OBJECT DRUGS

Antipsychotics, Atypical:

• Aripiprazole (Abilify, etc.)
• Brexpiprazole (Rexulti)
• Clozapine (Clozaril, etc.)
• Iloperidone (Fanapt)
• Lurasidone (Latuda)
• Olanzapine (Zyprexa, etc.)
• Quetiapine (Seroquel, etc.)
• Risperidone (Risperdal, etc.)
• Ziprasidone (Geodon)

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:

These antipsychotics are metabolized by CYP3A4; drugs that induce CYP3A4 may reduce their serum levels resulting in loss of efficacy. For example, carbamazepine may reduce olanzapine concentrations by about 50%.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative: Use an alternative to the enzyme inducer if possible. Paliperidone (Invega) is not metabolized by CYP3A4 and could be considered as an alternative.
• Circumvent/Minimize: The manufacturer recommends that the dose of aripiprazole be doubled (to 20-30 mg/day) if CYP3A4 inducers are added. If the enzyme inducer is then discontinued, they recommend that the aripiprazole dose be decreased to 10-15 mg/day.
• Monitor: If it is necessary to use an antipsychotic and enzyme inducer, monitor for altered antipsychotic effect if an enzyme inducer is started, stopped, 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.