What the FDA labels say about taking them together
Erythromycin and nefazodone
Nefazodone's FDA label of July 31, 2025 names erythromycin in its warnings section; the erythromycin labels PlainMeds reads (4) do not name nefazodone. The nefazodone label: “… 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 …”
Check it at the source: the erythromycin FDA label on DailyMed (effective August 1, 2024, Teva Pharmaceuticals USA, Inc.); the nefazodone FDA label on DailyMed (effective July 31, 2025, Teva Pharmaceuticals USA, Inc.).
What does the erythromycin label say about nefazodone?
Erythromycin's label (effective August 1, 2024) and its 3 other brand-application labels do 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 (Erythromycin), Teva Pharmaceuticals USA, Inc., effective August 1, 2024 (SPL set 75a0bd5a-d09f-483b-bfd8-f8343b149eb2), via openFDA; the full label on DailyMed
What does the nefazodone label say about erythromycin?
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
| Erythromycin | Nefazodone | |
|---|---|---|
| Labeled for | Bacterial infections, Acne | Depression |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.96 per tablet 250 mg tablet | $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