What the FDA labels say about taking them together
Phenytoin and selegiline
Selegiline's FDA label (Zelapar) of June 1, 2021 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name selegiline.
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the selegiline FDA label on DailyMed (effective August 7, 2024, Rising Pharma Holdings, Inc.).
What does the phenytoin label say about selegiline?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name selegiline 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 selegiline label say about phenytoin?
Zelapar label (Bausch Health US, LLC, June 1, 2021), drug interactionsDrugs that induce CYP3A4 (e.g., phenytoin, carbamazepine, nafcillin, phenobarbital, and rifampin) should be used with caution.
Source: FDA drug label (Zelapar, NDA021479), Bausch Health US, LLC, effective June 1, 2021 (SPL set 380d7717-2a79-42f3-a712-efe5e7696ba0), via openFDA
Source: FDA drug label (Selegiline Hydrochloride), Rising Pharma Holdings, Inc., effective August 7, 2024 (SPL set 23c4481f-d150-40c6-addb-b3e454ca914f), 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 | Selegiline | |
|---|---|---|
| Labeled for | Seizures and epilepsy | Parkinson's disease, Depression |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.145 per capsule 100 mg capsule | $0.756 per capsule 5 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