What the FDA labels say about taking them together
Ketoconazole and terbinafine
Terbinafine's FDA label of October 17, 2025 names ketoconazole in its drug interactions section; the ketoconazole label PlainMeds reads does not name terbinafine. The terbinafine label: “Based on this finding, it is likely that other inhibitors of both CYP2C9 and CYP3A4 may also lead to a substantial increase in the systemic exposure (C max and AUC) of terbinafine when concomitantly administered.”
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 terbinafine FDA label on DailyMed (effective October 17, 2025, PD-Rx Pharmaceuticals, Inc.).
What does the ketoconazole label say about terbinafine?
Ketoconazole's label (effective January 28, 2026) does not name terbinafine 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 terbinafine label say about ketoconazole?
Terbinafine label, drug interactionsBased on this finding, it is likely that other inhibitors of both CYP2C9 and CYP3A4 (e.g., ketoconazole, amiodarone) may also lead to a substantial increase in the systemic exposure (C max and AUC) of terbinafine when concomitantly administered.
Source: FDA drug label (Terbinafine Hydrochloride), PD-Rx Pharmaceuticals, Inc., effective October 17, 2025 (SPL set 2df111dc-ecac-4161-9e22-38436eb37c1f), 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 | Terbinafine | |
|---|---|---|
| Labeled for | Fungal infections | Fungal infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.249 per gram 2% cream | $0.143 per tablet 250 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