What the FDA labels say about taking them together
Fosaprepitant and ketoconazole
Fosaprepitant's FDA label of July 29, 2026 names ketoconazole in its drug interactions section; the ketoconazole label PlainMeds reads does not name fosaprepitant. The fosaprepitant label: “Use of EMEND with strong or moderate CYP3A4 inhibitors may increase plasma concentrations of aprepitant and result in an increased risk of adverse reactions related to EMEND.”
Check it at the source: the fosaprepitant FDA label on DailyMed (effective July 29, 2026, AVYXA Pharma, LLC); the ketoconazole FDA label on DailyMed (effective January 28, 2026, E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC).
What does the fosaprepitant label say about ketoconazole?
Fosaprepitant label, drug interactionsExamples; Moderate inhibitor: diltiazem Strong inhibitors: ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir
Fosaprepitant label, warnings and precautionsUse of NAVITRUX with strong or moderate CYP3A4 inhibitors (e.g., ketoconazole, diltiazem) may increase plasma concentrations of aprepitant and result in an increased risk of adverse reactions related to NAVITRUX.
Source: FDA drug label (Emend, NDA022023), Merck Sharp & Dohme LLC, effective February 20, 2026 (SPL set 8d66803a-6811-4c29-9c57-e16acfa87f21), via openFDA
Source: FDA drug label (Focinvez, NDA216686), Steriscience Specialties Private Limited, effective March 30, 2026 (SPL set 18a60093-cec8-1b8c-e063-6394a90a8902), via openFDA
Source: FDA drug label (NAVITRUX), AVYXA Pharma, LLC, effective July 29, 2026 (SPL set a41b7c3a-1376-43a7-b5b9-6ba2eba1e169), via openFDA; the full label on DailyMed
What does the ketoconazole label say about fosaprepitant?
Ketoconazole's label (effective January 28, 2026) does not name fosaprepitant 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
| Fosaprepitant | Ketoconazole | |
|---|---|---|
| Labeled for | n/a | Fungal infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $0.249 per gram 2% cream |
| 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