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Lecture4 Flashcards

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1
Q

What is an endosome?

A

A membrane-bound structure inside the cell formed when the cell engulfs something through endocytosis.

Endosomes transport substances within the cell and can merge with the cell membrane during exocytosis.

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2
Q

What is the difference between endocytosis and exocytosis?

A

Endocytosis brings substances into the cell, while exocytosis takes substances out of the cell.

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3
Q

What is desensitization in relation to GPCRs?

A

The process where beta-arrestin binds to GPCRs and translocates them to a clathrin-coated pit, leading to endocytosis.

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4
Q

Define clearance in pharmacology.

A

The volume of blood from which a drug is completely removed per unit time.

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5
Q

What is the relationship between clearance and zero-order kinetics?

A

In zero-order kinetics, the rate of elimination is constant, leading to variable clearance across different volumes of blood.

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6
Q

What is a loading dose?

A

An initial higher dose of a drug given to rapidly achieve the target concentration.

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7
Q

What is steady state dosing?

A

A dosing strategy to maintain a constant drug level in the body as the drug is eliminated.

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8
Q

What is therapeutic drug monitoring?

A

A method used to measure drug concentrations in the blood to optimize dosing based on individual patient metabolism.

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9
Q

What is the purpose of a creatinine clearance test?

A

To assess kidney function by measuring the rate at which creatinine is cleared from the blood.

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10
Q

What is drug biotransformation?

A

The metabolic process that converts drugs into different forms, which may be more or less active.

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11
Q

What are pro-drugs?

A

Drugs that are administered in an inactive form and are converted into an active form through biotransformation.

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12
Q

Give an example of a pro-drug.

A

Codeine, which is converted into morphine to exert its effects.

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13
Q

What is the significance of genetic variance in drug metabolism?

A

Genetic differences can lead to variations in drug effectiveness and metabolism rates among individuals.

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14
Q

What does it mean if a drug is said to have a variable clearance rate?

A

It means that the rate at which the drug is eliminated from the body can differ among individuals or conditions.

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15
Q

Fill in the blank: The kidneys filter blood, but if the rate of elimination is constant, the clearance will be _______.

A

variable.

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16
Q

True or False: The amount of blood flow to the kidneys changes with different doses of a drug.

A

False.

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17
Q

What is the ideal body weight calculation used for?

A

To determine drug dosing for individuals where the drug does not penetrate fat, ensuring accurate dosing.

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18
Q

What factors are considered in therapeutic drug monitoring?

A
  • Normal kidney and liver function
  • Serum creatinine levels
  • Drug binding to albumin.
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19
Q

What happens to morphine during biotransformation?

A

It can be converted into active metabolites like morphine-6-glucuronide or inactive forms like normorphine.

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20
Q

What does clearance depend on in pharmacology?

A

Factors such as kidney function, liver function, blood flow, and drug binding characteristics.

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21
Q

What is the common weight used in pharmacology textbooks for drug dosing calculations?

A

70 kilograms.

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22
Q

What is a prodrug?

A

A prodrug is a medication that is administered in an inactive form and requires metabolic activation to become effective.

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23
Q

What is the role of enzymes in the activation of codeine?

A

Enzymes convert codeine into its active metabolite, morphine, and a deficiency in this enzyme can result in non-efficacy of codeine.

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24
Q

What is biotransformation?

A

Biotransformation is the process by which the body chemically alters drugs or other substances.

