Pimozide and Posaconazole interaction
Pimozide and Posaconazole: 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 Posaconazole (NOXAFIL) label · effective 2026-02-13
CYP3A4 substrates (pimozide, quinidine): can result in QTc interval prolongation and cases of torsades de pointes (TdP) ( 4.3 , 5.2 , 7.2 )
Concomitant administration of Noxafil with the CYP3A4 substrates, pimozide and quinidine may result in increased plasma concentrations of these drugs, leading to QTc prolongation and cases of torsades de pointes [see Warnings and Precautions (5.2) and Drug Interactions (7.2) ] .
CYP3A4 Substrates that Prolong QTc Interval Mechanism and Clinical Effect(s) Concomitant use of posaconazole with CYP3A4 substrates such as pimozide and quinidine may result in increased plasma concentrations of the CYP3A4 substrates leading to QTc interval prolongation and torsades de pointes [see Warnings and Precautions (5.2) ].
Prevention or Management Pimozide Concomitant use with posaconazole is contraindicated.
Concomitant Use with Midazolam : Noxafil can prolong hypnotic/sedative effects.
From the Pimozide label · effective 2026-08-12
Because pimozide prolongs the QT interval of the electrocardiogram it is contraindicated in patients with congenital long QT syndrome, patients with a history of cardiac arrhythmias, patients taking other drugs which prolong the QT interval of the electrocardiogram or patients with known hypokalemia or hypomagnesemia (see also PRECAUTIONS - DRUG INTERACTIONS ).
Because azole antifungal agents are also inhibitors of the CYP 3A4 enzymes and thus may likewise impair pimozide metabolism, pimozide is contraindicated in patients receiving the azole antifungal agents itraconazole and ketoconazole.
Since pimozide is partly metabolized via CYP 3A4, it should not be administered concomitantly with inhibitors of this metabolic system, such as azole antifungal agents and protease inhibitor drugs (see CONTRAINDICATIONS ).
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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.