Pharmacokinetics Concepts

Question 1

1kg = ? Lbs

Answer 1

1 kg = 2.2 lbs

Question 2

How many mLs in:

1 tsp

1 tbsp

1 oz

Answer 2

1 tsp = 5 mL

1 tbsp = 15 mL

1 oz = 30 mL

Question 3

How many mLs in:

1 qt

1 pint

1 gallon

Answer 3

1 qt = 946 mL

1 pint = 473 mL

1 gallon = 3.79 L (4 quarts or 8 pints)

Question 4

“Qam” dosing

Answer 4

Every morning

Question 5

“Qpm” dosing

Answer 5

Every evening

Question 6

“Qhs” dosing

Answer 6

Every night at bedtime

Question 7

“Ac” dosing

Answer 7

Before meals

Question 8

“Pc” dosing

Answer 8

After meals

Question 9

Administer od

Answer 9

Right eye

Question 10

Administer os

Answer 10

Left eye

Question 11

Administer ou

Answer 11

Both eyes

Question 12

Administer ad

Answer 12

R ear

Question 13

Administer as

Answer 13

L ear

Question 14

Administer au

Answer 14

Both ears

Question 15

“Gtt”

Answer 15

Drops

Question 16

U.d.

Answer 16

As directed

Question 17

T.r.a.

Answer 17

To run at

Question 18

K.v.o

Answer 18

Keep vein open

Question 19

CaCl lactated ringer

Answer 19

20mg/100mL

Question 20

KCl lactated ringer

Answer 20

30mg/100mL

Question 21

NaCl lactated ringer

Answer 21

600mg/100ml

Question 22

sodium lactate - lactated ringer

Answer 22

310mg/100mL

Question 23

In terms of drug distribution, what does “alpha” represent?

Answer 23

The unbound fraction (%)

Aka the active drug

Question 24

T/F: drugs that have low protein binding are less affected by drug-drug interactions

Answer 24

True

Question 25

What method of absorption is most commonly utilized by drugs at the cellular level?

Answer 25

Diffusion through cell membrane — mediated by concentration gradient

Question 26

Describe the solubility of ionized compounds

Answer 26

Lower lipid solubility; higher water solubility

Do not easily diffuse across lipid bilayer of membranes

Question 27

Describe solubility of unionized compounds

Answer 27

Higher lipid solubility; lower water solubility

Easily diffuse across lipid bilayer

Question 28

2 important areas of the body where pH varies and commonly impacts ionization status are GI tract and kidneys. What does this mean for highly ionized drugs in these areas?

Answer 28

Highly ionized drugs do NOT readily get absorbed into GI tract or re-absorbed from renal tubules back into systemic circulation

Highly ionized drugs are ELIMINATED

Question 29

What is the primary difference between carrier-mediated transport and diffusion?

Answer 29

Carrier-mediated is an active process that requires ENERGY

Question 30

What method of active transport differs from the rest?

Answer 30

Facilitated diffusion - because it does not require energy or proceed against gradients

Question 31

Difference between phase 1 and phase 2 reactions utilized in biotransformation

Answer 31

Phase 1 = formation of new or modified functional group or cleavage of chemical-groups (e.g., oxidation, reduction, hydrolysis) — typically CYP450 enzymes

Phase 2 = involve conjugation (covalent linkages; glucuronidation, sulfation, acetylation) with an endogenous substance (e.g., glucuronic acid, sulfate, glycine,etc.)

Question 32

Main sites of action of CYP450 enzymes

Answer 32

Liver
GI tract
Brain
Kidney

Question 33

Describe first-order kinetics

Answer 33

Rate of elimination is proportional to plasma concentration (Cp)

Aka amount of drug removed per unit time will vary proportionately with Cp

The percentage of total amount of change in the Cp remains constant over time

Question 34

Describe zero-order kinetics

Answer 34

Rate of elmination is not proportional to Cp — amount of drug removed per unit time stays the same over time

The percentage of total amount of change in Cp is NOT constant over time

Question 35

What does “F” represent in pharmacokinetics

Answer 35

Bioavailability

represents fraction of a dose that enters circulation — always considered F=1 for IV route

Note that it does not describe rate of absorption

Question 36

What term is the equivalency factor derived from potency, and represents percentage of a dose that equals the primary serum-assessed drug

Answer 36

Salt factor (S)

Question 37

3 items that determine amount of drug absorbed

Answer 37

Dose
Bioavailability
Salt factor