What the FDA labels say about taking them together
Phenytoin and roflumilast
Roflumilast's FDA label of March 12, 2020 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name roflumilast. The roflumilast label: “Therefore the use of strong cytochrome P450 inducers with DALIRESP is not recommended.”
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the roflumilast FDA label on DailyMed (effective March 12, 2020, AstraZeneca Pharmaceuticals LP).
What does the phenytoin label say about roflumilast?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name roflumilast 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
What does the roflumilast label say about phenytoin?
Roflumilast label, drug interactionsTherefore the use of strong cytochrome P450 inducers (e.g., rifampicin, phenobarbital, carbamazepine, and phenytoin) with DALIRESP is not recommended [see Warnings and Precautions (5.4) and Clinical Pharmacology (12.3) ].
Roflumilast label, warnings and precautionsDrug Interactions: Use with strong cytochrome P450 enzyme inducers (e.g., rifampicin, phenobarbital, carbamazepine, phenytoin) is not recommended.
Source: FDA drug label (Daliresp), AstraZeneca Pharmaceuticals LP, effective March 12, 2020 (SPL set c9a1d0a8-581f-4f91-a2b8-f419192d0ebf), 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 | Roflumilast | |
|---|---|---|
| Labeled for | Seizures and epilepsy | COPD, Psoriasis, Eczema (atopic dermatitis) |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.145 per capsule 100 mg capsule | $0.311 per tablet 500 mcg tablet |
| 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