Concomitant Drug
Class/Name |
Examples
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Clinical Comment
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Pharmacodynamic Interactions
|
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QT Prolonging Drugs
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class I and III antiarrhythmics, lithium, certain phenothiazines, tricyclic antidepressants, certain fluoroquinolone and macrolide antibiotics, azole antifungals, halogenated inhalation anesthetic agents
|
Increased risk of Torsade de Pointes. Avoid concomitant use.
|
Negative Chronotropes
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digoxin, beta blockers, verapamil, diltiazem, clonidine, ivabradine
|
Potentiates the electrophysiologic and hemodynamic effects of amiodarone, resulting in bradycardia, sinus arrest, and AV block. Monitor heart rate.
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Pharmacokinetic Interactions
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CYP450 Inhibitors
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grapefruit juice, certain fluoroquinolone and macrolide antibiotics, azole antifungals, cimetidine, certain protease inhibitors
|
Increased exposure of amiodarone. Avoid concomitant use.
|
CYP450 Inducers
|
St. John's Wort
|
Reduced amiodarone serum levels.
|
Cyclosporine
|
Increased plasma levels of cyclosporine have been reported resulting in elevated creatinine, despite reduction of cyclosporine dose. Monitor cyclosporine
drug levels and renal function with concomitant use. |
|
Cholestyramine
|
Reduced amiodarone serum levels.
|
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Antiarrhythmics
|
quinidine, procainamide, flecainide
|
Reserve concomitant use for patients who are unresponsive to a single agent. Antiarrhythmic metabolism inhibited by amiodarone. Initiate antiarrhythmic at a lower than usual dose and monitor patient carefully. Reduce dose levels of previously administered antiarrhythmic by 30 to 50% for several days after transitioning to oral amiodarone. Evaluate continued need for antiarrhythmic.
|
Digoxin
|
Increased digoxin concentration. Reduce digoxin by half or discontinue. If continued, monitor for evidence of toxicity.
|
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HMG-CoA Reductase Inhibitors
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simvastatin, lovastatin, atorvastatin
|
Increased plasma concentration of HMG- CoA reductase inhibitor.
Limit the dose of lovastatin to 40 mg. Limit the coadministered dose of simvastatin to 20 mg. Lower starting dose of other CYP3A4 substrates may be required. |
Warfarin
|
Potentiates anticoagulant response and can result in serious or fatal bleeding. Coadministration increases prothrombin time by 100% after 3 to 4 days. Reduce warfarin dose by one-third to one-half and monitor prothrombin times.
|
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Phenytoin
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Increased steady-state levels of phenytoin. Monitor phenytoin levels.
|
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Hepatitis C Direct
Acting Antiviral |
sofosbuvir
|
Cases of symptomatic bradyarrhythmia requiring pacemaker insertion have been reported in patients on oral maintenance amiodarone who initiated therapy with sofosbuvir.
|
CYP3A Substrate
|
lidocaine
|
Sinus bradycardia has been reported with oral amiodarone in combination with lidocaine given for local anesthesia.
Monitor heart rate. A lower starting dose of lidocaine may be required. |
CYP3A Substrate
|
fentanyl
|
Fentanyl in combination with amiodarone may cause hypotension, bradycardia, and decreased cardiac output.
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