What the FDA labels say about taking them together
Diltiazem and fosaprepitant
Fosaprepitant's FDA label of July 29, 2026 names diltiazem in its drug interactions section; the diltiazem labels PlainMeds reads (4) do 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 diltiazem FDA label on DailyMed (effective August 7, 2026, Bausch Health US, LLC); the fosaprepitant FDA label on DailyMed (effective July 29, 2026, AVYXA Pharma, LLC).
What does the diltiazem label say about fosaprepitant?
Diltiazem's label (effective August 7, 2026) and its 3 other brand-application labels do 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 (TIAZAC EXTENDED RELEASE), Bausch Health US, LLC, effective August 7, 2026 (SPL set c567fe7e-887e-4291-a0d1-2dd3f25cbf25), via openFDA; the full label on DailyMed
What does the fosaprepitant label say about diltiazem?
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
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
| Diltiazem | Fosaprepitant | |
|---|---|---|
| Labeled for | High blood pressure, Angina, Atrial fibrillation | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.144 per capsule 24h ER(cd) 120 mg capsule | n/a |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
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