L3 - Principles of drug action

Question 1

In vitro experiment

Answer 1

Drug effects are studied on a piece of tissue dissected from an animal (or human), and kept ALIVE outside the body

Question 2

In vivo experiment

Answer 2

drug effects are studied in the living animal or human

Question 3

Ex vivo experiment

Answer 3

inject a drug into the animal and keep it alive for several months/years

Question 4

Drug doses expression in in vitro experiment

Answer 4

mole per litre

Question 5

Drug doses expression in in vivo experiment

Answer 5

weight of drug per weight of animal ( 1mg/kg)

Question 6

Maximal “Effect” (Emax)

Answer 6

it is the maximum response a drug can produce

Question 7

EC50

Answer 7

the molar concentration of a drug that produces 50% of the maximum response for that drug

Question 8

potency ratio (M)

Answer 8

comparing two EC50 values for 2 drugs with the same action allow us to calculate their relative potencies

Question 9

potency ratio formula

Answer 9

EC50 (test) / EC50 (standard)

Question 10

log potency ratio formula

Answer 10

logEC50(test) - logEC50(standard)

Question 11

Therapeutic index

Answer 11

it is the ratio between the toxic dose of a drug and the dose producing the desired therapeutic effect

Question 12

Therapeutic index formula

Answer 12

TD50 / ED50

Question 13

Potency definition

Answer 13

it is a measure of the concentration range of a drug over which it is effective (a lower EC50 corresponds a higher potency)