What the FDA labels say about taking them together
Fosaprepitant and rifampin
Fosaprepitant's FDA label of July 29, 2026 names rifampin in its drug interactions section; the rifampin label PlainMeds reads does not name fosaprepitant. The fosaprepitant label: “Use of EMEND with strong CYP3A4 inducers (e.g., rifampin) may result in a reduction in aprepitant plasma concentrations and decreased efficacy of EMEND.”
Check it at the source: the fosaprepitant FDA label on DailyMed (effective July 29, 2026, AVYXA Pharma, LLC); the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.).
What does the fosaprepitant label say about rifampin?
Fosaprepitant label, drug interactionsExamples; rifampin, carbamazepine, phenytoin
Fosaprepitant label, warnings and precautionsUse of NAVITRUX with strong CYP3A4 inducers (e.g., rifampin) may result in a reduction in aprepitant plasma concentrations and decreased efficacy of 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 rifampin label say about fosaprepitant?
Rifampin's label (effective February 11, 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 (rifampin), Lupin Pharmaceuticals, Inc., effective February 11, 2026 (SPL set b56004f0-f23d-47f6-80c7-39884fccbccc), 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 | Rifampin | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $0.679 per capsule 300 mg capsule |
| Shortage now | A presentation being discontinued | In shortage |
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