What the FDA labels say about taking them together
Hydrocortisone and phenytoin
Hydrocortisone's FDA label (Solu-Cortef) of August 27, 2026 names phenytoin in its drug interactions section; phenytoin's label does not name hydrocortisone itself but warns about its class (Corticosteroids). The hydrocortisone label: “Hydrocortisone is metabolized by cytochrome P450 3A4 (CYP3A4). Concomitant administration of inducers of CYP3A4 may lead to decreases in serum concentrations of ALKINDI SPRINKLE and increase the risk of adverse …”
Check it at the source: the hydrocortisone FDA label on DailyMed (effective August 19, 2026); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the hydrocortisone label say about phenytoin?
Solu-Cortef label (Pharmacia & Upjohn Company LLC, August 27, 2026), drug interactionsHepatic Enzyme Inducers (e.g., barbiturates, phenytoin, carbamazepine, rifampin): Drugs that induce cytochrome P450 3A4 enzyme activity may enhance the metabolism of corticosteroids and require that the dosage of the corticosteroid be increased.
Alkindi Sprinkle label (Eton Pharmaceuticals, Inc., April 21, 2026), drug interactionsClinical Impact: Hydrocortisone is metabolized by cytochrome P450 3A4 (CYP3A4). Concomitant administration of inducers of CYP3A4 may lead to decreases in serum concentrations of ALKINDI SPRINKLE and increase the risk of adverse reactions, including adrenal crisis. Intervention: Concomitant use of CYP3A4 inducers may require an increase in the ALKINDI SPRINKLE dose. Anticonvulsants: phenytoin, carbamazepine and oxcarbazepine Antibiotics: rifampicin and rifabutin Barbiturates: phenobarbital and primidone Antiretrovirals: efavirenz and nevirapine Estrogen and Estrogen …
Source: FDA drug label (Solu-Cortef, NDA009866), Pharmacia & Upjohn Company LLC, effective August 27, 2026 (SPL set 65eefd58-b166-4d71-ade6-45c8fdf86922), via openFDA
Source: FDA drug label (Alkindi Sprinkle, NDA213876), Eton Pharmaceuticals, Inc., effective April 21, 2026 (SPL set 26c13a5f-7119-4c6a-bf10-fda4e07d7682), via openFDA
Source: FDA drug label (hydrocortisone 1), Kroger Company, effective August 19, 2026 (SPL set f05edff2-2dc5-427c-b52c-518e0aaef4e0), via openFDA; the full label on DailyMed
What does the phenytoin label say about hydrocortisone?
Phenytoin's label does not name hydrocortisone 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
| Hydrocortisone | Phenytoin | |
|---|---|---|
| Labeled for | Osteoarthritis, Asthma, Allergies, Herpes and shingles, Leukemia, lymphoma and myeloma, Crohn's disease and ulcerative colitis, Eczema (atopic dermatitis) | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.0613 per gram 1% cream | $0.145 per capsule 100 mg capsule |
| Shortage now | A presentation being discontinued | 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