Pharmacology Flashcards
1
Q
What are receptors in pharmacodynamics?
A
Specialized proteins that bind to endogenous ligands or drugs to initiate a physiological response.
2
Q
Give an example of a receptor and its function.
A
Beta-adrenergic receptors mediate the effects of epinephrine and norepinephrine.
3
Q
What are ion channels?
A
Pore-forming proteins in cell membranes that regulate ion flow based on electrochemical gradients.
4
Q
Provide an example of an ion channel blocker.
A
Nifedipine, a calcium channel blocker, inhibits calcium influx to cause vasodilation.
5
Q
What is the role of enzymes in pharmacodynamics?
A
Biological catalysts that facilitate biochemical reactions, acting as inhibitors or activators.
6
Q
Give an example of an enzyme inhibitor.
A
Neostigmine, which inhibits acetylcholinesterase, prolonging acetylcholine activity.
7
Q
What are transporters (carrier proteins)?
A
Membrane proteins that facilitate the movement of substances across cell membranes.
8
Q
Provide an example of a transporter and its function.
A
The serotonin transporter (SERT) reuptakes serotonin from the synaptic cleft.
9
Q
What are ligand-gated ion channels?
A
Receptors directly coupled to ion channels that open upon ligand binding.
10
Q
Give an example of a ligand-gated ion channel.
A
Nicotinic acetylcholine receptor (nAChR) allows sodium entry upon acetylcholine binding.
11
Q
What are G-protein coupled receptors?
A
Receptors that activate intracellular signaling cascades via G-proteins upon ligand binding.
12
Q
Provide an example of a G-protein coupled receptor.
A
Beta-adrenergic receptors activate adenylate cyclase, increasing cAMP levels.
13
Q
What are kinase-linked receptors?
A
Receptors that mediate effects through phosphorylation cascades leading to gene transcription.
14
Q
Provide an example of a kinase-linked receptor.
A
Insulin receptor, which triggers glucose uptake via GLUT4 translocation.
15
Q
What are nuclear receptors?
A
Intracellular receptors functioning as transcription factors when activated.
16
Q
Give an example of a nuclear receptor.
A
Glucocorticoid receptor binds cortisol and modulates gene expression.
17
Q
What are the types of gating for ion channels?
A
Voltage-gated, ligand-gated, and mechanically gated.
18
Q
What is selectivity in drug action?
A
A drug’s ability to preferentially bind to a specific target.
19
Q
Define drug potency.
A
The drug concentration required to elicit 50% of its maximal effect (EC₅₀).
20
Q
What does drug efficacy refer to?
A
The maximum effect a drug can produce, regardless of dose.
21
Q
What are full agonists?
A
Drugs that produce maximal receptor activation.
22
Q
What is a partial agonist?
A
A drug that produces a submaximal response even at high concentrations.
23
Q
What is an inverse agonist?
A
A drug that produces the opposite effect of an agonist.
24
Q
Differentiate between reversible and irreversible competitive antagonists.
A
Reversible antagonists can be displaced by increasing agonist concentration; irreversible antagonists bind covalently.
25
What is orthosteric modulation?
Binding at the receptor's active site.
26
What is allosteric modulation?
Binding at a separate site, modifying receptor activity.
27
What factors affect drug absorption?
Lipid solubility, pH & ionization, first-pass metabolism.
28
What is the definition of drug bioavailability?
The fraction of the administered dose reaching systemic circulation unchanged.
29
What is the central compartment in the two-compartment model?
Rapidly perfused organs such as heart, liver, and kidney.
30
What occurs during first-pass metabolism?
Hepatic metabolism before reaching systemic circulation, reducing oral drug bioavailability.
31
What are the two phases of biotransformation?
Phase 1: Oxidation, reduction, hydrolysis; Phase 2: Conjugation.
32
What is renal clearance?
The volume of plasma cleared of a drug per unit time.
33
Define plasma half-life.
The time required for the plasma concentration of a drug to decrease by 50%.
34
What is the difference between first-order and zero-order kinetics?
