Amiodarone

Question 1

What two formulations can amiodarone be absorbed with?

Answer 1

IV and PO

Question 2

What percent is IV absorbed?

Answer 2

100%

Question 3

Is amiodarone PO absorbed fast or slow?

Answer 3

Very slow - incomplete absorption

Question 4

Is it best to take PO amiodarone with food or without food?

Answer 4

With food - it increases the rate of absorption

Question 5

Where is amiodarone mainly distributed?

Answer 5

To lipophilic tissues

Question 6

(T/F) - Amiodarone has enterohepatic circulation

Answer 6

TRUE - long half life

Question 7

How is amiodarone metabolized?

Answer 7

By CYP3A4 in the liver

Question 8

Does amiodarone inhibit any enzymes and/or transporters?

Answer 8

CYP3A4, 2D6, 2C9 and P-gp

Question 9

Which drugs need to be automatically decreased when amiodarone is concomitantly given with them?

Answer 9

Digoxin

Warfarin

Question 10

By how much percent should digoxin be adjusted when given with amiodarone?

Answer 10

Decrease by 50%

Question 11

By how much percent should warfarin be adjusted when given with amiodarone?

Answer 11

Decrease by 25%

Question 12

Phenytoin is a drug that interacts with amiodarone. What will happen to the levels of amiodarone when given with phenytoin, increase or decrease? By how much percent?

Answer 12

Increase by 50%

Question 13

In which route is amiodarone mainly eliminated/excreted?

Answer 13

Biliary

Question 14

What is the chronic half-life of amiodarone?

Answer 14

53 days

Question 15

What are some factors that can affect the elimination of amiodarone?

Answer 15

• Elderly

- Cirrhosis

Question 16

The onset of action for amiodarone is when?

Answer 16

Variable - 1 to 3 weeks

Question 17

What are the therapeutic levels for amiodarone? Why is it a questionable clinical value?

Answer 17

0.5 to 2 mg/mL

It’s questionable because amiodarone does not hang out in the blood as much - it likes fatty tissue

Question 18

What is the loading dose (LD) of amiodarone in an oral formulation? How many grams should it get up to for it to be effective?

Answer 18

1.2 to 1.8 g/day - divided doses

10 grams

Question 19

What is the LD of amiodarone in an IV formulation? How many grams should it get up to for it to be effective?

Answer 19

5 to 7 mg/kg over 30-60 mins followed by 1.2 to 1.8 g/day

10 grams

Question 20

What is the maintenance dose (MD) of amiodarone?

Answer 20

200 to 400 mg/day

Question 21

How is amiodarone IV converted to PO if it has been less than or equal to 1 week of usage?

Answer 21

800 to 1600 mg/day for 1-2 weeks then MD 200 to 400 mg/day

Question 22

How is amiodarone IV converted to PO if it has been 1 week to less than 3 weeks of usage?

Answer 22

600 to 800 mg/day for 1-2 weeks then MD 200 to 400 mg/day

Question 23

How is amiodarone IV converted to PO if it has been more than 3 weeks of usage?

Answer 23

Begin MD 200 to 400 mg/day

Question 24

How is amiodarone PO converted to IV?

Answer 24

PO MD will be 30 to 70%

Question 25

What are some cardiac toxicities involved with amiodarone?

Answer 25

- Bradycardia | - AV block or torsades de pointes

Question 26

What factors affect cardiac toxicities of amiodarone in an IV form?

Answer 26

Rate and concentration of drug

Question 27

(T/F) - If amiodarone has a concentration > 2 mg/mL, it should be administered in a peripheral line to avoid phlebitis

Answer 27

FALSE - in a central line

Question 28

To reduce the risk of cardiac toxicities of amiodarone in an IV form, how should IV be administered?

Answer 28

With an IV filter and mixed in glass

Question 29

What are some pulmonary toxicities involved with amiodarone?

Answer 29

- Pulmonary fibrosis - Hypersensitivity pneumonitis - Pulmonary inflammation - Interstitial and alveolar pneumonitis

Question 30

What are some hepatic toxicities involved with amiodarone?

Answer 30

- Transient elevation in LFT (15-30%) | - Clinical hepatitis and cirrhosis (< 3%)

Question 31

What are some thyroid toxicities involved with amiodarone?

Answer 31

Hypothyroidism (20%) | Hyperthyroidism (3%)

Question 32

What are some ocular toxicities involved with amiodarone?

Answer 32

- Corneal microdeposits (70-100%) | - Optic neuropathy (< 1%)

Question 33

What are some dermatologic toxicities involved with amiodarone?

Answer 33

- Photosensitivity (25-75%)

Question 34

What tests should be done in patients w/ amiodarone at baseline?

Answer 34

- EKG - Pulmonary function tests - Chest X-ray - LFT - Thyroid function - Eye exam

Question 35

What tests should be done in patient w/ amiodarone every 6 months?

Answer 35

- LFT - Thyroid function - Eye exam

Question 36

What tests should be done yearly in patients w/ amiodarone?

Answer 36

- Chest X-ray - EKG - Pulmonary function tests (if symptoms occur)

Question 37

Is dronedarone a better option than amiodarone?

Answer 37

No - causes more potential harm than benefits