Posaconazole and Thioridazine interaction
Posaconazole and Thioridazine: 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 Thioridazine (Thioridazine Hydrochloride) label · effective 2026-03-02
CONTRAINDICATIONS Thioridazine hydrochloride tablet use should be avoided in combination with other drugs that are known to prolong the QTc interval and in patients with congenital long QT syndrome or a history of cardiac arrhythmias.
Such an increased risk may result also from the additive effect of coadministering thioridazine with other agents that prolong the QTc interval.
From the Posaconazole (NOXAFIL) label · effective 2026-02-13
Concomitant Use with Midazolam : Noxafil can prolong hypnotic/sedative effects.
Increased plasma midazolam concentrations could potentiate and prolong hypnotic and sedative effects.
Benzodiazepines that are CYP3A4 Substrates Mechanism and Clinical Effect(s) Concomitant use of posaconazole with midazolam increased midazolam plasma concentrations which could potentiate and prolong hypnotic and sedative effects [see Clinical Pharmacology (12.3) ] .
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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.