segars PK lectures

Question 1

when treating your pts a drug may be handled in up to 4 possible stages

Answer 1

Adsorption
Distribution
Metabolism
Elimination

Question 2

how do gel caps affect time for dissolution

Answer 2

they decrease the time of dissolution for faster absorption

Question 3

types of passive absorption

Answer 3

filtration: through pores or channels, determined by osmotic/hydrostatic pressure differential

diffusion

• through cell membranes
• determined by concentration gradient, most commonly utilized by drug

Question 4

ionization status depends on 2 factors

Answer 4

pka of medication (weak acid or weak base)
pH of membrane-gradient
(where the drug is in the body like stomach or intestine)

Question 5

pka

Answer 5

propensity of a compound to donate (acids) or accept (bases) protons

Question 6

when pKa = pH then

Answer 6

there is a 50/50 ratio of ionized:unionized

Question 7

if a weak acid goes to a area of body that is more acidic then what happens to unionization

Answer 7

unionization goes up

Question 8

if a weak base goes to area of body that is more basic then what happens to unionization

Answer 8

it goes up

Question 9

what represents the unbound fraction of a drug

Answer 9

a (alpha)

Question 10

what will a high protein binding drug with low displacement have when it comes to relative change when new drug displaces

Answer 10

a very big change in relative change

Question 11

renal elimination- 3 main processes

Answer 11

passive glomerular filtration
-blood flow dependent

passive tubular diffusion

• prox or distal tubules
• ionization and concentration status dependent

active tubular secretion
-weak acids/bases secreted into proximal tubules

Question 12

Tmax

Answer 12

onset of activity

Question 13

Cmax

Answer 13

max drug concentration

Question 14

Cmin

Answer 14

minumum drug concentration

Question 15

MEC

Answer 15

minimum effective concentration

Question 16

MTC

Answer 16

max therapeutic concentration

Question 17

bioavailabilty

Answer 17

F (no units)
-fraction of a dose that enters circulation
-extent of absorption not rate
IV = 1

Question 18

factors determining bioavailability

Answer 18

ionization status in various locales
first pass and GI metab
Dissolution

Question 19

salt factor

Answer 19

will be 1

Question 20

3 items determining amt of drug absorbed

Answer 20

dose
bioavailability
salt factor

multiply all 3 together to figure how much drug got in

Question 21

ideal body weight of female

Answer 21

45 kg + (2.3 kg X (height in inches - 60 inches))

Question 22

ideal body weight of male

Answer 22

50 kg + (2.3 kg X (height in inches - 60 inches))

Question 23

what does tau represent

Answer 23

dosing interval in hours