What the FDA labels say about taking them together
Methylprednisolone and phenobarbital
Methylprednisolone's FDA label of June 22, 2026 names phenobarbital in its drug interactions section; the phenobarbital labels PlainMeds reads (2) do not name methylprednisolone. The methylprednisolone label: “Drugs that induce hepatic enzymes such as phenobarbital, phenytoin, and rifampin may increase the clearance of methylprednisolone and may require increases in methylprednisolone dose to achieve the desired response.”
Check it at the source: the methylprednisolone FDA label on DailyMed (effective June 22, 2026, Mylan Pharmaceuticals Inc.); the phenobarbital FDA label on DailyMed (effective August 27, 2026).
What does the methylprednisolone label say about phenobarbital?
Methylprednisolone label, drug interactionsDrugs that induce hepatic enzymes such as phenobarbital, phenytoin, and rifampin may increase the clearance of methylprednisolone and may require increases in methylprednisolone dose to achieve the desired response.
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
What does the phenobarbital label say about methylprednisolone?
Phenobarbital's label (effective August 27, 2026) and its 1 other brand-application label do 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 (Phenobarbital), Chartwell RX, LLC, effective August 27, 2026 (SPL set 74428144-fb24-40a5-a670-3b876e2d116c), 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
| Methylprednisolone | Phenobarbital | |
|---|---|---|
| Labeled for | Osteoarthritis, Allergies, Herpes and shingles, Leukemia, lymphoma and myeloma, Crohn's disease and ulcerative colitis, Multiple sclerosis, Asthma, Eczema (atopic dermatitis), Anemia | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.121 per tablet 4 mg tablet | $0.213 per tablet 100 mg tablet |
| Shortage now | In shortage | A presentation being discontinued |
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