Pharmacodynamics Flashcards
Partial Agonists:
can never produce a maximal response at a receptor
True
Partial Agonists:
Cause a parallel shift in the semilogarithmic dose response curve
False
Partial Agonists:
Bind irreversibly to receptor sites
False
Partial Agonists:
Generally have a lower affinity for the receptor than the agonist
False
Partial Agonists:
If a partial agonist has the same affinity for a receptor as the agonist, it’s equilibrium constant will be the same
True
The following are example of hepatic enzyme inducers:
Ranitadine
False
The following are example of hepatic enzyme inducers:
Erythromycin
False
The following are example of hepatic enzyme inducers:
Phenytoin
True
The following are example of hepatic enzyme inducers:
Amiodarone
False
The following are example of hepatic enzyme inducers:
Cigarette smoking
True
The following are examples of hepatic enzyme inhibitors:
Amiodarone
True
The following are examples of hepatic enzyme inhibitors:
Carbemazepine
False
The following are examples of hepatic enzyme inhibitors:
Metronidazole
True
The following are examples of hepatic enzyme inhibitors:
Fludrocortisone
False
The following are examples of hepatic enzyme inhibitors:
Ceftriaxone
False
Concerning drug dose response and response:
A plot of % response against drug concentration gives a sigmoid shape
False
Concerning drug dose response and response:
Antagonists must have a higher receptor affinity than agonists
False
Concerning drug dose response and response:
Intrinsic activity determines maximal response
True
Concerning drug dose response and response:
Maximal response occurs only when all the receptor sites are occupied
False
Concerning drug dose response and response:
Partial agonism implies low receptor affinity
False
The efficacy (or intrinsic activity) of a drug: Is greater for drug A if A is effective in a dose of 100 micrograms than for drug B if B is effective in a dose of 100 milligrams
False
The efficacy (or intrinsic activity) of a drug: Is a measure of its theraputic index
False
The efficacy (or intrinsic activity) of a drug: Is a measure of the amount of a drug required to produce a given affect
False
The efficacy (or intrinsic activity) of a drug: Describes the ability of a drug to produce its therapeutic effect
True
The efficacy (or intrinsic activity) of a drug: Is a measure of the bioavailability of a drug
False
Genetic polymorphisms of drug metabolism:
Exhibit inter-ethnic differences
True
Genetic polymorphisms of drug metabolism:
Are not associated with adverse effects
False
Genetic polymorphisms of drug metabolism:
Are dependent on the pharmacological actions of the drug
False
Genetic polymorphisms of drug metabolism:
Are due to altered gene expression
True
Genetic polymorphisms of drug metabolism:
Are not clinically important for drugs eliminated by the kidney
True
Metabolism of the following drugs are affected by the acetylator status of the individual:
Hydralazine
True
Metabolism of the following drugs are affected by the acetylator status of the individual:
isoniazid
True
Metabolism of the following drugs are affected by the acetylator status of the individual:
Propranolol
False
Metabolism of the following drugs are affected by the acetylator status of the individual:
Amiodarone
False
Metabolism of the following drugs are affected by the acetylator status of the individual:
Digoxin
False
Regarding log-dose response curves:
Potency is the ability of a drug to produce maximal response
False
Regarding log-dose response curves:
A partial agonist binds to the receptor with a lower affinity than the agonist
False
Regarding log-dose response curves:
In the presence of a competitive antagonist the log dose-response curve for an agonist shows a parallel shift to the right
True
Regarding log-dose response curves:
In the presence of a non-competitive antagonist the log dose-response curve for an agonist shows a parallel shift to the left
True
The following interactions are antagonistic:
Naloxone and dextropropoxphe
True
The following interactions are antagonistic:
Acetylcysteine and paracetamol
True
The following interactions are antagonistic:
Atenolol and salbutamol
True
The following interactions are antagonistic:
Protamine and warfarin
False
The following interactions are antagonistic:
Tranexamic acid and streptokinase
True
Non-competitive agonists:
Move the log dose-response curve for a drug in the right in a non-parallel manner
True
Non-competitive agonists:
Reduce the gradient of the log dose-response curve
True
Non-competitive agonists:
Have an effect unrelated to the agonist plasma concentration
False
