What the FDA labels say about taking them together
Isoflurane and nitrous oxide
Isoflurane's FDA label of January 5, 2026 names nitrous oxide in its drug interactions section; the nitrous oxide labels PlainMeds reads (4) do not name isoflurane. The isoflurane label: “Nitrous oxide decreases the MAC of FORANE.”
Check it at the source: the isoflurane FDA label on DailyMed (effective January 5, 2026, Shandong New Time Pharmaceutical Co., Ltd.); the nitrous oxide FDA label on DailyMed (effective December 2, 2025, Machine & Welding Supply Company dba Arc3 Gases South).
What does the isoflurane label say about nitrous oxide?
Isoflurane label, drug interactionsNitrous oxide decreases the MAC of isoflurane [see Dosage and Administration (2.1)].
Source: FDA drug label (Forane, NDA017624), Baxter Healthcare Corporation, effective December 9, 2024 (SPL set 3d30eb8d-a62e-475f-926b-78ba63bee9c8), via openFDA
Source: FDA drug label (Isoflurane), Shandong New Time Pharmaceutical Co., Ltd., effective January 5, 2026 (SPL set 662ceaf6-650b-4dea-bbee-652f46426024), via openFDA; the full label on DailyMed
What does the nitrous oxide label say about isoflurane?
Nitrous oxide's label (effective December 2, 2025) and its 3 other brand-application labels do not name isoflurane in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Nitrous Oxide), Machine & Welding Supply Company dba Arc3 Gases South, effective December 2, 2025 (SPL set a5070767-c36a-4131-aa09-1bccfa24aa71), 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
| Isoflurane | Nitrous oxide | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | No |
| 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