First-order: Constant fraction eliminated per unit time; Zero-order: Constant amount eliminated per unit time.
35
What neurotransmitter is primarily used in the sympathetic nervous system?
Norepinephrine (NE).
36
What are the key effects of the parasympathetic nervous system?
Decreased heart rate, increased digestion, pupil constriction, bronchoconstriction.
37
What are cholinergic receptors?
Receptors that bind acetylcholine.
38
Give an example of a beta-1 adrenergic receptor effect.
Increases heart rate and contractility.
39
What is the role of acetylcholinesterase inhibitors?
They increase acetylcholine levels.
40
What is the function of dopamine in the autonomic nervous system?
Modulates blood pressure and renal function.
41
True or False: Serotonin affects mood and gut motility.
True.
42
What are receptors?
Specialized proteins that bind to endogenous ligands or drugs to initiate a physiological response
## Footnote
Key role in signal transduction.
43
What type of receptors are beta-adrenergic receptors?
G-protein coupled receptors (GPCRs)
## Footnote
Mediate effects of epinephrine and norepinephrine.
44
What is the function of drugs like propranolol?
Inhibit beta-adrenergic receptors to reduce heart rate and blood pressure
## Footnote
Propranolol is a beta-blocker.
45
What are ion channels?
Pore-forming proteins in cell membranes that regulate ion flow based on electrochemical gradients
## Footnote
Drugs can block or modulate ion channels.
46
What is the role of calcium channels?
Allow calcium influx into cells
## Footnote
Important for various physiological processes.
47
What does nifedipine do?
Inhibits calcium channels to cause vasodilation, reducing blood pressure
## Footnote
Nifedipine is a calcium channel blocker.
48
What are enzymes?
Biological catalysts that facilitate biochemical reactions
## Footnote
Drugs can act as inhibitors or activators.
49
What is the function of acetylcholinesterase (AChE)?
Breaks down acetylcholine
## Footnote
Key in neurotransmission.
50
What does neostigmine do?
Inhibits AChE, prolonging acetylcholine activity
## Footnote
Improves muscle contraction in myasthenia gravis.
51
What are transporters (carrier proteins)?
Membrane proteins that facilitate the movement of substances across cell membranes
## Footnote
Includes ions, nutrients, and neurotransmitters.
52
What is the function of the serotonin transporter (SERT)?
Responsible for reuptake of serotonin from the synaptic cleft
## Footnote
Critical in regulating mood.
53
What does fluoxetine do?
Blocks SERT, increasing serotonin levels
## Footnote
Improves mood in depression; it is an SSRI.
54
What are Ligand-Gated Ion Channels?
Receptors that are directly coupled to ion channels and open upon ligand binding, allowing ions to pass through.
## Footnote
Example: The nicotinic acetylcholine receptor (nAChR) at neuromuscular junctions allows sodium (Na⁺) entry upon acetylcholine binding, triggering muscle contraction.
55
What is the function of G-Protein Coupled Receptors?
They activate intracellular signaling cascades via G-proteins upon ligand binding, influencing cell function indirectly through second messengers.
## Footnote
Example: Beta-adrenergic receptors (Gs-protein coupled) activate adenylate cyclase, increasing cAMP levels, leading to increased cardiac contractility.
56
What do Kinase-Linked Receptors mediate?
They mediate effects through phosphorylation cascades, leading to gene transcription and protein synthesis.
## Footnote
Example: The insulin receptor is a tyrosine kinase receptor that triggers glucose uptake via GLUT4 translocation in muscle and fat cells.
57
How do Nuclear Receptors function?
They are intracellular receptors that function as transcription factors when activated.
## Footnote
Example: The glucocorticoid receptor binds cortisol, moves to the nucleus, and modulates gene expression, reducing inflammation.
58
What are the types of gating mechanisms for ion channels?
They include:
* Voltage-gated
* Ligand-gated
* Mechanically gated
59
What triggers Voltage-gated ion channels to open or close?
Changes in membrane potential.
## Footnote
Example: Voltage-gated Na⁺ channels in neurons.
