Warfarin

Question 1

What is the formula for target-specific covalent inhibition

Answer 1

E + I E * I E - I

Ki. k2

Question 2

Maintenance Dose (mg/day) of Warfarin

Answer 2

1.5- 12 mg/day

Question 3

Bioavailability of Warfarin

Answer 3

Greater than 90

Question 4

What is the Tmax of Warfarin

Answer 4

1-2 hours

Question 5

What is the volume of distribution of Warfarin

Answer 5

0.08 - 0.12 (L/kg)

quite small, but don’t be fooled

Question 6

Protein binding % of warfarin

Answer 6

greater than 99%

Question 7

What is the plasma concentration of warfarin

Answer 7

1.5 - 8 (micromol/L)

Question 8

Terminal elimination half-life of warfarin

Answer 8

S warfarin = 24-33 hours
R warfarin = 35-58 hours
(longer due to differences in clearance)

Question 9

Plasma clearance of warfarin

Answer 9

S warfarin = 0.10 - 1.0 (more active form)

R warfarin = 0.07 -0.35

Question 10

RAISED HAND:

Target-mediated drug disposition

Answer 10

Pretty rare but important:
binding to the target influences the disposition of the drug
-potent and specifically acting drugs are substances that are bound with high affinity to pharmacologic target sites such as receptors and enzymes