Antiarrhythmics

Question 1

Amiodarone Brand Names

Answer 1

Cordarone, Pacerone, Nexterone

Question 2

Amiodarone Indications/Dosages

Answer 2

recurrent V-Fib and hemodynamically unstable V-tach in patients who are unresponsive or cannot tolerate other antiarrhythmics: loading dose of 800-1600mg/day (in 3 doses) for 1-3 weeks, done in hospital setting, followed by 400mg/day

Question 3

Amiodarone Mechanism

Answer 3

lengthens cardiac action potential
shows some noncompetitive alpha- and beta-blocking capabilities (Class I and II), and negative chronotropic effects (Class IV)
Prolongs intranodal conduction and refractoriness of AV node

Question 4

Amiodarone Antiarrhythmic Class

Answer 4

Class III

Question 5

Amiodarone PK

Answer 5

maximum plasma concentrations in 3-7h
Onset of action can take 2 days to 3 weeks
food increases bioavailability

Question 6

Amiodarone metabolism

Answer 6

Metablized by CYP3A4 to active metabolite

Also metabolized by CYP2C8

Question 7

Amiodarone Drug Interactions

Answer 7

May increase effects of warfarin, phenytoin, digoxin, quinidine, procainamide, disopyramide, fentanyl, flecainide, lidocaine, and cyclosporine
Cimetidine and grapefruit juice may increase amiodarone serum levels
Cholesyramine, St. John’s Wort, and phenytoin may decrease amiodarone serum levels
May have additive effects with B-blockers
AV block and hypotension increased when used with CCB’s

Question 8

Amiodarone CI/Precautions

Answer 8

CI: patients with cardiogenic shock, marked sinus bradycardia, second or third degree AV block unless functioning pacemaker available
hypotension and bradycardia are related to rate of infusion, can be minimized by slowing infusion

Question 9

Amiodarone Monitorin

Answer 9

Baseline chest x-ray and PFT’s, and every 3-6 months
QTc prolongation during treatment
Regular LFT’s should be performed

Question 10

Amiodarone Pregnancy Category

Answer 10

D

Question 11

Amiodarone ADR’s

Answer 11

Serious: hypotension, cardiogenic shock, cardiac arrest, congestive heart failure, bradycardia, LFT abnormalities, Pulmonary fibrosis, V-tach, and AV block
Less serious: N/V, photosensitivity, fatigue, ataxia, dizziness, anorexia, constipation, visual disturbances

Question 12

Amiodarone Patient Education

Answer 12

take consistently in regards to meals, preferably with meals
notify physician immediately if experience SOB, wheezing, coughing, passing dark-color urine, yellowing of eyes, chest or stomach pain, abnormal heart rhythm, or faintness
avoid overexposure to sunlight, use sunscreen and appropriate clothing
check with pharmacist before adding OTC meds
avoid grapefruit and grapefruit juice