60
What causes Ligand-gated ion channels to open?
The binding of a specific molecule.
## Footnote
Example: GABA-A receptor allowing Cl⁻ influx.
61
What do Mechanically gated ion channels respond to?
Physical forces like stretch.
## Footnote
Example: Mechanoreceptors in touch-sensitive neurons.
62
What is one modulation mechanism for ion channels?
Phosphorylation, which can enhance or inhibit channel activity.
63
How can ligand binding affect ion channels?
Agonists or antagonists can modulate ion flow.
64
What is the effect of voltage changes on ion channels?
Ion channels respond to depolarization or hyperpolarization.
65
What determines the selectivity of ion passage through channels?
Pore size, charge distribution, and amino acid composition.
66
What is selectivity in pharmacodynamics?
A drug’s ability to preferentially bind to a specific target
## Footnote
Example: atenolol selectively blocks beta-1 receptors, sparing beta-2 receptors.
67
How is affinity measured?
By the dissociation constant (Kd)
## Footnote
Indicates the strength of drug binding to its receptor.
68
What does potency refer to in pharmacodynamics?
The drug concentration required to elicit 50% of its maximal effect (EC₅₀)
## Footnote
A measure of the drug's effectiveness at a given dose.
69
Define efficacy in the context of pharmacodynamics.
The maximum effect a drug can produce, regardless of dose.
70
What is a full agonist?
Produces maximal receptor activation
## Footnote
Example: morphine at opioid receptors.
71
Describe a partial agonist.
Produces a submaximal response even at high concentrations
## Footnote
Example: buprenorphine.
72
What is an inverse agonist?
Produces the opposite effect of an agonist by stabilizing the inactive receptor conformation
## Footnote
Example: propranolol at beta receptors.
73
What characterizes a reversible competitive antagonist?
Competes with agonists but can be displaced by increasing agonist concentration
## Footnote
Example: naloxone for opioid overdose.
74
Define an irreversible competitive antagonist.
Binds covalently, permanently blocking receptor activity
## Footnote
Example: phenoxybenzamine, an alpha-blocker for pheochromocytoma.
75
What is the difference between orthosteric and allosteric modulation?
Orthosteric binds at the receptor's active site; allosteric binds at a separate site
## Footnote
Example: atropine (orthosteric) at muscarinic receptors; benzodiazepines (allosteric) enhance GABA-A receptor function.
76
What is the effect of lipid solubility on drug absorption?
Lipophilic drugs cross membranes more easily
## Footnote
Lipid solubility is a key factor in how well a drug can be absorbed in the body.
77
In which environments do weak acids and weak bases absorb better?
Weak acids absorb better in acidic environments; weak bases absorb in alkaline environments
## Footnote
For example, aspirin is a weak acid and absorbs well in the stomach, while morphine is a weak base and absorbs well in the intestine.
78
What is first-pass metabolism?
Hepatic metabolism before systemic circulation reduces bioavailability
## Footnote
This process can significantly affect the amount of active drug that reaches the systemic circulation.
79
What are the advantages and disadvantages of oral drug administration?
Most convenient but undergoes first-pass metabolism
## Footnote
This can reduce the bioavailability of the drug.
80
What is the bioavailability of intravenous (IV) drug administration?
100%
## Footnote
IV administration allows for immediate effect and complete absorption into systemic circulation.
81
What is the characteristic of intramuscular (IM) and subcutaneous (SC) drug administration?
Slower, sustained absorption
## Footnote
These routes are often used for vaccines and hormones.
82
Define drug bioavailability.
The fraction of the administered dose reaching systemic circulation unchanged
## Footnote
IV routes have a bioavailability of 100%, while oral routes vary.
83
What factors affect drug distribution?
Blood flow, plasma protein binding, tissue permeability
## Footnote
High blood flow is found in organs like the liver and kidneys, while fat and bone have lower blood flow.
84
What does the central compartment in the two-compartment model include?
Rapidly perfused organs (heart, liver, kidney, blood)
## Footnote
This compartment represents areas where drugs are rapidly distributed.
