Pharmacology

Question 1

CYP3A4 inducers

Answer 1

D - Dexamethasone
R - Rifampicin
J - St. John's Wart
A - Chronic alcohol
P - Phenytoin and carbimazole

Question 2

CYP3A4 inhibitors

Answer 2

G - Grapefruit juice
R - Ritonavir
A - Azoles
C - CCBs
E - Erythromycin/clarithromycin
O - Omeprazole
C - Cimetidine

Question 3

How many half lives does it take to reach steady state?

Answer 3

5 half lives (97%)

Question 4

Formula for half life of a drug

Answer 4

T1/2= 0.693 x Vd/Cl

Question 5

Formula to adjust dose for renal impairment

Answer 5

Dose rate (pt)/dose rate (normal) = (1-fu) + (fu x (calculated CrCl/normal CrCl))

Question 6

What is the formula for maintenance infusion rate of a drug?

Answer 6

• DR = CL x Css
○ DR = Maintenance dose rate (mg/hour)
○ CL = Clearance (L/hour)
○ Css = steady state drug concentration (mg/L)

Question 7

What is the formula for the loading dose of a drug?

Answer 7

Loading dose =Vdx target plasma concentration

Question 8

What is the formula for volume of distribution?

Answer 8

Vd = amount of drug in body/plasma drug concentration

Question 9

What is the formula for bioavailability?

Answer 9

Non-IV AUC/ IV AUC