What the FDA labels say about taking them together
Posaconazole and quinidine
Posaconazole's FDA label of August 3, 2026 names quinidine in its contraindications section; the quinidine label PlainMeds reads does not name posaconazole. The posaconazole label: “Noxafil increases concentrations and toxicities of: Sirolimus CYP3A4 substrates (pimozide, quinidine): can result in QTc interval prolongation and cases of torsades de pointes (TdP) HMG-CoA Reductase Inhibitors …”
Check it at the source: the posaconazole FDA label on DailyMed (effective August 3, 2026, Aurobindo Pharma Limited); the quinidine FDA label on DailyMed (effective February 1, 2018, Sun Pharmaceutical Industries, Inc.).
What does the posaconazole label say about quinidine?
Posaconazole label, contraindicationsSirolimus ( 4.2 , 7.2 ) CYP3A4 substrates (pimozide, quinidine): can result in QTc interval prolongation and cases of torsades de pointes (TdP) ( 4.3 , 5.2 , 7.2 ) HMG-CoA Reductase Inhibitors Primarily Metabolized through CYP3A4 ( 4.4 , 7.2 ) Ergot alkaloids ( 4.5 , 7.2 ) Venetoclax:
Posaconazole label, drug interactionsMechanism 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 ].
Source: FDA drug label (Noxafil, NDA022003), Merck Sharp & Dohme LLC, effective February 13, 2026 (SPL set b073b082-7b57-4423-8c06-4fd4263d6f84), via openFDA
Source: FDA drug label (POSACONAZOLE), Aurobindo Pharma Limited, effective August 3, 2026 (SPL set f8a26673-261c-4e8e-b1e1-9e23aaf7f285), via openFDA; the full label on DailyMed
What does the quinidine label say about posaconazole?
Quinidine's label (effective February 1, 2018) does not name posaconazole in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Quinidine Gluconate), Sun Pharmaceutical Industries, Inc., effective February 1, 2018 (SPL set 5023f053-fcc4-4c2c-aa59-9ec198ad185e), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Posaconazole | Quinidine | |
|---|---|---|
| Labeled for | Fungal infections | Atrial fibrillation |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $2.03 per tablet 100 mg tablet | $4.92 per tablet 324 mg tablet |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once