systemic circulation

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

On what measurement does clinical pharmacokinetics heavily rely? Why?

A

Plasma drug concentrations, prediction of therapeutic and/or toxic effects of drugs

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

What is the therapeutic range on a concentration vs. time graph?

A

The area above the minimum effective concentration, but below the maximum tolerated concentration

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

Clinical significance of the AUC

A

Used to compare the amount of drug that reaches the systemic circulation by different routes of administration (bioavailability), as well as comparison of clearance between individuals given the same dose

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

What kind of relationship do clearance and AUC have?

A

Inverse

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

Definition of drug absorption

A

Processes by which drugs move from their site of administration to the plasma

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

Two processes of drug absorption following oral administration

A
  • Disintegration of solids and dissolution of drug in fluids of gastrointestinal tract
  • Passage of drug across or between cells to reach the systemic circulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Seven factors affecting drug absorption

A
  1. Chemical composition of drug and delivery formulation
  2. Regional differences in blood flow
  3. Transport mechanisms
  4. Permeability characteristics
  5. Ion trapping
  6. Nonspecific binding
  7. Surface area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe aqueous diffusion

A

Small molecules

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

Describe lipid diffusion

A

Driven by concentration gradient, so the rate of absorption increases with increasing drug concentration. However, this may be limited if they are poorly soluble

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

How is lipid solubility affected? How is this predicted?

A

The degree of ionization; through the Henderson-Hasselbalch equation

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

Degree of ionization depends on what?

A

The difference between pH and pKa (0=50-50)

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

Weak bases are more concentrated in __ compartments

A

Acidic

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

Ion trapping

A

Phenomenon when acids/bases get “stuck” in different compartments on the opposite side of neutrality

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

Rate of drug absorption across membranes vs. surface area

A

Directly proportional

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

Where is the main site of absorption and why?

A

Has much higher surface area than the stomach

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

What is the rate limitation with active transport?

A

The process is saturable, and there may be competition for transporters between drugs and other drugs or endogenous substances

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

Most common route of enteral drug administration

A

Oral

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

Forms of oral drugs

A

Solutions, suspensions, capsules, tablets, etc.

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

Describe the first-pass effect

A

Some drugs are highly metabolized when they pass through the liver; only a fraction of the absorbed drug actually reaches systemic circulation

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

Describe enterohepatic circulation and its consequences

A

Drugs may be secreted into the bile and reabsorbed via the intestine, which can delay delivery to circulation and reduce bioavailability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What can affect rates of oral drug absorption?

A

Stomach contents, gastric emptying time

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

What may cause a drug to have less than 100% bioavailability?

A

Incomplete absorption, undergoing metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Describe the salt factor
In rare cases, a drug may have a portion prepared as an inactive salt, so the dose may be adjusted similarly to bioavailability adjustments
26
Advantages of sublingual drug administration
By-passes portal circulation, beneficial for absorption of more basic drugs
27
Disadvantages of sublingual drug administration
Taste and/or discomfort
28
Buccal drug administration
Similar to sublingual
29
Advantages to rectal drug administration
1. 50-60% of absorbed drug by-passes portal circulation and therefore avoids first pass metabolism 2. Useful in cases of nausea and vomiting
30
Disadvantages to rectal drug administration
Discomfort, inconvenience
31
Describe absorption by inhalation.
Passive diffusion, large surface area
32
Common forms of drug inhalation
Volatile gasses and aerosol preparations
33
What is a consideration for drug inhalation?
Absorption varies with depth and duration of inspiration, so it must be controlled by titration or metered inhaler
34
Topical drug administration is usually used for __ therapy.
Local/non-systemic
35
What form of topical drug can reach systemic circulation?
Highly lipid-soluble forms of drugs
36
Common forms of topical drug administration
``` Creams Lotions Gels Ointments Shampoos ```
37
Transdermal drug administration
Reservoir in a patch has a drug that passively diffuses across the skin, which is driven by a concentration gradient
38
What are the benefits of transdermal drug administration?
Controlled release of the drug into the patient, convenient, and bypasses GI tract
39
What are the limitations/risks of transdermal drug administration?
Skin barrier limits the number of drugs that can be delivered by passive diffusion from an adhesive patch, and it could be irritating
40
How is concentration gradient maintained in parenteral drug administration?
Blood flow to the area maintains it
41
Advantages to parenteral drug administration
Greater degree of reliability and precision of administered dose, as well as fewer problems with absorption through the GI system
42
Disadvantages to parenteral administration
``` Sight of needle Pain Tissue damage/irritation Drugs must be in solution Limited volume ```
43
Advantages of subcutaneous administration
Slow, even absorption and rate may be modified by altering blood flow (through temperature)
44
Disadvantages of parenteral administration
Not effective when peripheral circulation is impaired, and there is a limited volume
45
Advantages of intramuscular administration
More rapid absorption than subcutaneous administration, and blood flow can still be altered
46
Disadvantages of IM administration
Potential for infection and nerve damage or inadvertent IV administration
47
Advantages of IV administration
Fastest and most reliable means of achieving a defined blood level
48
Disadvantages of IV administration
Risk of overdose by "bolus effect"
49
Binding of acidic and basic drugs to plasma proteins
Acid drugs: albumin | Basic drugs: alpha-1 acid glycoprotein
50
What happens when proteins are bound to the drug?
They are retained in the plasma
51
One-compartment distribution
A rapid equilibrium is achieved between plasma and tissue distribution following drug administration, and declines mono-exponentially
52
Two-compartment distribution
Rapid distribution to a central compartment (plasma) is followed by a slow distribution to other tissues/binding sites (second compartment). This results in a bi-exponential profile
53
Volume of distribution is used to measure __
How evenly distributed a drug is in the body
54
What is Vd?
A theoretical volume of fluid into which the total drug administered would have to be diluted to produce the concentration in plasma
55
What two things does volume of distribution relate?
Relates dose to the initial plasma concentration of the drug at time = 0
56
How is C0 calculated?
Monoexponential phase of decay is extrapolated backward to t = 0
57
Large Vd is seen in what?
Drugs with a large fat and muscle distribution
58
What happens to the volume of distribution with change in protein binding?
Increase in unbound drug will increase the apparent volume of distribution
59
Plasma is _% of total body weight
5
60
Interstitial fluid is _% of total body weight
16
61
Intracellular fluid is _% of total body weight
35
62
Transcellular fluid is _% of body weight
2
63
Fat is _% of total body weight
20
64
Pattern of distribution for lipid-insoluble drugs
Mainly confined to plasma and interstitial fluids; most do not enter the brain following acute dosing
65
Pattern of distribution for lipid-soluble drugs
Can cross into any compartment, including crossing the the blood-brain barrier; may accumulate in fat
66
What can happen with Vd with lipid-soluble drugs?
May exceed total body volume
67
What class of drug can compete for protein binding?
Sulfonamides, which can increase the unbound fraction of other drugs
68
Drug reservoirs
Fat and muscle. More drug can be stored in these than in systemic circulation; gradual release of drug from these sites can either prolong therapy or result in toxicity

Pharmacology, exam 1 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions