OBJECT DRUGS
PRECIPITANT DRUGS
Antimicrobials:
- Ciprofloxacin (Cipro, etc.)
- Clarithromycin (Biaxin, etc.)
- Erythromycin (E-Mycin, etc.)
- Fluconazole (Diflucan)
- Itraconazole (Sporanox, etc.)
- Ketoconazole (Nizoral, etc.)
- Posaconazole (Noxafil)
- Quinupristin (Synercid)
- Telithromycin (Ketek)
- Troleandomycin (TAO)
- Voriconazole (Vfend)
Comment:
Pimozide alone can prolong the QT interval, and it has been associated with ventricular arrhythmias (torsades de pointes). Drugs that inhibit CYP3A4 may increase pimozide serum concentrations.
Class 1: Avoid Combination
- Avoid: These antimicrobials should not be given to patients receiving pimozide due to the risk of life-threatening ventricular arrhythmias.
- Use Alternative:
- Azole Antifungals: Itraconazole and ketoconazole are potent inhibitors of CYP3A4; fluconazole appears weaker, but in larger doses it also inhibits CYP3A4. Terbinafine (Lamisil) does not appear to affect CYP3A4, and would not be expected to interact with pimozide.
- Macrolide Antibiotics: Unlike erythromycin, clarithromycin and troleandomycin, azithromycin (Zithromax) and dirithromycin* do not appear to inhibit CYP3A4. (*not available in US)
- Telithromycin: The use of azithromycin (Zithromax) or a quinolone antibiotic other than ciprofloxacin should be considered.