85
What does the peripheral compartment in the two-compartment model include?
Less-perfused tissues (fat, muscle)
## Footnote
Drugs may take longer to reach equilibrium in these areas.
86
What is first-pass metabolism?
Hepatic metabolism before reaching systemic circulation
## Footnote
It reduces oral drug bioavailability, such as with nitroglycerin.
87
What is the primary effect of first-pass metabolism on drugs?
Reduces oral drug bioavailability
## Footnote
An example is nitroglycerin.
88
What are the main processes involved in Phase 1 biotransformation?
Oxidation, reduction, hydrolysis
## Footnote
These processes are primarily facilitated by CYP enzymes.
89
What is the focus of Phase 2 biotransformation?
Conjugation
## Footnote
Common types include glucuronidation and sulfation.
90
Which CYP enzyme is known for metabolizing many drugs?
CYP3A4
## Footnote
This enzyme can be affected by inhibitors and inducers.
91
Name an inhibitor of CYP3A4.
Ketoconazole
## Footnote
Inhibitors can alter drug metabolism by affecting CYP3A4 activity.
92
Name an inducer of CYP3A4.
Rifampin
## Footnote
Inducers increase the metabolism of drugs processed by CYP3A4.
93
What are the main pathways of drug excretion?
Renal, biliary, pulmonary
## Footnote
Each pathway has distinct mechanisms for eliminating drugs.
94
What processes are involved in renal drug excretion?
Filtration, secretion, reabsorption
## Footnote
These processes occur mainly in the kidneys.
95
How are drugs excreted via the biliary pathway?
From the liver to bile, excreted in feces
## Footnote
This pathway is important for eliminating certain drugs.
96
Which type of drugs are excreted through the pulmonary pathway?
Volatile drugs via respiration
## Footnote
This includes anesthetics and other gases.
97
What is the Therapeutic Index (TI)?
The ratio of the toxic dose (TD₅₀) to the effective dose (ED₅₀). A higher TI indicates a safer drug.
## Footnote
TI is crucial for assessing drug safety.
98
What is the formula for calculating the Therapeutic Index?
TI = TD₅₀ / ED₅₀
## Footnote
This formula helps quantify drug safety.
99
What does a low Therapeutic Index indicate?
A higher risk of toxicity from small dosing errors.
## Footnote
For example, Warfarin has a low TI.
100
What is renal clearance?
The volume of plasma cleared of a drug per unit time, usually in mL/min.
## Footnote
It is a key measure in pharmacokinetics.
101
What factors influence renal clearance?
* Glomerular filtration
* Tubular secretion
* Reabsorption
## Footnote
Each factor plays a role in how drugs are processed by the kidneys.
102
What is the clinical significance of creatinine clearance?
It is used to estimate renal function.
## Footnote
Creatinine clearance is a common measure in clinical settings.
103
What is the definition of plasma half-life (t1/2)?
The time required for the plasma concentration of a drug to decrease by 50%.
## Footnote
This metric is essential for determining dosing schedules.
104
What is the formula for plasma half-life in first-order kinetics?
t1/2 = 0.693 × Vd / CL
## Footnote
Where Vd is the volume of distribution and CL is clearance.
105
Why is plasma half-life important clinically?
It determines dosing intervals.
## Footnote
Drugs with short half-lives require more frequent dosing.
106
What characterizes first-order kinetics?
A constant fraction of drug is eliminated per unit time.
## Footnote
Most drugs follow this kinetic pattern.
107
What characterizes zero-order kinetics?
A constant amount of drug is eliminated per unit time.
## Footnote
This occurs when enzymes become saturated.
108
What is an example of a drug that follows zero-order kinetics?
Ethanol at high doses.
## Footnote
Alcohol dehydrogenase saturation leads to this behavior.
109
What is a drug interaction in the absorption phase?
Chelation reduces drug absorption.
## Footnote
An example is tetracyclines with calcium.
110
What is a drug interaction in the distribution phase?
Plasma protein displacement increases free drug levels.
