What the FDA labels say about taking them together
Cidofovir and foscarnet
Cidofovir's FDA label of October 25, 2023 names foscarnet in its drug interactions section; the foscarnet label PlainMeds reads does not name cidofovir. The cidofovir label: “Nephrotoxic agents Concomitant administration of cidofovir injection and agents with nephrotoxic potential [e.g., intravenous aminoglycosides, amphotericin B, foscarnet, intravenous pentamidine, vancomycin, and …”
Check it at the source: the cidofovir FDA label on DailyMed (effective October 25, 2023, Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.); the foscarnet FDA label on DailyMed (effective December 11, 2025, Clinigen Limited).
What does the cidofovir label say about foscarnet?
Cidofovir label, drug interactionsNephrotoxic agents Concomitant administration of cidofovir injection and agents with nephrotoxic potential [e.g., intravenous aminoglycosides (e.g., tobramycin, gentamicin, and amikacin), amphotericin B, foscarnet, intravenous pentamidine, vancomycin, and nonsteroidal anti-inflammatory agents] is contraindicated.
Cidofovir label, warningsThe safety of cidofovir injection has not been evaluated in patients receiving other known potentially nephrotoxic agents, such as intravenous aminoglycosides (e.g., tobramycin, gentamicin, and amikacin), amphotericin B, foscarnet, intravenous pentamidine, vancomycin, and non-steroidal anti-inflammatory agents (see DOSAGE AND ADMINISTRATION ).
Source: FDA drug label (CIDOFOVIR DIHYDRATE), Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc., effective October 25, 2023 (SPL set 44966a7e-d777-40fb-956f-d0f31f737848), via openFDA; the full label on DailyMed
What does the foscarnet label say about cidofovir?
Foscarnet's label (effective December 11, 2025) does not name cidofovir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Foscavir), Clinigen Limited, effective December 11, 2025 (SPL set 90e3da4e-3b1f-428b-99ca-e4bed1c80028), 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
| Cidofovir | Foscarnet | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | n/a |
| 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