Pharmacokinetics

Question 1

advantage of rectal route

Answer 1

limited first pass metabolism

Question 2

advantage of sublingual route

Answer 2

avoids first pass metabolism

Question 3

disadvantage inhalation route

Answer 3

variable systemic distribution

Question 4

most common way for drugs to cross membrane

Answer 4

simple diffusion

Question 5

P glycoprotein transports drug ___ of cells

Answer 5

OUT of cells

Question 6

pKa

Answer 6

the pH where exactly 1/2 of weak acid is ionized

Question 7

weak acids weak bases: which better absorbed in stomach

Answer 7

weak acids

Question 8

Ka

Answer 8

rate constant for absorption

Question 9

S

Answer 9

salt factor

Question 10

F

Answer 10

bioavailability

Question 11

how is F measured

Answer 11

(area under the curve) oral / (area under the curve) IV

Question 12

how is amount absorbed measures

Answer 12

S x F x Dose = amount absorbed

Question 13

tissues with highest CO

Answer 13

liver

kidneys = muscle

Question 14

what is alpha

Answer 14

percent of drug unound

Question 15

how is concentration in plasma measured

Answer 15

(S x F x Dose) / volume of distribution

Question 16

how is volume of distribution measured

Answer 16

amount of drug in body / amount of drug in plasma

Question 17

effect of phenobarbital and carbamazepine on CYP450

Answer 17

induces it and speeds up metabolism of other drugs

Question 18

effect of erythromycin and ketoconazole on CYP450

Answer 18

inhibitors, slow metabolism of other drugs

Question 19

effect of grapefruit juice on bioavailability of other drugd

Answer 19

it INCREASES their bioavailbility by inhibiting CYP450

Question 20

what is glucurodination and what phase does it happen in

Answer 20

adding a charge to the drug

- phase II

Question 21

sulfation: phase I or II

Answer 21

II

Question 22

effect of acetylation and methylation on drugs and what phase

Answer 22

makes them less water soluble and inactivates them

- phase 2

Question 23

how do you eliminate protein bound drugs through renal system

Answer 23

NOT through filtration

–> active tubular secretion

Question 24

excretion rate vs clearance

Answer 24

excretion rate: mass eliminated

clearance: rate removed from plasma, mL/min (more important)

Question 25

describe zero order kinetics

Answer 25

constant amount eliminated over time independent of the drug concentration
- ex: alcohol

Question 26

how to administer drugs with long half lives (digoxin)

Answer 26

give a “loading dose” (high dosage) to get it going and then continue with maintenance doses