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25
Where does biotransformation primarily occur in the body?
Biotransformation primarily occurs in the liver.
26
What is the hepatic portal system?
The hepatic portal system is a network that carries blood from the gastrointestinal tract to the liver. … Capillary bed to vessel to capillary bed
27
What is the first-pass effect?
The first-pass effect refers to the metabolism of an oral drug by the liver before it reaches systemic circulation.
28
What are hepatocytes?
Hepatocytes are the main functional cells of the liver involved in drug metabolism.
29
What are the two main forms of reactions in drug biotransformation?
Phase one and phase two reactions.
30
What is the purpose of phase one reactions?
Phase one reactions involve oxidation, reduction, or hydrolysis to make drugs more polar and hydrophilic.
31
What occurs during phase two reactions?
Phase two reactions involve the conjugation of the drug with another substance, increasing its molecular weight.
32
Fill in the blank: Phase one reactions typically involve _______.
oxidation, reduction, hydrolysis
33
What is the significance of cytochrome P450 enzymes?
Cytochrome P450 enzymes are crucial for the oxidation of drugs during phase one biotransformation. Making drugs more hydrophilic which allows for excretion
34
What is the result of a drug being oxidized by cytochrome P450?
The drug becomes more hydrophilic due to the addition of functional groups like hydroxyl groups.
35
What does the term substrate specificity mean in the context of cytochrome P450?
Substrate specificity refers to the ability of an enzyme to act on multiple drugs rather than just one.
36
What does CYP stand for in cytochrome P450 nomenclature?
CYP stands for cytochrome P450.
37
What does the asterisk (*) signify in CYP nomenclature?
The asterisk denotes the wild type version of the enzyme.
38
True or False: Phase two reactions occur in any cell in the body.
True
39
What is the primary organ for drug absorption following oral administration?
The small intestine.
40
What happens to drugs absorbed in the gastrointestinal tract?
They enter the hepatic portal vein and are transported to the liver.
41
What is the difference between the hepatic vein and the portal vein?
The hepatic vein carries blood away from the liver, while the portal vein carries blood from the intestines to the liver.
42
What type of drugs are more likely to be excreted in the urine?
Hydrophilic drugs.
43
Name one common reaction type that occurs during phase one biotransformation.
Oxidation.
44
What is the fate of drugs after they are biotransformed in hepatocytes?
They may be excreted into bile or back into the bloodstream.
45
What can happen to liver cells in low-oxygen environments?
Liver cells can die off, particularly those closer to the hepatic vein.
46
What does CYP1A2 metabolize?
CYP1A2 may metabolize drugs like acetaminophen ## Footnote CYP1A2 is a cytochrome P450 enzyme involved in drug metabolism.
47
What is the significance of the star one version of a gene?
Star one is always the wild type of the gene ## Footnote Variants like star two or star three indicate mutations.
48
How many different human P450s are there?
There are over 50 different human P450s ## Footnote A small percentage of these are involved in drug metabolism.
49
Where are cytochrome P450 enzymes primarily found?
In microzones within the liver, specifically the sarcoplasmic reticulum ## Footnote These microzones are specialized membrane structures.
50
What does induction of cytochrome P450 enzymes mean?
Induction means an increase in the amount of those enzymes ## Footnote This can result from the action of other drugs.
51
What is the effect of inhibition on cytochrome P450 enzymes?
Inhibition decreases the amount of those enzymes ## Footnote This can lead to decreased metabolism of drugs that rely on those enzymes.
52
Fill in the blank: IF CYP3A4 inactivates Drug one, and drug one is metabolized by CYP3A4 drug one becomes ______.
inactive ## Footnote This process is influenced by other drugs that may induce or inhibit CYP3A4.
53
What happens when a drug that induces CYP3A4 is taken with another drug?
The second drug will be metabolized at a higher rate ## Footnote This can lead to increased effects or potential overdoses.
54
What is the role of grapefruit juice concerning CYP3A4?
Grapefruit juice is an inhibitor of CYP3A4 ## Footnote It can lead to increased levels of drugs metabolized by this enzyme.
55
What is the effect of cruciferous vegetables on CYP1A2?
Cruciferous vegetables are inducers of CYP1A2 ## Footnote This can reduce the effectiveness of drugs like warfarin.
56
How does eating lots of Brussels sprouts affect warfarin levels?
It leads to less active warfarin ## Footnote Increased CYP1A2 activity results in faster conversion of warfarin.
57
What type of reaction is glucuronidation?
Phase 2 It is a conjugation reaction that attaches glucose to drugs ## Footnote UDP glucuronic acid is the endogenous reactant involved.
58
What is the effect of taking a drug that inhibits CYP3A4?
