Pharmacodynamics II Flashcards
What does selectivity refer to in drug actions?
Selectivity refers to a drug’s ability to preferentially affect certain receptors or biological pathways over others.
True or False: A drug with high selectivity will have many side effects.
False
Fill in the blank: The strength of the interaction between a drug and its receptor is known as _____ .
affinity
What is affinity in the context of drug actions?
Affinity is a measure of how tightly a drug binds to its receptor.
Which term describes the amount of drug needed to produce a desired effect?
potency
True or False: A more potent drug requires a higher dose to achieve the same effect as a less potent drug.
False
What does efficacy refer to in drug actions?
Efficacy refers to the maximum effect a drug can produce, regardless of dose.
Multiple Choice: Which of the following affects a drug’s efficacy? A) Dose B) Drug-receptor interaction C) Affinity
B) Drug-receptor interaction
What is the relationship between potency and dose?
Higher potency means a lower dose is required to achieve the desired effect.
True or False: A drug can be potent but have low efficacy.
True
Fill in the blank: A drug that activates a receptor and produces a biological response is called an _____ .
agonist
What is an antagonist in pharmacology?
An antagonist is a drug that binds to a receptor but does not activate it, blocking the action of agonists.
Multiple Choice: Which property would be most important for a drug designed to target a specific disease with minimal side effects? A) Selectivity B) Efficacy C) Potency
A) Selectivity
How does a drug’s selectivity impact its therapeutic window?
Higher selectivity generally leads to a wider therapeutic window, reducing the risk of side effects.
What is the significance of a drug’s half-life in relation to its potency?
Half-life affects how long a drug remains active in the body, which can influence its overall potency in achieving therapeutic effects.
True or False: All drugs with high affinity are also highly potent.
False
Fill in the blank: The _____ is the dose at which a drug produces 50% of its maximum effect.
ED50
What does a dose-response curve illustrate?
A dose-response curve illustrates the relationship between drug dose and the magnitude of its effect.
Multiple Choice: Which of the following factors does NOT influence drug selectivity? A) Chemical structure B) Dose C) Receptor distribution
B) Dose
What is the difference between intrinsic activity and efficacy?
Intrinsic activity refers to the ability of a drug to activate a receptor, while efficacy refers to the maximum response achievable.
True or False: Efficacy is always proportional to potency.
False
Fill in the blank: A drug with low affinity will require _____ concentrations to achieve its effects.
higher
What is a competitive antagonist?
A competitive antagonist is a substance that binds to the same site as an agonist but does not activate the receptor, preventing the agonist from eliciting a response.
Multiple Choice: Which term best describes the effectiveness of a drug at its target receptor? A) Affinity B) Efficacy C) Potency
B) Efficacy
What is the primary goal of drug design in relation to selectivity?
The primary goal is to create drugs that selectively target specific receptors or pathways to minimize side effects.
What is an agonist?
An agonist is a substance that activates a receptor to produce a biological response.
What is a partial agonist?
A partial agonist is a substance that binds to a receptor and produces a response, but not to the full extent that a full agonist would.
What is an inverse agonist?
An inverse agonist is a substance that binds to a receptor and induces a response opposite to that of an agonist.
True or False: An agonist can only activate a receptor.
True
Fill in the blank: A partial agonist has __________ activity compared to a full agonist.
lower
Which type of agonist would decrease the activity of a receptor?
Inverse agonist
Multiple Choice: Which of the following is an example of an agonist?
Morphine
What is the primary difference between a full agonist and a partial agonist?
A full agonist fully activates the receptor, while a partial agonist activates it only partially.
True or False: Partial agonists can act as antagonists in the presence of a full agonist.
True
What happens when an inverse agonist binds to a receptor?
It stabilizes the receptor in an inactive state, reducing its activity.
Fill in the blank: Agonists typically __________ the physiological response of a receptor.
increase
Multiple Choice: Which of the following describes the action of an inverse agonist?
It reduces receptor activity.
What role do agonists play in pharmacology?
They are used to mimic the action of natural substances in the body.
True or False: All agonists lead to an increase in the physiological response.
False
What is the effect of a partial agonist in a system with no other agonists present?
It will activate the receptor but not to the maximum effect.
True or False: Inverse agonists can be used therapeutically to counteract the effects of agonists.
True
Multiple Choice: Which type of drug would you use to decrease the effect of an overactive receptor?
Inverse agonist
What is a common characteristic of all three types: agonist, partial agonist, and inverse agonist?
They all bind to receptors.
Fill in the blank: The presence of a __________ can change the efficacy of a partial agonist.
full agonist
What kind of response does a full agonist produce?
A maximal response.
True or False: Inverse agonists can only act on certain types of receptors.
True
What is the significance of understanding the differences between agonists, partial agonists, and inverse agonists in drug development?
It helps in designing drugs that target specific receptor activities.
Multiple Choice: Which of the following best describes a partial agonist’s effect in the presence of a full agonist?
It competes for the receptor and may reduce the overall effect.
What therapeutic applications can inverse agonists have?
They can be used to treat conditions caused by receptor overactivity.
Fill in the blank: An agonist’s ability to activate a receptor is referred to as its __________.
efficacy
True or False: Partial agonists can have both agonist and antagonist properties depending on the context.
True
What is a reversible competitive antagonist?
A reversible competitive antagonist is a substance that binds to a receptor and can be displaced by the agonist, allowing for competitive inhibition.
What characterizes an irreversible competitive antagonist?
An irreversible competitive antagonist binds permanently to the receptor, preventing the agonist from eliciting a response.
True or False: Reversible antagonists can be displaced by increasing the concentration of an agonist.
