Pharmacodynamics Flashcards
What do drugs do?
- alter the rate of bodily functions
- modulate intrinsic physiological functions
Law of Mass Action
-rate of association of a molecule to a surface is equal to the rate of dissociation of the molecule from the surface
Adsorption isotherm depends on the interaction of which 2 molecules?
ligand and receptor
Receptor occupation theory
a bimolecular interaction where a drug binds reversibly to the receptor so equilibrium is reached
Orthosteric agonist
a drug agonist activating the same receptor site as that acted upon by a physiological agonist
What happens to a dose-response curve when transferred to a logarithmic plot?
sigmoidal
How do you find potency of drug using a dose response curve?
50% response across and then down to the dose concentration
What is the intrinsic activity of a drug?
the ability of a ligand to activate a receptor and the signal transduction system linked to that receptor
What is the equation for intrinsic activity and how can you interpret the results?
Emax of an agonist/Emax of full agonist
alpha=1 – full agonist
alpha >0,<1 – partial agonist
alpha=0 – antagonist
Why would an agonist be classified as a partial agonist?
- slow on/off receptor kinetics
- partial receptor activation
What are spare receptors?
The percentage of receptors that are left over after reaching maximal efficacy
Which has more of an effect on signal transduction activation: affinity for receptor or intrinsic activity?
affinity
The potency of a drug is dependent on what?
- affinity (binding of the receptor)
- efficacy (response elicited by drug-bound receptor)
What are common allosteric antagonists?
activating antibodies (IgG)
Allosteric antagonists have uniformly ______ intrinsic activity.
less