There will be less inactivation of active drugs ## Footnote This can lead to higher concentrations of the active drug.
59
What must clinicians consider when prescribing medications?
Potential drug-drug interactions due to cytochrome P450 enzymes ## Footnote Warnings about drug interactions are often included in drug labels.
60
True or False: CYP3A4 is responsible for metabolizing 50% of all drugs.
True ## Footnote It is one of the most important cytochrome P450 enzymes.
61
What percentage of drugs are metabolized by CYP2D6?
20% ## Footnote CYP2D6 is another significant enzyme in drug metabolism.
62
What is a prodrug?
A drug that is activated into its active form by enzymes ## Footnote An example is codeine, which is converted to morphine.
63
What is an example of a substance that can inhibit CYP2B6?
Clopidogrel ## Footnote It can affect the metabolism of drugs that are substrates for CYP2B6.
64
What happens when two drugs target the same cytochrome P450 enzyme?
They may interact and affect each other's metabolism ## Footnote This is critical in managing polypharmacy.
65
What is glucuronidation?
Phase 2 reaction A conjugation reaction that attaches a glucose molecule to a drug, increasing its water solubility ## Footnote The endogenous reactant is UDP glucuronic acid, which acts as a carrier molecule.
66
What is the role of UDP in glucuronidation?
UDP carries the glucose component to the drug and binds it ## Footnote UDP stands for uridine diphosphate.
67
What are phase two reactions?
Reactions that modify drugs by attaching larger molecules, making them more water soluble ## Footnote Examples include glucuronidation and glutathione conjugation.
68
What is the significance of UGT enzymes?
They are responsible for transferring glucuronic acid to drugs during glucuronidation ## Footnote There are 15 different UGT enzymes, falling into two main families.
69
True or False: Drugs can undergo both phase one and phase two reactions simultaneously.
True ## Footnote Different components of the same drug may undergo different reactions.
70
What happens if an inhibitor of UGT enzymes is present?
There will be less glucuronide form and more of the parent drug form ## Footnote This can affect the drug's activity, potentially leading to toxicity.
71
What is codeine metabolized into?
Morphine ## Footnote Codeine is considered a prodrug, while morphine is the active drug.
72
What is glutathione's role in drug metabolism?
It detoxifies xenobiotics by increasing their water solubility ## Footnote Glutathione-S-transferase is the enzyme that transfers glutathione to compounds.
73
Fill in the blank: Glutathione detoxification is associated with _______.
detoxification ## Footnote It helps remove various toxins and harmful chemicals from the body.
74
What can lead to the formation of toxic metabolites during drug metabolism?
Overdosing on drugs ## Footnote This can overwhelm normal detox pathways, resulting in toxic byproducts.
75
What are the two phase two reactions acetaminophen undergoes at normal doses?
* Glucuronidation * Sulfation ## Footnote Both reactions convert acetaminophen into non-toxic metabolites.
76
What is the role of the enzyme C2E1 in acetaminophen overdose?
It activates a phase one reaction that produces a toxic intermediate ## Footnote This toxic intermediate can bind to liver cells and cause damage.
77
What happens when glutathione is depleted during acetaminophen overdose?
The reactive toxic intermediate binds to cell proteins, leading to liver cell death ## Footnote This process can occur within minutes to hours.
78
What is the primary target organ affected by acetaminophen toxicity?
Liver ## Footnote Liver damage is a critical concern during acetaminophen overdose.
79
What is the significance of plasma cholinesterase?
It breaks down acetylcholine in the body ## Footnote This includes both endogenous acetylcholine and any administered cholines.
80
What factors can affect drug metabolism?
* Diet * Age * Sex * Disease states ## Footnote These factors can influence how drugs are metabolized and their effectiveness.
81
What is pharmacogenomics?
The study of how genetics affect drug metabolism and responses ## Footnote It helps in personalizing medicine based on an individual's genetic makeup.
82
True or False: Genetic tests can help predict how a patient will respond to a drug.
True ## Footnote Genetic testing can identify poor or ultra-rapid metabolizers, aiding in drug selection.
83
What does personalized medicine aim to achieve?
The right drug, right dose, right patient at the right time ## Footnote It focuses on tailoring treatment based on individual genetic profiles.
84
What is the potential outcome of using genetic testing in drug dosing?
It can predict and explain abnormal reactions to medications ## Footnote Personalized dosing can improve efficacy and reduce adverse effects.
85
What percentage of patients typically respond well to SSRI medications?
Approximately 62% ## Footnote This indicates a significant variation in drug response among individuals.
86
What is the challenge of drug therapy in conditions like depression and cancer?