True
Fill in the blank: An irreversible antagonist forms a __________ bond with the receptor.
covalent
What effect does a reversible competitive antagonist have on the dose-response curve?
It shifts the dose-response curve to the right without changing the maximum response.
What happens to the dose-response curve with an irreversible antagonist?
It reduces the maximum response and may also shift the curve to the right.
Which type of antagonist typically requires a higher concentration of agonist to achieve a response?
Reversible competitive antagonist
Multiple Choice: Which of the following is an example of a reversible competitive antagonist? A) Naloxone B) Aspirin C) Propranolol
C) Propranolol
True or False: Irreversible antagonists can be outcompeted by agonists.
False
What is the primary mechanism of action for reversible competitive antagonists?
They compete with agonists for binding to the same receptor site.
What type of antagonist would be more effective in a situation requiring quick reversal of effects?
Reversible competitive antagonist
Short Answer: Name a common irreversible antagonist used in clinical settings.
Phenoxybenzamine
Fill in the blank: The binding of a reversible antagonist is __________.
non-covalent
True or False: The effects of irreversible antagonists can be overcome by administering more agonist.
False
What happens to receptor availability when an irreversible antagonist is administered?
The receptor becomes permanently unavailable for agonist binding.
Multiple Choice: Which type of antagonist can lead to long-lasting effects even after it is removed from the system? A) Reversible B) Irreversible
B) Irreversible
Short Answer: What type of bond is primarily formed by irreversible antagonists?
Covalent bond
Fill in the blank: The use of __________ can help reverse the effects of a reversible competitive antagonist.
agonists
What is the clinical significance of understanding the difference between reversible and irreversible antagonists?
It helps in choosing the appropriate treatment for patients based on the desired duration of action.
True or False: Reversible antagonists can lead to a complete blockade of receptor activity.
False
What happens to the efficacy of an agonist in the presence of a reversible antagonist?
The efficacy is reduced, but not eliminated.
Multiple Choice: Which antagonist type would be preferred for a temporary blockade in anesthesia? A) Reversible B) Irreversible
A) Reversible
Short Answer: What is the primary therapeutic use of irreversible antagonists?
To provide long-lasting effects in conditions like hypertension.
Fill in the blank: __________ is an example of a reversible antagonist that competes with acetylcholine.
Atropine
What is the effect of increasing the concentration of an agonist when a reversible antagonist is present?
It can restore the effect of the agonist.
True or False: Both reversible and irreversible antagonists can be used in pharmacological treatments.
True
What is a common clinical scenario for using reversible competitive antagonists?
To manage acute allergic reactions.
What is orthosteric modulation?
Orthosteric modulation refers to the direct binding of a ligand to the active site of a receptor.
What is allosteric modulation?
Allosteric modulation involves the binding of a ligand to a site other than the active site, resulting in a change in receptor activity.
True or False: Orthosteric modulators can only activate receptors.
False. Orthosteric modulators can either activate or inhibit receptors.
Fill in the blank: Allosteric modulators can enhance or inhibit the effects of ___________ at the active site.
orthosteric ligands
Which type of modulation typically has a more selective effect on receptor activity?
Allosteric modulation
What is the main advantage of allosteric modulators over orthosteric modulators?
Allosteric modulators can provide more nuanced control over receptor activity and reduce side effects.
Which type of modulation is more likely to lead to receptor desensitization?
Orthosteric modulation
Multiple choice: Which of the following is an example of orthosteric modulation? A) Binding of a neurotransmitter to a receptor B) Binding of a drug to an allosteric site C) Binding of a hormone to a receptor’s regulatory site
A) Binding of a neurotransmitter to a receptor
What does the term ‘allosteric site’ refer to?
An allosteric site is a location on a receptor where a ligand can bind, apart from the active site, influencing receptor function.
True or False: Allosteric modulators can only act as inhibitors.
False. Allosteric modulators can act as either enhancers or inhibitors.
What is a potential drawback of using orthosteric drugs?
Orthosteric drugs may cause receptor desensitization or downregulation over time.
Fill in the blank: ___________ modulation can lead to changes in receptor conformation without directly blocking the active site.
Allosteric
What is a key characteristic of orthosteric ligands?
They compete with other ligands for the same binding site on the receptor.
Multiple choice: Which statement is true regarding allosteric modulators? A) They bind exclusively to the active site B) They can alter the receptor’s response to orthosteric ligands C) They are always antagonists
B) They can alter the receptor’s response to orthosteric ligands
What is the effect of an allosteric enhancer?
An allosteric enhancer increases the efficacy of the orthosteric ligand.
True or False: Allosteric modulators can only be small molecules.
False. Allosteric modulators can be both small molecules and larger biomolecules.
What role do orthosteric modulators play in pharmaceuticals?
Orthosteric modulators are commonly used as drugs to directly activate or inhibit receptor activity.
Fill in the blank: Allosteric modulation can lead to ___________ responses to stimuli.
differential
What type of modulation is often associated with fewer side effects?
Allosteric modulation
Multiple choice: Which of the following can be a result of orthosteric modulation? A) Increased specificity B) Competitive inhibition C) Non-competitive enhancement
B) Competitive inhibition
What is a common application of allosteric modulation in drug design?
To create drugs that selectively enhance or inhibit receptor activity without competing with natural ligands.
True or False: Allosteric modulators can change the shape of the receptor.
True.
What is one reason researchers explore allosteric sites for drug development?
Allosteric sites provide opportunities for more selective and safer therapeutic agents.
What happens when an allosteric inhibitor binds to a receptor?
It decreases the receptor’s response to an orthosteric ligand.
