Pharm > Lecture 3 > Flashcards

Lecture 3 Flashcards

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1
Q

What are receptor tyrosine kinases?

A

A type of receptor that plays a role in cell signaling.

Requires 2 signal molecules, attach to bind as a dimer, allowing phosphates to activate sites for effector proteins

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2
Q

What is the function of ionotropic channels?

A

They open when a ligand binds to them, allowing ions to flow through.

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3
Q

How many ligands typically bind to ionotropic channels to open them?

A

Usually requires two of the same ligand.

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4
Q

What is the nicotinic acetylcholine receptor?

A

An example of an ionotropic channel that opens in response to acetylcholine.

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5
Q

What happens when acetylcholine binds to the nicotinic receptor?

A

The channel opens, allowing sodium to flood into the cell.

Once sodium in the cell it opens its neighbors doors allowing action potential

Inactivation gate (inside gate closes) first then activation gate closes (outside gate)

Meanwhile potassium gates are opening to release k out of cell. Repolarizing cell

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6
Q

What is the difference between ionotropic and metabotropic channels?

A

Ionotropic channels are directly linked to ion flow (one whole protein) while metabotropic channels involve GPCR and second messengers (multiple parts to protein)

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7
Q

What does GPCR stand for?

A

G-Protein Coupled Receptor.

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8
Q

What initiates the excitatory post-synaptic potential in olfactory signaling?

A

Binding of an odorant molecule to its GPCR.

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9
Q

What is the role of nitric oxide in blood vessels?

A

It diffuses across membranes and relaxes smooth muscle cells, opening blood vessels.

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10
Q

What is the process of absorption in pharmacokinetics?

A

The process by which a drug permeates across barriers.

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11
Q

List the four main ways that drug permeation can occur.

A
  • Aqueous diffusion
  • Lipid diffusion
  • Special carriers
  • Endocytosis and exocytosis.
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12
Q

What type of drugs typically undergo aqueous diffusion?

A

Hydrophilic drugs.

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13
Q

What are aquaporins?

A

Water channels in the cell membrane that allow water and some small molecules to pass through.

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14
Q

What is the typical structure of a cell membrane?

A

A phospholipid bilayer.

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15
Q

What is a characteristic of lipid-soluble drugs?

A

They can easily cross cell membranes.

Small and uncharged

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16
Q

True or False: Most drugs can freely diffuse across cell membranes.

A

False.

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17
Q

Fill in the blank: The compound _______ is released from blood vessel cells and helps relax smooth muscle.

A

nitric oxide

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18
Q

What is the primary action of steroid hormones in cells?

A

They bind to receptors inside the cytoplasm and activate transcription.

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19
Q

What is the role of cyclic AMP in GPCR signaling?

A

It acts as a second messenger that activates ion channels.

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20
Q

What happens when a drug is bound to albumin in the blood?

A

It cannot diffuse across cell membranes.

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21
Q

What does the term ‘metabotropic channel’ refer to?

A

A channel that opens in response to GPCR activation and second messengers.

Has multiple parts to the protein

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22
Q

What is the main purpose of pharmacokinetics?

A

To understand what the body does to a drug.

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23
Q

What is meant by ‘permeation’ in the context of pharmacokinetics?

A

The process of a drug crossing biological barriers

Aka absorption

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24
Q

What determines whether a charged molecule can cross the cell membrane?

A

Charged molecules cannot freely cross the membrane unless there are channels available.

