What the FDA labels say about taking them together
Isoniazid and rifapentine
Rifapentine's FDA label of February 6, 2026 names isoniazid in its warnings and precautions section; the isoniazid label PlainMeds reads does not name rifapentine. The rifapentine label: “Do not use as a once-weekly continuation phase regimen with isoniazid in HIV-infected patients.”
Check it at the source: the isoniazid FDA label on DailyMed (effective July 8, 2025, OMNIVIUM PHARMACEUTICALS LLC.); the rifapentine FDA label on DailyMed (effective February 6, 2026, sanofi-aventis U.S. LLC).
What does the isoniazid label say about rifapentine?
Isoniazid's label (effective July 8, 2025) does not name rifapentine 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
What does the rifapentine label say about isoniazid?
Rifapentine label, warnings and precautionsDo not use as a once-weekly continuation phase regimen with isoniazid in HIV-infected patients.
Source: FDA drug label (Priftin), sanofi-aventis U.S. LLC, effective February 6, 2026 (SPL set 3a64fb70-b85e-43d9-8bcd-7e893f568ae1), 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
| Isoniazid | Rifapentine | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $3.40 per tablet 300 mg tablet | $4.83 per tablet 150 mg tablet |
| Shortage now | No current entry | Resolved |
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