Fidaxomicin and Pimozide interaction
Fidaxomicin and Pimozide: the Pimozide prescribing label flags this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Pimozide label · effective 2026-08-12
Ventricular arrhythmias have been rarely associated with the use of macrolide antibiotics in patients with prolonged QT intervals, as might be produced by pimozide.
Macrolide antibiotics are inhibitors of CYP 3A4, and thus could potentially impede pimozide metabolism.
For these reasons, pimozide is contraindicated in patients receiving the macrolide antibiotics clarithromycin, erythromycin, azithromycin, dirithromycin, and troleandomycin.
Also, the use of macrolide antibiotics in patients with prolonged QT intervals has been rarely associated with ventricular arrhythmias.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.