Non-competitive agonists:
Prevent maximum agonist response
True
Non-competitive agonists:
Display surmountability
False
The following drugs act via enzyme inhibition:
Allopurinol
True
The following drugs act via enzyme inhibition:
Physostigmine
True
The following drugs act via enzyme inhibition:
Indomethacin
True
The following drugs act via enzyme inhibition:
Meptazinol
False
The following drugs act via enzyme inhibition:
Enoximone
True
An hereditary enzyme abnormality may lead to altered metabolism of:
Propofol
False
An hereditary enzyme abnormality may lead to altered metabolism of:
Isoniazid
True
An hereditary enzyme abnormality may lead to altered metabolism of:
Thiopentone
False
An hereditary enzyme abnormality may lead to altered metabolism of:
Suxamethonium
True
An hereditary enzyme abnormality may lead to altered metabolism of:
Atracurium
False
Competitive antagonists:
Shift the log dose-response curve right
True
Competitive antagonists:
Can bind to a different receptor site than the agonist
False
Competitive antagonists:
At the neuromuscular junction, weak antagonists tend to have a faster onset
True
Competitive antagonists:
Shift the log dose-response down
False
Competitive antagonists:
Are compared with one another by the degree of reduction in maximal response
False
Regarding partial agonists:
If an agonist has an intrinsic activity of <1, it is termed a partial agonist
True
Regarding partial agonists:
If given in very large doses partial agonists may achieve a full response
False
Regarding partial agonists:
If given in combination with a full agonist, they can act as an antagonist
True
Regarding partial agonists:
If given in combination with a full agonist, they can act as an agonist
True
Regarding partial agonists:
If given alone, partial agonists can act as agonists or antagonists
False
Regarding drug-receptor interactions:
Affinity refers to how well a drug binds to its receptor
True
Regarding drug-receptor interactions:
Intrinsic activity refers to the magnitude of effect once a drug has bound to receptor
True
Regarding drug-receptor interactions:
A drug with high affinity will produce a large response
False
Regarding drug-receptor interactions:
Partial agonists have a low receptor affinity
False
Regarding drug-receptor interactions:
Antagonists will have high receptor affinity
True
A drug that is 98% protein bound:
Will double its free drug concentration if protein binding is decreased to 96%
True
A drug that is 98% protein bound:
Will show 2% increase in free drug concentration if protein binding falls 2%
False
A drug that is 98% protein bound:
must have a pKa >7.4
False
A drug that is 98% protein bound:
might be diazepam
True
A drug that is 98% protein bound:
might be midazolam
True
The following are examples of pharmacokinetic drug interactions:
Lithium and thiazide diuretics
True
The following are examples of pharmacokinetic drug interactions:
Digoxin and amiodarone
True
The following are examples of pharmacokinetic drug interactions:
Phenytoin and cimetidine
True
The following are examples of pharmacokinetic drug interactions:
Beta blokers and verapamil
False
The following are examples of pharmacokinetic drug interactions:
Ethanol and diazepam
False
The following drugs exhibit tachyphylaxis:
GTN
True
The following drugs exhibit tachyphylaxis:
Ephidrine
True
The following drugs exhibit tachyphylaxis:
Succinylcholine
False
The following drugs exhibit tachyphylaxis:
Trimetaphan
True
The following drugs exhibit tachyphylaxis:
Hydralazine
False
The rate of diffusion of a drug across a membrane is dependent upon:
The drug concentration gradient across the membrane
True
The rate of diffusion of a drug across a membrane is dependent upon:
Fick’s law
True
The rate of diffusion of a drug across a membrane is dependent upon:
Dalton’s law
False
The rate of diffusion of a drug across a membrane is dependent upon:
The surface area of the membrane
True
The rate of diffusion of a drug across a membrane is dependent upon:
The degree of ionisation of the drug
True
The following are examples of physiological antagonism
Morphine and naloxone
False
The following are examples of physiological antagonism
Fentanyl and doxapram
True
The following are examples of physiological antagonism
Morphine and pentazocine
False
The following are examples of physiological antagonism
Ritodrine and syntocinon
True
The following are examples of physiological antagonism
Frusemide and amiloride
True
Partial agonists:
Act as both agonists and antagonists
True. Partial agonists act as agonists in isolation, but can act antagonistically when given in combination with a full agonist.
