OBJECT DRUGS

Antipsychotics:

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

PRECIPITANT DRUGS

Enzyme Inhibitors: (CYP3A4)

• Amiodarone (Cordarone, etc.)
• Amprenavir (Agenerase)
• Aprepitant (Emend)
• Atazanavir (Reyataz)
• Conivaptan (Vaprisol)
• Cyclosporine (Neoral, etc.)
• Darunavir (Prezista)
• Delavirdine (Rescriptor)
• Diltiazem (Cardizem, etc.)
• Grapefruit
• Indinavir (Crixivan)
• Nefazodone
• Nelfinavir (Viracept)
• Ritonavir (Norvir)
• Saquinavir (Invirase)
• Telaprevir (Incivek)
• Verapamil (Isoptin, etc.)

Comment:

These antipsychotics are metabolized by CYP3A4; drugs that inhibit CYP3A4 may increase their serum levels.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative: Use an alternative to the enzyme inhibitor if possible.
• Calcium channel blockers: Calcium channel blockers other than diltiazem and verapamil are unlikely to inhibit CYP3A4.
• Grapefruit: Orange juice does not appear to inhibit CYP3A4.
• Antipsychotic: 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 reduced to one-half the usual dose if CYP3A4 inhibitors or CYP2D6 inhibitors are added. If the inhibitor is then discontinued, they recommend that the aripiprazole dose be increased to the usual dosage.
• Monitor: Be alert for altered effect of the antipsychotic if CYP3A4 inhibitors are started, stopped, or changed in dosage.