DD French equations

Question 1

Bioavailability equation

Answer 1

F = AUCoral/AUCiv

Question 2

T or F: For most drugs, bioavailability is equivalent to the amount of drug in the plasma.

Answer 2

TRUE

Question 3

What does Cp0 mean?

Answer 3

Drug plasma concentration at time of administration

Question 4

Define volume of distribution.

Answer 4

?The size of compartment necessary to account for total drug in body if present at same concentration in body as in plasma (Cp).? Obviously, not all drug stays in the plasma and will distribute out to its tissue target. This typically happens very rapidly, so two compartment modeling is not significant.

Question 5

What does Vd mean?

Answer 5

Volume of distribution

Question 6

Vd equation

Answer 6

Vd (L) = Dose [mg] / Cp0 [mg/L]

Question 7

Calculate Vd: Dose = 120 mg, Cp0 = 3 mg/L

Answer 7

Vd = 40 L

Question 8

If Vd = 40 L, how would you describe its distribution?

Answer 8

Distributed though all the water in the body (plasma, interstitial, intracellular).

Question 9

If Vd = 3 L, how would you describe its distribution?

Answer 9

Only in the plasma

Question 10

If Vd = 12 L, how would you describe its distribution?

Answer 10

In the plasma and interstitial fluid (3 L and 9 L, respectively)

Question 11

If Vd = 100 L, how would you describe its distribution?

Answer 11

Sequestered at tissue sites. More common for lipid soluble drugs.

Question 12

Loading dose equation

Answer 12

Loading dose = Cp * Vd

Question 13

T or F: A patient?s body weight (size) does not affect Vd.

Answer 13

FALSE

Question 14

Name 4 factors that influence Vd (other than patient size).

Answer 14

1.) Sites requiring drug to pass through cells, not between. 2.) The pH of body compartment with the drug. 3.) Lipid solubility of the non-ionized form of the drug. 4.) Drug binding to plasma proteins.

Question 15

T or F: Only free drug is diffusible.

Answer 15

TRUE

Question 16

T or F: Kidney tubular excretion is the same as tubular secretion.

Answer 16

FALSE. Tubular excretion describe filtration at the glomerulus between cell. Secretion is a more active process that happens through cells.

Question 17

Henderson-Hasselbalch Equation

Answer 17

pH-pKa = log ([unprotonated form] / [protonated form])

Question 18

Describe how drugs are eliminated.

Answer 18

Kidney excretion, renal tubule secretion, hepatic biotransformation, biliary secretion, sweat (minimal)

Question 19

T or F: Drug binding to plasma protein is a huge concern, especially when a drug is given alone.

Answer 19

FALSE. Typically will not be a clinical concern unless given with another drug that changes plasma protein binding kinetics with the result of increased metabolism, excretion, or toxicity.

Question 20

Which drugs from unit 1 should not be combined due to alteration of plasma protein binding?

Answer 20

Salicylate and methotrexate

Question 21

What does protein binding do to a drug (4 things)?

Answer 21

Reduces metabolism and excretion, decreases availability to traget (active drug), decreases distribution, decreases ability to enter CNS.

Question 22

Elimination equation

Answer 22

C2=C1 * e-ket

Question 23

Half-life equation

Answer 23

t1/2 = 0.693/ke

Question 24

Clearance equation

Answer 24

CL = Vd * ke

Question 25

Continuous infusion equation

Answer 25

Cp = Infusion rate/CL

Question 26

Multiple Intermittent Dosing equaiton

Answer 26

CL = (Maintenance dose/time)/Cp

Question 27

Therapeutic index equation

Answer 27

TI = LD50/ED50

Question 28

Standard Safety Margin equation

Answer 28

SSM = [(LD1/ED99) - 1] X 100

Question 29

What this mean: e/Emax = [D]/[EC50+D]

Answer 29

Defines the hyperbolic curve for drug effect