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25
How do uncharged molecules pass through the cell membrane?
Uncharged molecules can bypass the phosphate head groups and pass through the hydrophobic portion of the membrane.
26
What is the significance of pKa and solution pH in drug absorption?
The pKa of a molecule combined with the solution pH determines if the molecule is charged or uncharged.
27
What are special carriers in drug transport?
Special carriers are molecules that drugs bind to for transport across the membrane.
28
What role do MDR and MRP proteins play in drug transport?
MDR (Multidrug Resistance) and MRP (Multidrug Resistance Associated Protein) transport drugs across membranes, often pumping them back out of cells.
29
True or False: The blood-brain barrier allows most drugs to enter the brain.
False
30
What is the norepinephrine transporter (NET)?
NET is a transporter that takes norepinephrine back into the neuron from the synapse.
31
How do cocaine and tricyclic antidepressants affect norepinephrine levels?
They inhibit the norepinephrine transporter, increasing norepinephrine levels in the synapse.
32
Fill in the blank: SSRIs are selective serotonin _______ inhibitors.
reuptake
33
What is the primary function of the serotonin reuptake transporter (SERT)?
SERT takes serotonin back into the neuron from the synapse.
34
What is the volume of distribution (Vd)?
Vd is a ratio of the amount of drug given to the concentration of the drug in the bloodstream.
35
What does a high volume of distribution imply about a drug?
It implies that the drug leaves the blood and distributes to other tissues.
36
What is endocytosis?
Endocytosis is the process by which a cell engulfs a substance to internalize it.
37
What is exocytosis?
Exocytosis is the process by which a cell expels substances out of the cell.
38
What is the main route of drug elimination from the body?
The main route is through the kidneys, primarily in urine.
39
What is the purpose of pharmacokinetic principles?
To maximize drug effect while minimizing adverse effects.
40
How is drug clearance determined?
By calculating pharmacokinetic variables during clinical trials.
41
What is the role of pharmacodynamics in drug therapy?
To assess the clinical response and effectiveness of the drug.
42
What does the term 'clearance' refer to in pharmacology?
Clearance refers to the volume of plasma from which a substance is completely removed per unit time.
43
What is the significance of dose adjustments in drug therapy?
Dose adjustments are necessary due to variations in drug metabolism and distribution in humans compared to animals.
44
What is the relationship between drug concentration in the blood and its distribution?
The concentration in the blood decreases as the drug distributes to other areas of the body.
45
Fill in the blank: The majority of drug elimination occurs through the _______.
kidneys
46
What is receptor-mediated endocytosis?
It's a process where a cell internalizes substances that bind to specific receptors.
47
What is the result of a drug's high volume of distribution?
The drug is more likely to be found in tissues rather than in the bloodstream.
48
What is the relationship between body water and drug distribution?
Drugs can distribute into various body compartments, including interstitial fluid and plasma, which are part of body water.
49
What does a high volume distribution indicate about a drug?
The drug preferentially distributes to areas outside the blood ## Footnote Examples include extravascular spaces, lipid components, or bone.
50
How is volume distribution calculated?
Volume distribution = amount of drug administered / drug concentration ## Footnote This indicates how a drug is distributed in the body.
51
How do you calculate the dose needed to achieve a target concentration?
Dose = volume distribution * target concentration ## Footnote This formula helps determine the required dosage for effective treatment.
52
What is clearance in pharmacology?
Rate of elimination relative to drug concentration ## Footnote Measured in milliliters per time.
53
How is clearance calculated?
Clearance = rate of elimination / concentration in blood ## Footnote This helps determine how effectively a drug is removed from the body.
54
What is the difference between clearance and rate of elimination?
Clearance is a measure of blood filtering; rate of elimination is the amount of drug removed over time ## Footnote They are linked but represent different concepts.
55
What is first-order elimination?
Clearance is constant; rate of elimination changes with concentration ## Footnote Most drugs follow this elimination pattern.
56
What happens to the concentration of a drug in the blood over time with first-order elimination?
The concentration decreases as more drug is eliminated ## Footnote This reflects the decreasing amount of drug present.
57
How does the concentration of the drug in the blood change over time?
The concentration is constantly dropping over time
58
What is the relationship between rate of elimination and concentration in first-order elimination?
Rate of elimination decreases as concentration decreases
59
What remains constant in first-order elimination?
Clearance remains constant
60
What is the clearance in the example given after one hour when 120 milligrams was removed?
Clearance remains positive; 12% of total concentration was removed
61
What characterizes zero-order elimination?
Rate of elimination is constant; clearance varies
62
What happens to clearance when a drug exhibits zero-order elimination?
Clearance decreases as concentration increases
63
Give an example of a drug that may exhibit zero-order elimination.
Ethanol, phenytoin, salicylates, cisplatin, fluoxetine, omeprazole
64
In which scenario does a drug switch from zero-order to first-order kinetics?
