What the FDA labels say about taking them together
Disulfiram and isoniazid
Disulfiram's FDA label of August 20, 2024 names isoniazid in its drug interactions section; the isoniazid label PlainMeds reads does not name disulfiram.
Check it at the source: the disulfiram FDA label on DailyMed (effective August 20, 2024, Sigmapharm Laboratories, LLC); the isoniazid FDA label on DailyMed (effective July 8, 2025, OMNIVIUM PHARMACEUTICALS LLC.).
What does the disulfiram label say about isoniazid?
Disulfiram label, drug interactionsPatients taking isoniazid when disulfiram is given should be observed for the appearance of unsteady gait or marked changes in mental status, the disulfiram should be discontinued if such signs appear.
Source: FDA drug label (Disulfiram), Sigmapharm Laboratories, LLC, effective August 20, 2024 (SPL set 40f5497f-fe84-43b2-8ff4-32d59edf3917), via openFDA; the full label on DailyMed
What does the isoniazid label say about disulfiram?
Isoniazid's label (effective July 8, 2025) does not name disulfiram in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (isoniazid), OMNIVIUM PHARMACEUTICALS LLC., effective July 8, 2025 (SPL set 35400f1d-fd25-4bfa-a382-ac390e21bf2e), 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
| Disulfiram | Isoniazid | |
|---|---|---|
| Labeled for | Alcohol use disorder | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $1.82 per tablet 250 mg tablet | $3.40 per tablet 300 mg tablet |
| 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