OBJECT DRUGS

Antiarrhythmics (CYP3A4 Substrates):

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

PRECIPITANT DRUGS

Antidepressants:

• Fluvoxamine (Luvox, etc.)
• Nefazodone

Comment:

Although data are limited, antidepressants that inhibit CYP3A4 could increase the plasma concentrations of these antiarrhythmics. Toxicity including cardiac arrhythmias could result. Assume that all CYP3A4 inhibitors interact until proven otherwise.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative:
• Antidepressants: Citalopram (Celexa), desvenlafaxine (Pristiq), escitalopram (Lexapro), paroxetine (Paxil), sertraline (Zoloft), and venlafaxine (Effexor) appear to have minimal effects on CYP3A4. Fluoxetine (Prozac) appears to be a weak inhibitor of 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.