What the FDA labels say about taking them together
Efavirenz and ketoconazole
Efavirenz's FDA label of March 31, 2024 names ketoconazole in its drug interactions section; the ketoconazole label PlainMeds reads does not name efavirenz. The efavirenz label: “… Consider alternative antifungal treatment because no dose recommendation for ketoconazole can be made. Avoid concomitant use unless the benefit outweighs the risks.”
Check it at the source: the efavirenz FDA label on DailyMed (effective March 31, 2024, Cipla USA Inc.); the ketoconazole FDA label on DailyMed (effective January 28, 2026, E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC).
What does the efavirenz label say about ketoconazole?
Efavirenz label, drug interactionsConcomitant Drug Class/Drug Name: Antifungals: Voriconazole Itraconazole Ketoconazole Posaconazole; Effect: ↓ voriconazole * ↑ efavirenz * ↓ itraconazole * ↓ hydroxy itraconazole * ↓ ketoconazole ↓ posaconazole *; Clinical Comment: Efavirenz and voriconazole should not be coadministered at standard doses. When voriconazole is coadministered with efavirenz, voriconazole maintenance dose should be increased to 400 mg every 12 hours and efavirenz dose should be decreased to 300 mg once daily using the capsule formulation. Efavirenz tablets must not be broken. [see Dosage and Administration () and Clinical Pharmacology (, and)]. …
Source: FDA drug label (Efavirenz), Cipla USA Inc., effective March 31, 2024 (SPL set 92603fa5-7a2c-4bfb-9a70-aadb4fba952c), via openFDA; the full label on DailyMed
What does the ketoconazole label say about efavirenz?
Ketoconazole's label (effective January 28, 2026) does not name efavirenz 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
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
| Efavirenz | Ketoconazole | |
|---|---|---|
| Labeled for | HIV | Fungal infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.28 per tablet 600 mg tablet | $0.249 per gram 2% cream |
| 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