Partial agonists:
Have similar intrinsic activity to full agonists
False. Full agonists have an intrinsic activity of 1, whereas a partial agonists have an intrinsic activity of <1.
Partial agonists:
Include buprenorphine
True
Partial agonists:
Include pentazocine
False. Pentazocine is a mixed agonist-antagonist.
Partial agonists:
Include clozapine
True. Clozapine is a partial agonist at D2 receptors.
Antagonists:
Have intrinsic activity, but lack affinity
False. They have affinity, but an intrinsic activity of zero.
Antagonists:
Competitive antagonism reduces Emax
False. Maximum efficacy (Emax) remains the same, but the dose-response curve is shifted to the right. Non-competitive antagonism reduces Emax
Antagonists:
Competitive antagonists bind to a site distal to the receptor involved
False. Competitive antagonists compete for a receptor with agonists. Non-competitive antagonists bind to a distal site, and induce a change at the receptor.
Antagonists:
Non-competitive antagonism is overcome by increasing agonist dose
False. This is competetive antagonism.
Antagonists:
May also act as agonists
True. Mixed agonists-antagonists can act as agonists at some receptors and antagonists at others e.g. pentazocine.
Regarding the log dose-response curve:
The ED50 is the drug concentration that induces a response halfway between zero and maximum
False. ED50 refers to the dose of drug - this question defines the Effective Concentration 50.
Regarding the log dose-response curve:
Therapeutic index = Lethal Dose 50 / Effective Dose 50
True
Regarding the log dose-response curve:
Drugs with a narrow therapeutic window do not require monitoring
False. Drugs with a narrow therapeutic window often require close monitoring as the risk of reaching toxic levels is greater.
Regarding the log dose-response curve:
It is shifted to the left with the addition of a competitive antagonist
False. The curve is shifted to the right as a higher dose of agaonist is required to produce an equivalent response.
Regarding the log dose-response curve:
Potency is represented by the height of the curve
False. It is represented by the position of ED50, much like the position of P50 on the oxy-Hb dissociation curve.
Receptors and 2nd messengers:
G-protein receptors have alpha, beta and delta subunits
False. G-proteins consist of alpha, beta and gamma subunits.
Receptors and 2nd messengers:
Insulin receptors are G-protein coupled
False. The Insulin receptor utilises tyrosine kinase.
Receptors and 2nd messengers:
Opioid receptors are G-protein coupled
True
Receptors and 2nd messengers:
cAMP is a hydrophobic molecule
False. It is hydrophilic.
Receptors and 2nd messengers:
Nitric oxide acts via cAMP
False. It acts via cGMP.
The following antagonists have agonist properties:
Ranitidine
False. It is an H2-receptor antagonist.
The following antagonists have agonist properties:
Prazosin
False. It is a selective alpha1-adrenoreceptor blocker.
The following antagonists have agonist properties:
Pindolol
True. It is a non-selective Beta-blocker with partial beta-agonist activity. It also has partial agonist / antagonist activity at the 5-HT1A receptor.
The following antagonists have agonist properties:
Naltrexone
False. It is an opioid receptor antagonist.
The following antagonists have agonist properties:
Xameterol
True. It is a mixed beta-agonist/antagonist.
Regarding negative exponential processes:
The rate of decay varies with time
True. In an exponential process the rate of change of a variable is proportional to the magnitude of the variable at that moment in time. In a negative exponential process, the rate of decay is decreasing with increasing time.
