GENERAL PRINCIPLES OF PHARMACOLOGY - PHARMACODYNAMICS Flashcards
Pharmacodynamics involves the study of
- Biological and therapeutic effects of drugs
- Mechanisms of drug action
- Drug interactions
- Information about unwanted effects
The most appropriate to the term “receptor”
Active macromolecular components of a cell or an organism which a drug molecule has to combine with in order to elicit its specific effect
What does “affinity” mean
A measure of how tightly a drug binds to a receptor
Target proteins which a drug molecule binds are
- Only receptors
- Only ion channels
- Only carriers
An agonist is a substance that
Interacts with the receptor and initiates changes in cell function, producing various effects
If an agonist can produce maximal effects and has high efficacy it’s called
Full agonist
If an agonist can produce submaximal effects and has moderate efficacy it’s called
Partial agonist
An antagonist is a substance that
Binds to the receptors without directly altering their functions
A competitive antagonist is a substance that
Binds to the same receptor site and progressively inhibits the agonist response
The substance binding to one receptor subtype as an agonist and to another as an antagonist is called
Agonist-antagonist
Irreversible interaction of an antagonist with a receptor is due to
Covalent bonds
Mechanisms of transmembrane signaling are
- Transmembrane receptors that bind and stimulate a protein tyrosine kinase
- Ligand-gated ion channels that can be induced to open or close by binding a ligand
- Transmembrane receptor protein that stimulates a GTP binding signal transducer protein (G-protein) which in turn generates an intracellular second messenger
Tick the second messenger of G-protein-coupled (metabotropic) receptor
cAMP
Tick the substance which changes the activity of an effector element but doesn’t belong to second messengers
G–protein
The increase of second messengers’ (cAMP, cGMP, Ca2+ etc.) concentration leads to
Proteinkinases activation and protein phosphorylation.
Tick the substances whose mechanisms are based on interaction with ion channels
- Sodium channel blockers
- Calcium channel blockers
- Potassium channels activators
All of the following statements about efficacy and potency are true
- Efficacy is usually a more important clinical consideration than potency
- Efficacy is the maximum effect of a drug
- Potency is a comparative measure, refers to the different doses of two drugs that are needed to produce the same effect
Efficacy
is the maximum effect of a drug
Potency
is a comparative measure, refers to the different doses of two drugs that are needed to produce the same effect
Therapeutical dose
The amount of a substance to produce the required effect in most patients
Toxic dose
The amount of substance to produce effects hazardous for an organism
Which effect may lead to toxic reactions when a drug is taken continuously or repeatedly
Cumulative effect
What term is used to describe a more gradual decrease in responsiveness to a drug, taking days or weeks to develop?
Tolerance
What term is used to describe a decrease in responsiveness to a drug which develops in a few minutes?
Tachyphylaxis
Tachyphylaxis
Very rapidly developing tolerance
True or False. Drug resistance is a term used to describe the loss of effectiveness of antimicrobial or antitumour drugs.
TRUE
Tolerance and drug resistance can be a consequence of
- Increased metabolic degradation
- ## Change in receptors, loss of them or exhaustion of mediators
True or False. Dependence is often associated with tolerance to a drug, a physical abstinence syndrome, and psychological dependence (craving).
TRUE
The situation when failure to continue administering the drug results in serious psychological and somatic disturbances is called?
Abstinence syndrome
What is the type of drug-to-drug interaction which is connected with processes of absorption, biotransformation, distribution and excretion?
Pharmacokinetic interaction
What is the type of drug-to-drug interaction which is the result of interaction at receptor, cell, enzyme or organ level?
Pharmacodynamic interaction
What phenomenon can occur in case of using a combination of drugs?
Synergism
If two drugs with the same effect, taken together, produce an effect that is equal in magnitude to the sum of the effects of the drugs given individually, it is called as
Additive effect
What does the term “potentiation” mean?
Intensive increase of drug effects due to their combination
The types of antagonism are
Competitive
The term “chemical antagonism” means that
Two drugs combine with one another to form an inactive compound
A teratogenic action is
Negative action on the fetus causing fetal malformation
Characteristic unwanted reaction which isn’t related to a dose or to a pharmacodynamic property of a drug is called
Hypersensitivity
Idiosyncratic reaction of a drug is
Unpredictable, inherent, qualitatively abnormal reaction to a drug
Therapeutic index (TI) is
A ratio used to evaluate the safety and usefulness of a drug for indication