When the concentration is low enough that elimination mechanisms are no longer saturated
65
What determines whether a drug follows zero-order or first-order elimination?
How the drug is being eliminated from the body
66
What is flow-dependent elimination?
Elimination depends on blood flow to the organ and the extraction ratio of the drug
67
What is the classification of drugs based on extraction ratio?
* High extraction (0.7 to 1) * Intermediate extraction (0.3 to 0.7) * Low extraction (less than 0.3)
68
What is half-life?
The time required to decrease the concentration in the blood by one half
69
How is half-life calculated using clearance and volume distribution?
t_half = 0.7 * (volume distribution / clearance)
70
What happens to drug concentration after four half-lives?
It is effectively removed from the body
71
What is the significance of steady-state dosing?
It allows reaching the target concentration within four half-lives
72
How does renal failure affect drug half-life?
It can significantly alter the half-life
73
What is the relationship between blood flow and clearance for high extraction drugs?
High clearance requires both high blood flow and high extraction ratio
74
What happens to a drug after four half-lives?
The drug is essentially going to be down to nothing.
75
What is steady state dosing?
It assures that the concentration needed is reached within four half-lives.
76
What is accumulation in pharmacology?
It occurs when a drug is given before the previous dose has been eliminated.
77
What is the consequence of dosing a drug before four half-lives?
The drug concentration may exceed the target concentration and could become toxic.
78
What is bioavailability?
It refers to how much of a drug reaches the systemic circulation.
79
What is the bioavailability of intravenous drugs?
100%.
80
What is the first pass effect?
It's when a drug is metabolized in the liver before reaching systemic circulation.
81
What factors affect bioavailability?
* Hydrophilicity or hydrophobicity of the drug * pKa of the drug * Solubility of the drug * Formulation and route of administration * Health of the GI tract * Drug interactions * Circadian rhythms
82
True or False: High absorption in the gut indicates high bioavailability.
False.
83
What is the purpose of a loading dose?
To quickly reach the target concentration.
84
What is the loading dose calculation formula?
Loading dose = Volume of distribution × Target concentration.
85
What is the relationship between clearance and dosing rate at steady state?
Dosing rate = Clearance × Target concentration.
86
Fill in the blank: If a drug is administered orally, its bioavailability is often ______.
less than 100%.
87
What happens to the dosing rate if the dosing interval is shorter?
The required dose will decrease.
88
What is the significance of individual patient variables in drug dosing?
They can affect the drug's pharmacokinetics and necessary adjustments may be required.
89
What is the target concentration for digoxin in heart failure management?
1 nanogram per milliliter.
90
What is the effect of administering a drug with a short interval?
It may lead to accumulation and increased drug concentration.
91
What is the importance of the hepatic portal system?
It allows the liver to metabolize drugs before they reach systemic circulation.
92
What is the dosing rate for a patient weighing 102 kg if the calculated dosing rate is 5.2 mg/hour?
5.2 mg/hour.
93
What happens to drug concentrations at longer dosing intervals?
They may lead to toxicity or insufficient therapeutic effect.
94
What is the effect of administering a drug via sublingual route?
It bypasses the first-pass effect.
95
What is a common characteristic of drugs with low bioavailability?
They may be poorly absorbed or extensively metabolized by the liver.
96
True or False: Morphine has a high bioavailability when administered orally.
False.
97
What is the expected effect of a drug in an emergency situation?
Immediate effect.
98
What is meant by 'steady-state dosing'?
It refers to maintaining a constant drug concentration in the body.
99
What is the consequence of a drug having a high extraction ratio in the liver?
It can lead to low bioavailability.
100
What is the impact of a patient's health status on drug dosing?
It can alter the drug's pharmacokinetics and required dosing adjustments.
101
What does the loading dose take into account?
The volume distribution rather than the clearance. ## Footnote Loading dose is crucial for achieving therapeutic levels quickly.
102
How is the loading dose calculated?
Loading dose = volume of distribution × carrier concentration. ## Footnote This calculation is essential for determining the appropriate initial dose.
103
What is the recommended method for administering a loading dose?
Administer slowly over a period of time, such as one to five minutes. ## Footnote Slow administration allows for proper dispersion into other areas.
104
Why should a loading dose be given slowly?
To allow dispersion into other areas and maintain target concentration. ## Footnote A high volume distribution means the drug will move outside the blood.
105
What is the primary goal of a loading dose?
To reach the target concentration very quickly. ## Footnote This helps avoid delays associated with half-life waiting periods.
106
True or False: A loading dose is intended to be given rapidly in a few seconds.
False. ## Footnote It should be administered slowly to ensure effective dispersion.
107
Fill in the blank: The loading dose is designed to achieve the target concentration __________.
[very quickly]. ## Footnote This contrasts with waiting for the drug to reach this level through normal dosing intervals.
Pharm
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