Pharmacokinetics & Pharmacodynamics

Question 1

Rapid IV (or oral) bolus:

Answer 1

Vd = F* dose/Cpo (dose over concentration)

Question 2

Elimination rate constant?

Answer 2

K= (Ln C1 - Ln C2)/ (T2-T1)

Question 3

Half life equation?

Answer 3

t 1/2 = 0.693/k

Question 4

What is the bioavailability equation?

Answer 4

Doseiv * AUCev / Doseev * AUCiv

Question 5

What is p-glycoprotein?

Answer 5

CYP3A4 and p-glycoprotein in GI mucosa work together to decrease absorption. Efflux pump that pumps drugs back into the GI lumen (decrease absorption).

Question 6

What to know about zero order kinetics with phneytoin?

Answer 6

Non linear elimination

Question 7

What’s the michaelis menten equation?

Answer 7

Vmax *C/ Km +C

Question 8

What enzymatic pathways in drug metabolism makes up the greatest contribution in the clearance of drugs?

Answer 8

CYP, phase 1 metabolism

Question 9

How do you overcome a competitive drug interaction?

Answer 9

increasing dose of drug A

Question 10

What cytochrome P450 (CYP) enzyme does cyclosporine require for its metabolism?

Answer 10

3A4

Question 11

What is the volume of distribution?

Answer 11

Amount of drug present in the entire body compared to the amount of drug present in the plasma, it does not tell which tissue that drug distributes to. As a general rule drugs that are more lipophilic have larger Vd and drugs that are hydrophilic reside mainly in plasma.

Question 12

What is therapeutic index?

Answer 12

LD50/ED50 and the larger the LD50 versus the ED50 the safer the medication. Medications with a TI>10 are generally considered to have a safer profile.

Question 13

What enzyme is known to be inhibited by diltiazem and verapamil?

Answer 13

CYP3A4.

Question 14

What are the basic componenets of pharmacokinetics?

Answer 14

ADME (absorption, distribution, metabolism, elimination).

Question 15

What is the most common phase 2 metabolic pathway?

Answer 15

UGT.

Question 16

Is rate of elimination in zero order kinetics dependent on drug concentration?

Answer 16

NO. In 1st order yes but not in zero order.

Question 17

Does aspirin and ethanol and phenytoin (after a certain dose) show zero order kinetics?

Answer 17

YES

Question 18

What is normal SCr?

Answer 18

0.7-1.4 mg/dl

Question 19

What are normal cholesterol levels?

Answer 19

LDL <100 mg, Total <200, HDL <40 low, >60 high.

Question 20

What’s a normal creatinine clearance?

Answer 20

120, 90 is stage 2 CKD, 60 is stage 3 CKD, 30 is Stage 4 CKD, 15 is stage 5 CKD (ESRD)

Question 21

Is renal or liver elimination more common?

Answer 21

Liver, renal is second.

Question 22

What is the F value?

Answer 22

Fraction of drug administered that actually made it into the blood or central circulation, the larger the F-value, the greater the percentage that was absorbed and makes it into the central blood circulation.

Question 23

Which drugs bind to alpha-1 acid glycoprotein?

Answer 23

Drugs that are more basic.