What the FDA labels say about taking them together
Phenytoin and vilazodone
Vilazodone's FDA label of May 22, 2024 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name vilazodone. The vilazodone label: “Based on clinical response, consider increasing the dosage of VIIBRYD, over 1 to 2 weeks in patients taking strong CYP3A4 inducers for greater than 14 days.”
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the vilazodone FDA label on DailyMed (effective May 22, 2024, Teva Pharmaceuticals, Inc.).
What does the phenytoin label say about vilazodone?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name vilazodone 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 vilazodone label say about phenytoin?
Vilazodone label, drug interactionsConcomitant Drug Name or Drug Class: Strong CYP3A4 Inducers (e.g., carbamazepine, phenytoin, rifampin); Clinical Rationale: The concomitant use of vilazodone hydrochloride and strong CYP3A4 inducers decreased the exposure of vilazodone compared to the use of vilazodone hydrochloride alone [see Clinical Pharmacology ()].; Clinical Recommendation: Based on clinical response, consider increasing the dosage of vilazodone hydrochloride, over 1 to 2 weeks in patients taking strong CYP3A4 inducers for greater than 14 days [see Dosage and Administration (), Clinical Pharmacology ()].
Source: FDA drug label (Viibryd, NDA022567), Allergan, Inc., effective October 1, 2023 (SPL set 4c55ccfb-c4cf-11df-851a-0800200c9a66), via openFDA
Source: FDA drug label (Vilazodone Hydrochloride), Teva Pharmaceuticals, Inc., effective May 22, 2024 (SPL set 3a4745a0-de23-4b40-923e-0d7dfe6b8634), 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 | Vilazodone | |
|---|---|---|
| Labeled for | Seizures and epilepsy | Depression |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.145 per capsule 100 mg capsule | $0.732 per tablet 10 mg 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