Pharmacodynamics - Drug Receptor Interactions Flashcards
What is the purpose of secondary messengers?
amplify cellular signals to trigger a cellular response cascade
what describes the tendency of a drug to combine with a particular kind of receptor
affinity
what does affinity rely on
chemical structure to create a strong binding force (covalent/ ionic bond)
what refers to the maximal effect the drug can produce
efficacy
what does drug efficacy depend on
-conformational changes in receptors
-drug-receptor complexes
just because a drug has efficacy, will there always be an observable side effect?
no - efficacy only measures the changes made by a drug to a receptor
clinical efficacy will show the side effects while intrinsic efficacy does not
what possesses affinity for a particular receptor, causing a change that results in an observable effect
agonist
what is a drug that blocks the response produced by an agonist
antagonist
does an antagonist have affinity for a receptor
yes
does an antagonist have intrinsic efficacy
no
how does an antagonist have clinical efficacy but no intrinsic effects
blocking a response (to show no response) is a clinical sign
– NOTHING HAPPENING IS A SIGN –
antagonists do not cause a conformational change in the receptor is it blocking
what are the 3 types of antagonism
- receptor antagonism
- physiologic antagonism
- chemical antagonism
what has intrinsic efficacy but produces an opposite effect
inverse agonist
on a dose-response curve, where would you find efficacy
peak of the curve (maximal response)
what is the concentration of a drug required to achieve a particular effect
potency
if a drug has high potency, what type of dose is required/ needed
small dose
what is the relationship between potency and affinity?
high potency = high affinity
- higher binding to a receptor creating more responses
what does potency depend on
affinity and efficacy of a receptor
what type of drug produces only a single effect
selective drug
what is an example of a selective drug and why
heparin – it’s only effect is an anticoagulant
what type of drug acts only on 1 type of receptor but can have multiple effects
specific drugs
how is a specific drug able to have multiple responses with only acting on 1 type of receptor
these receptors can be found throughout the body in different organs
what is an example of a specific drug
atropine
what type of drug has several mechanisms of action
non-specific drug
what is an example of a non-specific drug
acepromazine
causes sedation, antiemetic, hypotension and hypothermia
