Dose Response Curves

What is a dose?

A quantity of a medicine or drug taken or recommended to be taken at a particular time

What happens when we increase a dose?

Bigger effect up to a certain point

What do drugs ending with -lol usually indicate?

drug ending with -lol - beta blocker

What is a dose - response relationship?

As conc increases, response increases until it plateaus - could be due to receptors being used up

Higher dose will not give more response

What is the

k1 = rate of association of DR complex

K2 = rate of dissociation of DR complex

kd = equilibrium dissociation complex

What is a dose-response experiment?

Addition of an agonist to a cell, tissue , organ or organism

Doubling of conc at each conc increase

Response recorded

What is affinity?

Kd value is a measure of affinity

conc where 50% receptors are occupied

\
obtained from occupancy assay’s

* labelled agonist
* circulation of bound vs free drug
* receptors reach Bmax (binding) where no more binding takes place
* 50% of this is Kd value

\
can be extrapolated from binding curves

makes the assumption that max response is caused by max receptor occupancy

ED50 can therefore be assumed to be Kd in tissues we know receptors are fully occupied

\

y axis is percentage response

x axis dose

ed 50 = -5.7

pd2 = 2x10-6

what is ld50

The conc of drug required to be lethal to 50% of cells, tissues, organs and organisms