drug administration and absorption

Question 1

what are the main types of targets for drugs

Answer 1

enzymes, transporters, ion channels and receptors
- most often than not they interact with proteins

Question 2

what is the most common drug target

Answer 2

enzymes

Question 3

what are receptors

Answer 3

proteins that respond to an endogenous messenger by initiating a signal

Question 4

what do selective binding sites act as

Answer 4

molecular switches, switching the cell on and off

Question 5

what are the two types of receptor drugs

Answer 5

agonists and antagonists

Question 6

how does an agonist receptor drug work

Answer 6

it reproduces the effects of endogenous messengers

Question 7

how do antagonists drug receptors work

Answer 7

they block the effects of the endogenous messenger

Question 8

what does the extent to which a drug binds to its
target protein depend on

Answer 8

its local concentration

Question 9

which 3 targets are predominantly targeted by inhibitors

Answer 9

enzymes, transporters and receptors

Question 10

what type of drug target is effected by agonists and antagonists

Answer 10

receptors

Question 11

what does ADME[Tox] stand for

Answer 11

Absorption
Distribution
Metabolism
Excretion
Toxicity

Question 12

define PHARMACOKINETICS

Answer 12

How body controls drug
concentration at site of action

Question 13

define PHARMACODYNAMICS

Answer 13

Effect of drug on target
cell / tissue

Question 14

why is pK important

Answer 14

• Analysis of the behaviour of drugs after administration
• Essential for designing dosing regimen and understanding
  variation in responses between patients

-PK parameters can offer insight into the disposition of the
drug after administration

Question 15

what are the 10 routes of administration

Answer 15

PO, NG, S/L, MR, PR, IV, TOPICAL, OPHTHALMIC, INHALATION , NASAL

Question 16

that route of administration is PO

Answer 16

enteral (oral)

Question 17

that route of administration is NG

Answer 17

nasogastric

Question 18

that route of administration is S/L

Answer 18

sublingual

Question 19

that route of administration is MR

Answer 19

controlled release

Question 20

that route of administration is PR

Answer 20

rectal

Question 21

that route of administration is IV

Answer 21

parenteral

Question 22

that route of administration is TROPICAL

Answer 22

skin

Question 23

that route of administration is OPHTHALMIC

Answer 23

eye

Question 24

that route of administration is INHALATION

Answer 24

lungs

Question 25

that route of administration is NASAL

Answer 25

nose

Question 26

concentration an be found by

Answer 26

measuring the drug concentration of the blood plasma as most drugs circulate via the circulatory system

Question 27

what is a therapeutic window

Answer 27

the therapeutic range where the drug is effective, too much and it becomes toxic too little and its ineffective within the body

Question 28

why are drugs with a narrow therapeutic range difficult to use

Answer 28

patients will need to be monitored more frequently

Question 29

what does MTC stand for

Answer 29

maximum tolerated concentration

Question 30

what does MEC stand for and what does it tell you

Answer 30

minimum efficacious concentration - tells you the minimum amount of a drug that can be taken for it to still be effective

Question 31

why does absorption cause a delay

Answer 31

as the drug has the diffuse into the blood plasma before traveling to the target area

Question 32

what is the half life of a drug

Answer 32

the time taken for the concentration of the drug in the blood to decrease by half

Question 33

what is the half life of oxazepam

Answer 33

5-10 hours

Question 34

what is the half life of diazepam

Answer 34

20-80 hours

Question 35

what is considered when choosing a route of administration

Answer 35

- ease e.g. complient patient - kinetics of the drug (duration of action) - local vs systemic effects

Question 36

define absorption in the administration of drugs

Answer 36

the transfer of a drug from its site of administration to its site of action (PK)

Question 37

define bioavailability in the administration of drugs

Answer 37

The extent to which a drug can overcome the barriers to absorption (including first pass metabolism) and enter the systemic circulation

Question 38

what 2 mechanisms can dugs travel by to enter the blood stream

Answer 38

passive diffusion and active transport

Question 39

how does passive diffusion work during drug absorption

Answer 39

diffuses through phospholipid bilayers - the rate of diffusion depends upon -- the concentration across the membrane --thickness of the membrane -- the surface area of the absorption surface

Question 40

A number of factors affect uptake in the GI tract such as....

Answer 40

-Formulation of drug ( Tablet vs. solution, variation in additives between brands) -Gastrointestinal mobility ( Presence of food or pathology can delay transit time) -Food constituents ( Ca2+binds tetracyclines making them unavailable for absorption) -G secretions & gut wall enzymes (Can destroy / inactivate drugs)

Question 41

what are the advantages using the GI tract as the site of absorption

Answer 41

-Large surface area - Range of pH environments promote uptake of weak acids/bases -Rich blood supply -Long dwell time -Some active transport (e.g. Levodopa taken up by phenylalanine transporter) -Small intestine is major site for absorption

Question 42

why are there differences in rates of absorption from different muscle groups

Answer 42

each muscle group will experience different flows of blood to them

Question 43

The efficiency of absorption can be quantified by what two variables

Answer 43

- Bioavailability (F) - Time to peak (tmax)

Question 44

what is Time to peak (tmax)

Answer 44

a measure of the rate of absorption

Question 45

what is Bioavailability (F) a measure of

Answer 45

a measure of the proportion of dose absorbed (Compared to iv delivery of the same dose)