OBJECT DRUGS

Carbamazepine (Tegretol, etc.)

PRECIPITANT DRUGS

Antidepressants:

• Fluoxetine (Prozac, etc.)
• Fluvoxamine (Luvox, etc.)
• Nefazodone

Comment:

Inhibition of CYP3A4 by fluvoxamine or nefazodone may result in carbamazepine toxicity. With most CYP3A4 inhibitors, carbamazepine toxicity usually occurs within 2-3 days of starting the inhibitor, but the effect of fluoxetine on carbamazepine is less consistent and may be delayed by 1-2 weeks or longer. It may involve enzymes in addition to CYP3A4, perhaps CYP2C19.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative: Sertraline (Zoloft), citalopram (Celexa), escitalopram (Lexapro), venlafaxine (Effexor), and paroxetine (Paxil) appear less likely to inhibit CYP3A4 than fluvoxamine. Little is known about the effects of other antidepressants on carbamazepine.
• Monitor:If alternatives are not appropriate, consider reducing carbamazepine dose. Monitor for altered carbamazepine effect if enzyme inhibitors are started, stopped, or changed in dosage. Symptoms of carbamazepine toxicity include nausea, vomiting, dizziness, drowsiness, headache, diplopia, and confusion.