## Footnote
For example, warfarin and aspirin.
111
What is a drug interaction in the metabolism phase?
CYP inhibition increases drug levels.
## Footnote
An example is grapefruit juice with statins.
112
What is a drug interaction in the excretion phase?
Probenecid inhibits renal clearance of penicillin.
## Footnote
This prolongs the effect of penicillin.
113
What is the primary neurotransmitter of the sympathetic nervous system?
Norepinephrine (NE)
## Footnote
The sympathetic nervous system is often referred to as the 'Fight or Flight' system.
114
What are the effects of the sympathetic nervous system?
↑ Heart rate (HR), ↑ Blood pressure (BP), bronchodilation, pupil dilation (mydriasis)
## Footnote
These effects prepare the body for quick action.
115
What are the key receptors associated with the sympathetic nervous system?
Alpha (α) and Beta (β) adrenergic receptors
## Footnote
These receptors respond to norepinephrine.
116
Give an example of a drug that acts on the sympathetic nervous system.
Albuterol (β₂ agonist)
## Footnote
Albuterol is commonly used for treating asthma.
117
What is the primary neurotransmitter of the parasympathetic nervous system?
Acetylcholine (ACh)
## Footnote
The parasympathetic system is often referred to as the 'Rest and Digest' system.
118
What are the effects of the parasympathetic nervous system?
↓ Heart rate, ↑ digestion, pupil constriction (miosis), bronchoconstriction
## Footnote
These effects promote relaxation and energy conservation.
119
What are the key receptors associated with the parasympathetic nervous system?
Nicotinic & Muscarinic (M) receptors
## Footnote
These receptors bind acetylcholine.
120
Give an example of a drug that acts on the parasympathetic nervous system.
Bethanechol (M agonist)
## Footnote
Bethanechol is used to treat urinary retention.
121
What do preganglionic neurons release in both sympathetic and parasympathetic systems?
Acetylcholine (ACh)
## Footnote
Preganglionic neurons bind to nicotinic receptors in ganglia.
122
What do postganglionic sympathetic neurons release?
Norepinephrine (NE)
## Footnote
An exception is sweat glands, which release acetylcholine.
123
What do postganglionic parasympathetic neurons release?
Acetylcholine (ACh) onto muscarinic receptors
## Footnote
This release leads to various physiological effects.
124
What is a characteristic of nicotinic receptors?
Fast ligand-gated ion channels
## Footnote
They are found in neuromuscular junctions and ganglia.
125
What type of receptors are muscarinic receptors?
GPCRs (G-protein coupled receptors)
## Footnote
Examples include M2 in the heart and M3 in glands.
126
What is the effect of Alpha-1 (α1) adrenergic receptors?
Vasoconstriction
## Footnote
An example drug is phenylephrine.
127
What is the effect of Beta-1 (β1) adrenergic receptors?
Increases heart rate & contractility
## Footnote
An example drug is dobutamine.
128
What do Beta-2 (β2) adrenergic receptors cause?
Bronchodilation & vasodilation
## Footnote
An example drug is albuterol.
129
What is the effect of Alpha-2 (α2) adrenergic receptors?
Decrease NE release
## Footnote
An example drug is clonidine.
130
What is the effect of blocking beta receptors?
↓ Heart rate
## Footnote
Beta-blockers like metoprolol are commonly used.
131
What is the effect of muscarinic blockers?
↓ Secretions
## Footnote
An example drug is atropine.
132
What is the role of Acetylcholinesterase (AChE) inhibitors?
↑ ACh levels
## Footnote
An example is neostigmine.
133
What is the role of Dopamine (DA) in the ANS?
Modulates blood pressure & renal function
## Footnote
Dopamine has various roles in the body.
134
What effect does Serotonin (5-HT) have?
Affects mood, gut motility
## Footnote
Serotonin is a key neurotransmitter in the CNS and gut.
135
What is the function of Nitric Oxide (NO) in the body?
Vasodilator, relaxes smooth muscle
## Footnote
NO plays a significant role in cardiovascular health.
