Fluvoxamine and Pimozide interaction
Fluvoxamine and Pimozide: both prescribing labels flag 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 Fluvoxamine (fluvoxamine maleate) label · effective 2026-04-23
Coadministration Coadministration of tizanidine, thioridazine, alosetron, or pimozide with Fluvoxamine Maleate Tablets is contraindicated [see Warnings and Precautions ( 5.4 , 5.5 , 5.6 , 5.7 )] .
Coadministration of tizanidine, thioridazine, alosteron, pimozide ( 4 )
An increased plasma concentration of pimozide causes QT prolongation and has been associated with torsades de pointes-type ventricular tachycardia, sometimes fatal.
Potential Pimozide Interaction Pimozide is metabolized by the cytochrome P4503A4 isoenzyme, and it has been demonstrated that ketoconazole, a potent inhibitor of CYP3A4, blocks the metabolism of this drug, resulting in increased plasma concentrations of parent drug.
Pimozide: See Contraindications ( 4 ), Warnings and Precautions ( 5.6 ) .
From the Pimozide label · effective 2026-08-12
Other drugs that are relatively less potent inhibitors of CYP 3A4 should also be avoided, in view of the risks: e.g., zileuton, fluvoxamine.
DRUG INTERACTIONS Because pimozide prolongs the QT interval of the electrocardiogram, an additive effect on QT interval would be anticipated if administered with other drugs, such as phenothiazines, tricyclic antidepressants or antiarrhythmic agents, which prolong the QT interval.
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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.