What the FDA labels say about taking them together
Isoniazid and methylprednisolone
Methylprednisolone's FDA label (Solu-Medrol) of December 2, 2025 names isoniazid in its drug interactions section; the isoniazid label PlainMeds reads does not name methylprednisolone. The methylprednisolone label: “Antitubercular drugs: Serum concentrations of isoniazid may be decreased.”
Check it at the source: the isoniazid FDA label on DailyMed (effective July 8, 2025, OMNIVIUM PHARMACEUTICALS LLC.); the methylprednisolone FDA label on DailyMed (effective June 22, 2026, Mylan Pharmaceuticals Inc.).
What does the isoniazid label say about methylprednisolone?
Isoniazid's label (effective July 8, 2025) does not name methylprednisolone 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 methylprednisolone label say about isoniazid?
Solu-Medrol label (Pharmacia & Upjohn Company LLC, December 2, 2025), drug interactionsAntitubercular drugs: Serum concentrations of isoniazid may be decreased.
Source: FDA drug label (Solu-Medrol, NDA011856), Pharmacia & Upjohn Company LLC, effective December 2, 2025 (SPL set cd99be87-c8d9-48d6-a8e5-e081052e3f19), via openFDA
Source: FDA drug label (Methylprednisolone), NDA011153 (Pfizer), as published by Mylan Pharmaceuticals Inc., effective June 22, 2026 (SPL set 22dd75d6-f89a-44f7-8ca6-b64c4e9806dd), 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 | Methylprednisolone | |
|---|---|---|
| Labeled for | n/a | Osteoarthritis, Allergies, Herpes and shingles, Leukemia, lymphoma and myeloma, Crohn's disease and ulcerative colitis, Multiple sclerosis, Asthma, Eczema (atopic dermatitis), Anemia |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $3.40 per tablet 300 mg tablet | $0.121 per tablet 4 mg tablet |
| Shortage now | No current entry | In shortage |
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