Regarding negative exponential processes:
The time constant is longer than the half-life
True. An exponential process is said to be complete after 3 time constants, as opposed to 5 half-lives.
Regarding negative exponential processes:
The time constant is the natural logarithm of the half-life
False. The time constant is the reciprocal of the rate constant.
Regarding negative exponential processes:
Is converted into a straight line by a semi-log plot
True. This is true of other exponential processes also. It allows for easier interpretation.
Regarding negative exponential processes:
The time constant is the time for the process to complete if the rate continued at its initial speed
True. It can also be defined as the time taken for an exponential process to fall to 37% or 1/e of its previous value.
Receptors:
Drug affinity depends on the attraction between receptors and drugs
True. Affinity is the ability of a ligand to bind to a specific receptor.
Receptors:
Thyroid hormones bind to cell surface receptors
False. They bind to intracellular receptors.
Receptors:
Acetylcholine receptors have 2 alpha and 2 beta subunits
False. The adult acetylcholine receptor has 2 alpha subunits (to which acetylcholine binds), a beta subunit, a delta subunit and an episilon subunit (this is replaced by a gamma subunit in the foetus).
Receptors:
Midazolam acts at GABAb receptors
False. It acts at GABAa receptors.
Receptors:
Nicotinic hormones bind to intracellular receptors
False. Nicotinic receptors are type 1 receptors according to Urquhart’s calssification - membrane bound ligand gated ion channels.
Regarding chemical bond strength:
Van der Waals > Hydrogen > Ionic > Covalent
False
Regarding chemical bond strength:
Covalent > Ionic > Hydrogen > Van der Waals
False
Regarding chemical bond strength:
Covalent > Hydrogen > Ionic > Van der Waals
False
Regarding chemical bond strength:
Ionic > Covalent > Hydrogen > Van der Waals
True
Regarding chemical bond strength:
Van der Waals > Hydrogen > Covalent > Ionic
False
The following processes are mediated by cAMP:
Decreased heart rate
True. Both increases and decreases in heart rate are mediated via cAMP. Beta1-adrenoreceptors are G-protein coupled - their stimulation causes increased cAMP and subsequent tachycardia. Muscarinic M2 receptors are Gi type g-protein coupled receptors and when stimulated decrease cAMP and reduce heart rate via opening of potassium channels
The following processes are mediated by cAMP:
Liver carbohydrate metabolism
True. Beta2-adrenoreceptors are G-protein coupled, and their stimulation causes increased cAMP and subsequent glycogenolysis (also increases insulin and glucagon secretion).
The following processes are mediated by cAMP:
Increased contractility
True. Beta1-adrenoreceptors are G-protein coupled, and their stimulation causes increased cAMP and subsequent increase in contractility.
The following processes are mediated by cAMP:
Triglyceride breakdown
True. Beta2-adrenoreceptors are G-protein coupled, and their stimulation causes increased cAMP and subsequent lipolysis (also increases insulin and glucagon secretion). Beta 3-adrenoreceptors are also G-protein coupled and increase cAMP - they help regulation lipid metabolism.
The following processes are mediated by cAMP:
Smooth muscle relaxation
True. Beta2-adrenoreceptors are G-protein coupled, and their stimulation causes increased cAMP and subsequent smooth muscle relaxation.
Which of the following may alter drug response:
Tachyphylaxis
True. Tachyphylaxis is defined as a decreased response following a single administration of a drug.
Which of the following may alter drug response:
Changes in receptor number
True. Whether this affects drug response depends on the degree of change in receptor number, and whether the drug response involves spare receptors (i.e. a full response is obtained despite some receptors not being occupied).
Which of the following may alter drug response:
Hypersensitivity reactions
True
Which of the following may alter drug response:
Idiosyncratic drug responses
True. Such reactions are not related to known pharmacological properties of a drug (i.e. not a common side effect, they are dose independent). They include anaphylaxis and anaphylactoid reactions.
Which of the following may alter drug response:
Tolerance
True. Tolerance is the decreased responsiveness following repeated drug adminsitration.
