What the FDA labels say about taking them together
Ketoconazole and nefazodone
Nefazodone's FDA label of July 31, 2025 names ketoconazole in its warnings section; the ketoconazole label PlainMeds reads does not name nefazodone. The nefazodone label: “… the cytochrome P450 3A4 (CYP3A4) isozyme, and it has been demonstrated that ketoconazole, erythromycin, and other inhibitors of CYP3A4 can block the metabolism of these drugs, which can result in increased plasma …”
Check it at the source: the ketoconazole FDA label on DailyMed (effective January 28, 2026, E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC); the nefazodone FDA label on DailyMed (effective July 31, 2025, Teva Pharmaceuticals USA, Inc.).
What does the ketoconazole label say about nefazodone?
Ketoconazole's label (effective January 28, 2026) does not name nefazodone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (ketoconazole), E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC, effective January 28, 2026 (SPL set cad7c647-34a9-4e4e-83b3-8d78e58f588f), via openFDA; the full label on DailyMed
What does the nefazodone label say about ketoconazole?
Nefazodone label, warningsPotential Terfenadine, Astemizole, Cisapride, and Pimozide Interactions Terfenadine, astemizole, cisapride, and pimozide are all metabolized by the cytochrome P450 3A4 (CYP3A4) isozyme, and it has been demonstrated that ketoconazole, erythromycin, and other inhibitors of CYP3A4 can block the metabolism of these drugs, which can result in increased plasma concentrations of parent drug.
Source: FDA drug label (Nefazodone Hydrochloride), Teva Pharmaceuticals USA, Inc., effective July 31, 2025 (SPL set 51ff7db5-aaf9-4c3c-86e6-958ebf16b60f), 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
| Ketoconazole | Nefazodone | |
|---|---|---|
| Labeled for | Fungal infections | Depression |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.249 per gram 2% cream | $1.17 per tablet 100 mg tablet |
| Shortage now | No current entry | 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