Digoxin ADME

Question 1

Is digoxin absorption complete?

Answer 1

Nope

Question 2

What kind of absorption does digoxin have?

Answer 2

Passive and non-saturable

Question 3

Where does digoxin pre-systemic metabolism occur?

Answer 3

GI tract

Question 4

The bioavailability of digoxin is limited by what?

Answer 4

Rate of dissolution

Question 5

Digoxin bioavailability decreases with what drugs?

Answer 5

Kaolin, Al/Mg antacids, cholestyramine

Question 6

Digoxin bioavailability increases with what drugs?

Answer 6

Erythromycin, TTCs

Question 7

Digoxin bioavailability decreases with what disease state?

Answer 7

Diarrhea

Question 8

Digoxin is highly bound to what?

Answer 8

Tissue

Question 9

Vd of digoxin is reduced in what disease states?

Answer 9

Hyperkalemia and renal failure

Question 10

Does digoxin have a slow or fast rate of dissolution?

Answer 10

Slow

Question 11

The highest concentrations of digoxin are found where?

Answer 11

Heart, kidneys, intestine, liver, stomach, and skeletal muscle

Question 12

Does obesity alter the Vd of digoxin?

Answer 12

Nope

Question 13

Digoxin PK is characterized with how many compartment models?

Answer 13

3 (but assume a 1 CM model for calculations)

Question 14

Vd of digoxin is increased in what disease state?

Answer 14

Hypokalemia

Question 15

Elimination of digoxin is decreased with what disease state?

Answer 15

Renal failure and pGP

Question 16

True or false: renal clearance of digoxin exceeds GFR

Answer 16

True

Question 17

How much of a digoxin dose is excreted unchanged in the urine?

Answer 17

~50%

Question 18

After half of the dose is excreted unchanged in the urine, where is the rest of the digoxin metabolized and eliminated?

Answer 18

Biliary secretion

Question 19

Therapeutic range of digoxin

Answer 19

0.5-2.0ng/ml

Question 20

What concentrations can be treated as Cssavg concentrations after dosing?

Answer 20

Concentrations taken >6 hours after a dose