What the FDA labels say about taking them together
Phenytoin and triamcinolone
Triamcinolone's FDA label (Triesence) of June 5, 2026 names phenytoin in its drug interactions section; phenytoin's label does not name triamcinolone itself but warns about its class (Corticosteroids). The triamcinolone label: “CYP 3A4 inducers; Drugs which induce hepatic microsomal drug metabolizing enzyme activity may enhance metabolism of corticosteroids and require that the dosage of corticosteroid be increased.”
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the triamcinolone FDA label on DailyMed (effective January 28, 2026, E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC).
What does the phenytoin label say about triamcinolone?
Phenytoin's label does not name triamcinolone 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
What does the triamcinolone label say about phenytoin?
Triesence label (Harrow Eye, LLC, June 5, 2026), drug interactionsCYP 3A4 inducers (e.g., barbiturates, phenytoin, carbamazepine, and rifampin): Drugs, such as barbiturates, phenytoin, ephedrine, and rifampin, which induce hepatic microsomal drug metabolizing enzyme activity may enhance metabolism of corticosteroid and require that the dosage of corticosteroid be increased.
Source: FDA drug label (Triesence, NDA022048), Harrow Eye, LLC, effective June 5, 2026 (SPL set 2267978c-72ad-9229-e063-6394a90a09d0), via openFDA
Source: FDA drug label (Zilretta, NDA208845), Pacira Pharmaceuticals, Inc., effective June 3, 2026 (SPL set cd5c4673-21f2-4126-9556-da847b3a228b), via openFDA
Source: FDA drug label (triamcinolone acetonide), E. Fougera & Co. a division of Fougera Pharmaceuticals, LLC, effective January 28, 2026 (SPL set 92a1ded0-8e1a-4994-9c8a-89e84fc85c94), 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
| Phenytoin | Triamcinolone | |
|---|---|---|
| Labeled for | Seizures and epilepsy | Asthma, Eczema (atopic dermatitis), Anemia, Leukemia, lymphoma and myeloma, Allergies, Fever, Pain, Osteoarthritis |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.145 per capsule 100 mg capsule | $0.0452 per gram 0.1% cream |
| Shortage now | No current entry | Listed; available |
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