intro - basics

Question 1

what is pharmacology

Answer 1

study of drug action -

how drugs interact with interact with living organisms and influences physiological function

Question 2

what is therapeutics

Answer 2

concerned with drug prescribing and treatment of disease. more focused in patient

Question 3

what is pharmacodynamics

Answer 3

what drug does to body

Question 4

what is pharmacokinetics

Answer 4

what body does to drugs

Question 5

what are the 3 qs to ask when considering how drug exerts its effect on body

Answer 5

• where is this effect produced
• what is target of drug
  what is response produced after interaction with this drug

Question 6

what are the 4 types of drug targets

Answer 6

1. receptors
2. enzymes
3. ion channels
4. transport proteins

Question 7

what are some different ways drugs can interact with receptors

Answer 7

electrostatic interactions
hydrophobic interactions
covalent bonds
stereospecific interactions

Question 8

what is affinity

Answer 8

determines strength of binding of drug to receptor

Question 9

what is efficiacy

Answer 9

refers to ability of an individual drug molecule to produce an effect once bound

Question 10

what is potency

Answer 10

refers to concentration/dose of drug required to produce defined effect

Question 11

what is the standard measure of potency

Answer 11

concentration/dose of drug required to produce 50% tissue response

Question 12

what is ec50

Answer 12

half maximal effective concentration

Question 13

what is ed50

Answer 13

half maximal effective dose

Question 14

what is bioavailability

Answer 14

fraction of initial dose that gains access to systemic circulation

Question 15

what are the most commonest forms of drug administration

Answer 15

oral
inhalation
dermal (percutaneous)
intra nasal

Question 16

why is bioavailability likely to be less than 100%

Answer 16

drugs move around like body via

1. bulk flow transfer (i.e in bloodstream)
2. diffusional transfer

Question 17

whether a drug is unionised or not is dependant on…?

Answer 17

1. dissociation constant of that drug, pka

2. the ph in that particular part of body

Question 18

what happens on pka of drug and ph of tissue are equal

Answer 18

drug will be equally ionised and unionised

Question 19

what do most weak acids have a pka of

Answer 19

3-5

Question 20

for weak acids what happens as ph decreases

Answer 20

unionised form dominates

Question 21

for weak acids what happens as ph increases

Answer 21

ionised form dominates

Question 22

what do most weak bases have a pka of

Answer 22

8-10

Question 23

for weak bases what happens when ph decreases

Answer 23

ionised form starts to dominate

Question 24

for weak bases what happens when ph increases

Answer 24

unionised form starts to dominate

Question 25

in pharmacokinetics what are the most important carrier systems relating to drug action

Answer 25

renal tubule
biliary tract
blood brain barrier
gastrointestinal tract

Question 26

what factors affect tissue distribution of a drug

Answer 26

regional blood flow
plasma protein binding
capillary permeability
tissue localisation

Question 27

what is the most important plasma protein which is particularly good at binding acidic drugs

Answer 27

albumin

Question 28

amount of drug that binds to proteins depends on

Answer 28

free drug concentration
affinity of protein binding sites
plasma protein concentration

Question 29

what type of drugs bind particularly well to albumin

Answer 29

acidic drugs

Question 30

what is the major metabolic tissue

Answer 30

the liver

Question 31

what enzymes are mainly responsible for drug metabolism

Answer 31

cytochrome p450

Question 32

what 2 biochemical reactions does drug metabolism involve

Answer 32

phase 1- introduce reactive group to drug

phase 2 - add conjugate to reactive group

Question 33

3 major routes for drug excretion via kidney

Answer 33

1. glomerular filtration
2. active tubular secretion/ reabsorption
3. passive diffusion across tubular epithelium

Question 34

what is the most important method for drug excretion in kidney

Answer 34

active tubular secretion

Question 35

what is oct1

Answer 35

organic cation transporter 1

Question 36

why is oct 1 relevant to pharmacokinetics of orally adminstered drugs

Answer 36

small bowel oct 1 - allows drug to be absorbed
hepatocyte oct1 - allows drug to be distributed
proximal tubule oct 1 - helps excretion