Agonism - Using drugs to make things happen Flashcards
What is pharmacokinetics?
Pharmacokinetics describes what the body does to drugs - involves drugs getting into, around and out of the body - absorption, distribution and metabolism
What is pharmacodynamics?
Pharmacodynamics describes what the drug does to the body - relates to the concentration and the amount of effect it has
What is the therapeutic window?
The dose amount that gives clinical efficacy
What is the difference between a partial agonist and a full agonist?
A full agonist binds all of the receptors
What is potency?
The concentration required for a drug to be effective
What is EC50?
The drug concentration required for 50% of maximum effect
What are some of the benefits of partial agonists?
Doesn’t cause as much desensitisation, doesn’t cause as much dependency, effects only desired tissues instead of all tissues
What are the three steps in drug action?
Binding, activation, transduction
What is pharmacological efficacy?
The strength of receptor activation - full agonists have high efficacy and partial agonists have low efficacy - full agonists have more units of second messenger per receptor
What is clinical efficacy?
The strength of the beneficial effect - not related to whether it is a full or partial agonist
What is the effect of desensitisation on agonist potency and efficacy?
If a drug is full agonist there is receptor reserves, but not if the drug is a partial agonist. If the receptors become desensitised because of over use then partial agonists may no longer have any potency because receptors are no longer responding to them. May also cause the drug to become a competitive antagonist because competing with endogenous ligands.
