What the FDA labels say about taking them together
Nilutamide and phenytoin
Nilutamide's FDA label of June 26, 2026 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name nilutamide. The nilutamide label: “Consequently, drugs with a low therapeutic margin, such as vitamin K antagonists, phenytoin, and theophylline, could have a delayed elimination and increases in their serum half-life leading to a toxic level.”
Check it at the source: the nilutamide FDA label on DailyMed (effective June 26, 2026, ANI Pharmaceuticals, Inc.); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the nilutamide label say about phenytoin?
Nilutamide label, drug interactionsConsequently, drugs with a low therapeutic margin, such as vitamin K antagonists, phenytoin, and theophylline, could have a delayed elimination and increases in their serum half-life leading to a toxic level.
Source: FDA drug label (Nilutamide), ANDA207631 (Ani Pharms), as published by ANI Pharmaceuticals, Inc., effective June 26, 2026 (SPL set d5740b8f-fbb3-4023-9133-9e359a9ab980), via openFDA; the full label on DailyMed
What does the phenytoin label say about nilutamide?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name nilutamide 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
| Nilutamide | Phenytoin | |
|---|---|---|
| Labeled for | Prostate cancer | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $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