What the FDA labels say about taking them together
Isoniazid and multiple vitamins
Multiple vitamins's FDA label of November 20, 2024 names isoniazid in its drug interactions section; the isoniazid label PlainMeds reads does not name multiple vitamins. The multiple vitamins label: “Hydralazine, Isoniazid: Concomitant administration of hydralazine or isoniazid may increase pyridoxine requirements.”
Check it at the source: the isoniazid FDA label on DailyMed (effective July 8, 2025, OMNIVIUM PHARMACEUTICALS LLC.); the multiple vitamins FDA label on DailyMed (effective November 20, 2024).
What does the isoniazid label say about multiple vitamins?
Isoniazid's label (effective July 8, 2025) does not name multiple vitamins 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 multiple vitamins label say about isoniazid?
Multiple vitamins label, drug interactionsHydralazine, Isoniazid: Concomitant administration of hydralazine or isoniazid may increase pyridoxine requirements ( 7.2 ).
Source: FDA drug label (Infuvite Pediatric), Sandoz Inc, effective November 20, 2024 (SPL set 6d06546e-8b0a-4490-82d9-397bd902a044), 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 | Multiple vitamins | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $3.40 per tablet 300 mg tablet | 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