What the FDA labels say about taking them together
Methylprednisolone and phenytoin
Methylprednisolone's FDA label of June 22, 2026 names phenytoin in its drug interactions section; phenytoin's label does not name methylprednisolone itself but warns about its class (Corticosteroids). The methylprednisolone label: “Hepatic Enzyme Inducers: Drugs which induce cytochrome P450 3A4 enzyme activity may enhance the metabolism of corticosteroids and require that the dosage of the corticosteroid be increased.”
Check it at the source: the methylprednisolone FDA label on DailyMed (effective June 22, 2026, Mylan Pharmaceuticals Inc.); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the methylprednisolone label say about phenytoin?
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.
Solu-Medrol label (Pharmacia & Upjohn Company LLC, December 2, 2025), drug interactionsHepatic Enzyme Inducers (e.g., barbiturates, phenytoin, carbamazepine, rifampin): Drugs which induce cytochrome P450 3A4 enzyme activity may enhance the metabolism of corticosteroids and require that the dosage of the corticosteroid be increased.
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
What does the phenytoin label say about methylprednisolone?
Phenytoin's label does not name methylprednisolone itself; it warns about its class (Corticosteroids):
Phenytoin label, drug interactionsWarfarin Increased and decreased PT/INR responses have been reported when phenytoin is coadministered with warfarin Other Corticosteroids, doxycycline, estrogens, furosemide, oral contraceptives, paroxetine, quinidine, rifampin, sertraline, theophylline, and vitamin D Drugs whose level is decreased by phenytoin Anticoagulants Apixaban, dabigatran, edoxaban, rivaroxaban Antiepileptic drugs The effect of phenytoin on phenobarbital, valproic acid and sodium valproate serum levels is unpredictable Carbamazepine …
Source: FDA drug label (Phenytek), Mylan Pharmaceuticals Inc., effective October 15, 2024 (SPL set 0f94c791-8b07-4b41-927e-c9f28bec5f60), 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 | Phenytoin | |
|---|---|---|
| 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 | $0.145 per capsule 100 mg capsule |
| Shortage now | In shortage | 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