Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Neuropsychopharmacology > Lecture 7: Pharmacokinetics Part II > Flashcards

Lecture 7: Pharmacokinetics Part II Flashcards

(85 cards)

Start Studying
1
Q

what are the two phases of metabolism

A

phase 1 & phase 2

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

what is metabolism

A

the chemical reactions that change a drug into a compound more easily excreted or eliminated by the body

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

what enzymes are important for metabolism

A

CYP450

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

where does most metabolism happen

A

in the liver

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

what are the options for the product of phase I metabolism

A

drug metabolite w/ modified activity or inactive drug metabolite

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

what happens to highly lipophilic drugs

A

accumulation (storage in body tissues)

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

what happens after highly lipophilic drugs accumulate in body tissues

A

phase 1 metabolism (bioactivation or inactivation)

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

what is the produce of phase 1 metabolism

A

polar drug

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

what happens to polar drugs after undergoing phase 1 metabolism

A

phase 2 metabolism (inactivation)

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

what is the product of phase 2 metabolism

A

hydrophilic drug

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

what happens to hydrophilic products of phase 2 metabolism

A

excretion (renal or biliary)

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

what happens to lipophilic drugs

A

undergo phase 1 metabolism

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

what happens to polar drugs

A

undergo phase 2 metabolism

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

what happens to hydrophilic drugs

A

excreted

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

what chemical change happens to drugs during phase 1 metabolism

A

body exposes polar groups on drug

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

what reactions does phase 1 consist of

A

oxidation, reduction, or hydrolysis reactions

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

purpose of phase 1 reactions

A

convert lipophilic drugs to more polar molecules by exposing polar functional groups (like -OH or -NH2)

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

what enzymes do phase 1 reactions use

A

cytochrome P450 enzymes (CYP450)

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

which phase(s) do polar drugs go through

A

bypass phase 1 & go to phase 2 reactions

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

what is the superfamily of enzymes crucial for phase 1 metabolism

A

cytochrome P450 enzymes

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

what is the result of different phenotypic changes between CYP450 enzymes

A

people respond differently to the same drugs

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

which enzymes have the highest amount of allelic variants

A

CYP2D6, CYP2B6, and CYP2A6

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

what are the four types of phenotypical changes in CYPs

A

poor metabolizers (PM), intermediate metabolizers (IM), extensive metabolizers (EM), & ultra-rapid metabolizers (UM)

