OBJECT DRUGS

Antiarrhythmics (CYP3A4 Substrates):

• Amiodarone (Cordarone, etc., etc.)
• Disopyramide (Norpace, etc.)
• Dronedarone (Multaq)
• Quinidine (Quinidex)

PRECIPITANT DRUGS

Enzyme Inhibitors:

• Amiodarone (Cordarone)
• Amprenavir (Agenerase)
• Aprepitant (Emend)
• Atazanavir (Reyataz)
• Boceprevir (Victrelis)
• Ceritinib (Zykadia)
• Cobicistat (Stribild)
• Conivaptan (Vaprisol)
• Cyclosporine (Neoral, etc.)
• Darunavir (Prezista)
• Delavirdine (Rescriptor)
• Dronedarone (Multaq)
• Grapefruit
• Indinavir (Crixivan)
• Lomitapide (Juxtapid)
• Mifepristone (Korlym)
• Nelfinavir (Viracept)
• Ritonavir (Norvir)
• Saquinavir (Invirase)
• Telaprevir (Incivek)

Comment:

Although data are limited, any CYP3A4 inhibitor could increase the plasma concentrations of these antiarrhythmic drugs. Toxicity including cardiac arrhythmias could result. Assume that all CYP3A4 inhibitors interact until proven otherwise. The mifepristone product information states that concurrent use of quinidine is contraindicated.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative:
• Grapefruit: Orange juice does not appear to inhibit CYP3A4.
• Monitor: Monitor for altered antiarrhythmic response if the CYP3A4 inhibitor is initiated, discontinued, or changed in dosage. Monitor for ECG changes indicating antiarrhythmic toxicity, and measure antiarrhythmic plasma concentrations as needed.