Many patients do not respond well to the first drug prescribed ## Footnote This necessitates multiple trials to find effective treatments.
87
What is the overall goal of personalized medicine?
The right drug, the right dose, the right indication, the right patient at the right time.
88
How many bases are in the human genome?
3.2 billion bases.
89
What are the four types of bases found in DNA?
* Adenines * Guanines * Cytosines * Thymines
90
Approximately how many genes do humans have?
About 30,000 genes.
91
What percentage of the human genome is identical across individuals?
99.9%.
92
What are SNPs?
Single nucleotide polymorphisms.
93
What are alleles?
Different forms of a gene that result in variations in the amino acid sequence.
94
What is the wild type?
The most common version of a gene.
95
What is a synonymous SNP?
A change that does not alter the amino acid produced.
96
What is a non-synonymous SNP?
A change that alters the amino acid sequence of a protein.
97
What disease is caused by a single nucleotide polymorphism?
Sickle cell anemia.
98
What is the effect of CYP2C9 star 1?
It is the wild type variant with normal enzyme activity.
99
What is a poor metabolizer?
An individual with two mutated copies of a gene that affect drug metabolism.
100
What is the effect of mutations in CYP2C19?
They can lead to complete inactivity of the enzyme.
101
What is a rapid metabolizer?
An individual with extra copies of a gene that increase drug metabolism.
102
What is the role of CYP2D6?
It metabolizes various drugs including codeine.
103
What happens if an individual lacks functional CYP2D6?
They may experience reduced efficacy of codeine.
104
What is Herceptin used for?
It is used for treating HER2 positive cancers.
105
What must be tested before administering Herceptin?
The tumor must be tested for HER2 positivity.
106
What are purine analogs used for?
They inhibit the growth of cancer cells.
107
What is the role of TPMT in drug metabolism?
It converts 6-mercaptopurine to 6-methylmercaptopurine.
108
What can happen to patients with low TPMT activity?
They may experience toxic side effects from standard drug doses.
109
What are the three TPMT alleles that cause deficiency?
* Star 2 * Star 3A * Star 3C
110
What is the impact of having two mutant alleles of TPMT?
Increased oxidized metabolites and potential for severe side effects.
111
Fill in the blank: The _______ variant of CYP2D6 may lead to hyperactivity in drug metabolism.
star 8
112
True or False: Genetic testing can help determine the appropriate drug dosage for individuals.
True
113
What does TPMT stand for?
Thiopurine S-methyltransferase ## Footnote TPMT is an enzyme that affects the metabolism of thiopurine drugs.
114
How does TPMT activity relate to drug dosing?
If TPMT activity goes down, oxidized metabolites go up, causing side effects ## Footnote Individualized dosing is necessary based on TPMT activity.
115
What are the two drugs highly affected by TPMT polymorphisms?
* Azathioprine * Mercaptopurine ## Footnote These drugs are thiopurines that require careful dosing based on TPMT activity.
116
What is Warfarin primarily used for?
It is an anticoagulant used for patients who develop clots ## Footnote Warfarin was initially discovered as a rat poison.
117
Who discovered Warfarin and under what circumstances?
The University of Wisconsin discovered it while investigating bleeding disorders in cows ## Footnote They found that a mold on clover produced Warfarin.
118
What is the relationship between Warfarin and bleeding events?
Warfarin is associated with major bleeding events in 2 to 16% of patients ## Footnote Minor bleeding events are likely higher than 30%.
119
What are the two forms of Warfarin?
* R form * S form ## Footnote These forms have different potencies and are metabolized by different enzymes.
120
Which enzyme primarily metabolizes Warfarin?
CYP2C9 ## Footnote Genetic variations in CYP2C9 can affect Warfarin metabolism.
121
What percentage of the population requires dose adjustments for Warfarin?
84% ## Footnote Only about 16% do not need dose adjustments.
122
What is the recommendation regarding genetic testing for patients on Warfarin?
Genetic testing is recommended but not required ## Footnote The FDA is still reviewing the necessity of this testing.
123
What are the two genetic variants that affect Warfarin therapy?
* CYP2C9 * VKORC1 ## Footnote These variants can lead to reduced metabolism of Warfarin.
124
What is the significance of the star 1 and star 3 versions of CYP2C9?
Star 1 indicates wild-type metabolism, while star 3 indicates reduced metabolism ## Footnote This affects how patients respond to Warfarin.
125
What is the consequence of higher Warfarin concentrations in patients with variant alleles?
Increased risk of adverse bleeding events ## Footnote Patients with variants may have more Warfarin present at normal doses.
126
What will be covered in the next lecture?
Drug transporters and a review for exam one ## Footnote Students can ask questions during the review.
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