Lecture 3: Pharmacodynamics Flashcards
How is Therapeutic Index calculated?
TI = TD50/ED50
TD 50: median toxic dose
ED 50: median effective dose
The ____ the TI, the safer the drug
Higher
What is drug potency?
Amount of drug required to create specific effect
-represented by ED 50
The ____ the ED 50, the more potent the drug
Lower
What is drug efficacy?
Maximal effect drug can produce
-represented by Emax
In terms of drug receptor binding, covalent bonds are irreversible/reversible?
Irreversible
-which is why most drugs bond non-covalently
Higher affinity for the drug will result in a higher or lower Kd?
Lower Kd
Lower affinity for the drug will result in a higher or lower Kd?
Higher Kd
What is drug selectivity?
Property of a drug determined by its affinities at various binding sites
How is drug selectivity measured?
Kd ratio = [Kd off target]/[Kd target]
What does a higher Kd ratio mean?
More selective drug
What is intrinsic activity?
Ability of drug to change receptor function AND produce physiological response
-only seen in agonists
What is the main difference seen in full agonists vs partial agonists?
- Intrinsic efficacy
- Activated receptors
What is pharmacologic antagonism?
Action at same receptor as endogenous ligand or agonist drug
What is chemical antagonism?
Chemical antagonist makes other drug unavailable
