OBJECT DRUGS

Antidepressants, Tricyclic:

• Amitriptyline (Elavil)
• Amoxapine (Asendin)
• Clomipramine (Anafranil)
• Desipramine (Norpramin)
• Doxepin (Sinequan, etc.)
• Imipramine (Tofranil, etc.)
• Nortriptyline (Aventyl, etc.)
• Protriptyline (Vivactil)
• Trimipramine (Surmontil)

PRECIPITANT DRUGS

Enzyme Inducers:

• Barbiturates
• Bosentan (Tracleer)
• Carbamazepine (Tegretol, etc.)
• Dabrafenib (Tafinlar)
• Dexamethasone (Decadron, etc.)
• Efavirenz (Sustiva)
• Lumacaftor (Orkambi)
• Nevirapine (Viramune, etc.)
• Oxcarbazepine (Trileptal, etc.)
• Phenytoin (Dilantin, etc.)
• Primidone (Mysoline)
• Rifabutin (Mycobutin)
• Rifampin (Rifadin, etc.)
• Rifapentine (Priftin)
• St. John's Wort

Comment:

Enzyme inducers may gradually reduce the serum levels and effect of imipramine, desipramine, amitriptyline, and probably other tricyclic antidepressants (TCA). TCAs differ in their metabolism by CYP450 isozymes; hence, the magnitude of TCAs interaction with enzyme inducers may vary as well.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative: While it would be prudent to use an alternative to the enzyme inducer, suitable alternatives with equivalent therapeutic effects are not available for most enzyme inducers. One could also consider a non-TCA antidepressant, but many of them may also be susceptible to enzyme induction.
• Monitor: Monitor for altered tricyclic antidepressant effect if enzyme inducer is initiated, discontinued, or changed in dosage. Keep in mind that enzyme induction is usually gradual and may take days to weeks for onset and offset, depending on the specific inducer.