Isoniazid and Disulfiram: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Isoniazid
No brand names on recordDisulfiram
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased risk of disulfiram CNS effects (changes in behavior, coordination, and mood)
Interaction Deep Dive
Concomitant use of isoniazid and disulfiram may exaggerate the CNS effects of disulfiram (acute behavioral and coordination changes)1. Monitor patients for the appearance of unsteady gait or marked changes in mental status, the disulfiram should be discontinued if such signs appear 2. Concomitant isoniazid and disulfiram therapy has resulted in coordination difficulty plus changes in affect and behavior, but additional drugs were involved and a clear relationship was not established. The mechanism of this interaction may involve inhibition of DOPamine metabolic pathways 3.
Why it happens (mechanism)
Inhibition of dopamine metabolic pathways
Literature reports
1 report — tap to read
a) Seven alcoholic tubercular patients received isoniazid and chlordiazePOXIDE without incurring any adverse effects. After the addition of disulfiram, mental status changes (confusion, paranoia, irritability) and coordination changes (difficulty walking, overreaching) developed. The authors hypothesized that isoniazid and disulfiram inhibited two DOPamine metabolic pathways which may have increased activity of the remaining pathway, raising the amount of methylated DOPamine products 3.
Common questions
Can I take Isoniazid and Disulfiram together?
Increased risk of disulfiram CNS effects (changes in behavior, coordination, and mood) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Isoniazid and Disulfiram interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Isoniazid or Disulfiram need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (3)
- Product Information: RIFATER(R) oral tablets, rifampin, isoniazid, pyrazinamide oral tablets. sanofi-aventis US LLC (per FDA), Bridgewater, NJ, 2023. DailyMed
- Product Information: Antabuse(R) oral tablets, disulfiram oral tablets. Duramed Pharmaceuticals, Inc. (per DailyMed), Pomona, NY, 2010. DailyMed
- Whittington HG & Grey L: Possible interaction between disulfiram and isoniazid. Am J Psychiatry 1969; 125:1725-1729. PubMed
Keep reading about Isoniazid
Keep reading about Disulfiram
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist