Pharmacology- Intro to Drug Action Flashcards
Pharmacodynamics
What a drug does to the body ie biological effects and mechanism of action
pharmacokinetics
What the body does to a drug ie ADME
Define drug
Any single synthetic, or natural, substance of known structure used in the treatment, prevention, or diagnosis of disease.
can be everyday or illicit substances
Define a medicine
A chemical preparation containing one, or more, drugs used with the intention of causing a therapeutic effect. Medicines usually include agents additional to the active drug
What makes a drug useful as a therapeutic agent?
It must act with a degree of selectivity
Selectivity
The ability of a drug to distinguish between different molecular targets in the body
Main targets for drugs
- enzymes
- carrier molecules ie transporters and pump
- ion channels
- receptors
- RNA
- DNA
Receptors
Macromolecules on/ within cells which mediate biological actions of hormones, nt and other endogenous substances
Agonists
drugs which bind to a receptor, producing a cellular response
possess affinity and efficacy
eg adrenaline
Antagonists
drugs which reduce/ block the action of agonists by binding the same receptor
possess affinity but lack efficacy
beta blockers
Affinity
strength of association between a ligand and receptor
Binding step
Efficacy
an agonist’s ability to evoke a cellular response
Activation step
Specificity
absolute drug selectivity
Relationship between agonist concentration and receptor occupancy
hyperbolic ie agonist conc and the fraction of receptors occupied in a population increase correspondingly
Linear relationship between concentration/ dose and effect
hyperbolic
Semi-logarithmic relationship between concentration/ dose and effect
Sigmoidal
EC50
concentration of agonist which elicits a half maximal effect
Effect of competitive antagonists on concentration curve
parallel rightward shift
maximum change remains unchanged
Effect of non-competitive antagonists on concentration curve
depress slope and maximum response
do not cause rightward shift
Effect of increasing competitive antagonists on concentration curve
Progressive rightward shift of agonist concentration response curve on concentration axis, but no depression of slope, or maximum response
Effect of increasing non-competitive antagonists on concentration curve
Progressive depression of maximum response and slope, but no shift of agonist concentration response curve on the concentration axis
receptors are mostly which type of molecule?
protein macromolecules
do partial agonists have a lower or higher efficacy than full agonists?
Partial agonists have a lower efficacy than full agonists
