Drug Action Principles Flashcards
What is a drug?
A chemical substance of known structure, which when administered to a living organism produces a biological effect.
What is pharmacodynamics
The effect of a drug on the body
What is pharmacokinetics?
The effect of the body on a drug
What are the main drug action targets ?
- Enzymes
- Ion channels
- Receptors
- Transporters and carrier molecules
What is an agonist?
A substance that binds to a receptor and causes a change that results in a direct biological response
What is affinity?
How avidly a drug binds to its target site
Ie.
How likely a drug is to bind to its target site
What is an antagonist?
A substance that binds to a receptor and causes no change to it
What is the law of mass action?
States that the rate of a chemical reaction is proportional to the product of the concentrations of the reactants.
(This can determine affinity)
What is potency?
The measure of drug activity….the amount of drug that is required to produce an effect.
What is efficacy?
The drug’s ability to activate the receptor once it has bound to it
What is a partial agonist?
A drug with agonist effects but with sub-maximal (reduced) effect due to reduced efficacy.
Efficacy range is from 0 (antagonist) to 1 (full antagonist)
The values that lie in between are partial agonists.
What is the Ec50 and what does it indicate?
50% of the maximal response of a drug.
The EC50 is a measure of potency.
What is the Emax, what does it indicate?
The maximal response of a drug. It measures the efficacy of a drug.
What is used to test the relationship between drug concentration and its effect?
Organ bath
What is the importance for drugs to have a high specificity for its target?
To reduce drug incidences if side effects.
