What the FDA labels say about taking them together
Fludrocortisone and phenytoin
Fludrocortisone's FDA label of October 29, 2024 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name fludrocortisone. The fludrocortisone label: “Barbiturates, phenytoin, or rifampin –increased metabolic clearance of fludrocortisone acetate because of the induction of hepatic enzymes.”
Check it at the source: the fludrocortisone FDA label on DailyMed (effective October 29, 2024, Zydus Lifesciences Limited); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the fludrocortisone label say about phenytoin?
Fludrocortisone label, drug interactionsBarbiturates, phenytoin, or rifampin –increased metabolic clearance of fludrocortisone acetate because of the induction of hepatic enzymes.
Source: FDA drug label (Fludrocortisone acetate), Zydus Lifesciences Limited, effective October 29, 2024 (SPL set 6c4a7d2d-00a4-4d80-ab4c-2afd4e4f614e), via openFDA; the full label on DailyMed
What does the phenytoin label say about fludrocortisone?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name fludrocortisone in these sections. A label lists what its studies and reports found; it is not a complete list.
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
| Fludrocortisone | Phenytoin | |
|---|---|---|
| Labeled for | n/a | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.311 per tablet 0.1 mg tablet | $0.145 per capsule 100 mg capsule |
| Shortage now | No current entry | 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