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

result of poor metabolizer variation

A

higher risk of side effects due to decreased medication clearance (higher blood levels)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
result of intermediate metabolizer
desired efficacy; normal rate of medication clearance
26
result of extensive metabolizer (normal metabolizer) variation
desired efficacy; normal rate of medication clearance
27
result of rapid & ultra rapid metabolizers variations
risk of inefficacy due to increased medication clearance (lower blood levels)
28
what types of drugs interact w/ grapefruit?
- administered orally - low-to-intermediate bioavailability - metabolized by the CYP3A4 enzyme
29
why is grapefruit a risk factor
irreversibly inhibits CYP3A4 in the GI tract; drug wouldn't break down, so you would get really high dose & adverse side effects
30
what do conjugation reactions do in phase 2
add bulky group to exposed functional group from phase 1
31
what are the most common types of conjugation reactions?
glucuronidation, methylation, acetylation
32
what is the goal of phase 2 reactions
to funnel metabolites to excretion
33
excretion
removing drugs & their metabolites from the body
34
primary modes of excretion
- GI system (feces) - urinary system (urine) - respiratory system (exhaled air)
35
clearance
the efficiency of irreversible elimination of a drug from systemic circulation (L/Hr)
36
how can a drug be cleared & eliminated?
by being excreted (removed from the body in an unchanged form) or undergoing biotransformation (changed into something chemically similar)
37
what is systemic clearance
the sum of all clearances
38
what is renal clearance
the fraction of total clearance which is handled by the kidneys
39
what is metabolic clearance
the fraction of total clearance which is the consequence of drug biotransformation/metabolism
40
what is hepatic clearance
the fraction of total clearance which is handled by the liver, regardless of whether this is by biliary excretion or by metabolism
41
formula for elimination rate
(clearance in L/Hr) * (plasma drug concentration in mg/L) Cl * C
42
formula for clearance
(elimination rate in mg/hr) / (concentration in mg/L)
43
what is the functional unit of the kidney
nephron - each kidney has ~ 1 million nephrons
44
what are the nephron's functional units
glomerulus, proximal tubule, & distal tubule
45
when can a drug enter the glomerulus
when unbound by plasma proteins (they are too big to undergo glomerular filtration)
46
where does a drug go once entering the glomerulus
proximal tubule
47
what does the proximal tubule do
allows active transport from the bloodstream to the tubule
48
where does the drug go after proximal tubule
distal tubule
49
where does the drug go after distal tubule
some can be reabsorbed by the blood if it's small enough to be passively diffused, but most is excreted in the kidneys
50
where does filtration happen
in the glomerulus
51
why is it a problem if albumin or red blood cells are found in the urine
they are too big to pass typically
52
what does too much creatine in the blood signal
kidney problem
53
how does protein binding affect glomerular filrtation
highly protein bound drugs are poorly filtered in the glomerulus
54
how does drug size affect glomerular filtration
molecules less than 30 Angstroms are freely filtered at the glomerulus
55
secretion
transport of drugs out of the blood & into the urine - occurs in the proximal tubule by active transport
56
what are the active transporter systems
- weak acid transporters - weak base transporters - nucleoside transporters - p-glycoprotein transporters
57
why are most active transport pumps for secretion symporters
they use concentration gradient of sodium & intracellular negative AP to drive the substrate out of blood & into the tubule
58
where does reabsorption occur
distal tubule
59
what is passive reabsorption
if a drug becomes so concentrated in the tubule it sets up a gradient which favors the diffusion of drug back into the tubular cells & back out into the blood
60
active reabsorption
kidneys reabsorb water-soluble vitamins, ions, amino acids, etc; if a drug looks like these substances it will be reabsorbed
61
half life
the time required to reduce the concentration of a drug in half
62
how does an increase in Vd affect half life
increases it
63
how does a decrease in the rate of clearance affect half life
increases it
64
what happens to secretion of a drug if it is more distributed
it won't be secreted as easily since it is hanging out in the tissues
65
what happens to half life if a drug is rapidly cleared
it is being eliminated rapidly
66
elimination rate constant formula
k = (clearance / volume of distribution) k = Cl/Vd
67
half life formula
t1/2 = (log(2) * Vd)/Cl = (0.693 * volume of distribution)/clearance
68
1st order elimination kinetics
depends on drug concentration
69
0 order elimination kinetics
independent of concentration; constant
70
why is half-life meaningless in 0 order kinetics
bc concentration is halved at inconsistent time intervals
71
how does doubling a dose affect half life
increases duration of action by one half-life
72
how does chronic dosing affect half life
approaches steady state after 5 half lives
73
toxicity of drugs w/ longer half lives
more toxic due to their slower clearance from the body
74
what is dangerous about incorrect dosing
can lead to toxicity, as the plasma drug concentrations may exceed the desired therapeutic range
75
how does hepatitic or renal disease affect half life
metabolism & clearance may be impaired
76
toxicokinetics
what the body does to the drug
77
toxicodynamics
what the drug does to the body
78
what is the purpose of toxicology
to investigate potential harmful effects of a substance on living systems
79
what makes a drug "toxic"?
the dose
80
what is the therapeutic index
the ratio of the TD50 to the ED50, a parameter which reflects the selectivity of a drug to elicit a desired effect rather than toxicity
81
what is TD50
the mean toxic dose; the dose required to produce a defined toxic effect in 50% of subjects
82
what is ED50
the median effective dose, the dose at which 50% of individuals exhibit the specified quantal effect
83
what is the median lethal dose
the dose required to kill 50% of subjects
84
what does a larger therapeutic index mean
greater the relative safety of a drug
85

Neuropsychopharmacology (8 decks)

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