Antagonism

Question 1

antagonist ?

Answer 1

drug that prevents the response of agonist

Question 2

5 classes of antagonist?

Answer 2

1. chemical - chemically alter agonist
2. pharmacokinetic - reduction in amount of drug absorbed, or metabolised of exreted
3. physiological - interaction of 2 drugs with opposing actions
4. competitivie inhibitor - same site as agonist
5. non comp - different set but blocks step

Question 3

how do you overcome antagonism?

Answer 3

increase conc of agonist as reduces number of receptors available

Question 4

What does it mean if the dose ratio is 2?

Answer 4

need twice a much agonist to overcome

Question 5

how to extract the KD from schild plot?

Answer 5

take the inverse log of the x intercept e.g. if it is 9 = logx10 tp the power 9

Question 6

PA2 meaning?

Answer 6

measure of affinity = -1x log KD it is always positive

Question 7

irrerversible comp inhibitor -

Answer 7

covalently bonds, max maintained for a while due to the receiver receptors when run out then max declines

Question 8

what does the dose ratio mean and how is it calculated

Answer 8

factor by which the concentration of the agent has to be multiplied by to produce a response when there is an antagonist present

calculation - EC50 after antagonist / EC50 before
higher the dose ratio - the more specific the antagonist is