What the FDA labels say about taking them together
Exemestane and phenytoin
Exemestane's FDA label of September 12, 2024 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name exemestane. The exemestane label: “Drugs That Induce CYP 3A4 Co-medications that induce CYP 3A4 may significantly decrease exposure to exemestane.”
Check it at the source: the exemestane FDA label on DailyMed (effective September 12, 2024, Breckenridge Pharmaceutical, Inc.); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the exemestane label say about phenytoin?
Exemestane label, drug interactionsDrugs That Induce CYP 3A4 Co-medications that induce CYP 3A4 (e.g., rifampicin, phenytoin, carbamazepine, phenobarbital, or St. John's Wort) may significantly decrease exposure to exemestane.
Source: FDA drug label (Exemestane), Breckenridge Pharmaceutical, Inc., effective September 12, 2024 (SPL set 4e3fd382-19f5-4ded-ab22-39d5b1b2f366), via openFDA; the full label on DailyMed
What does the phenytoin label say about exemestane?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name exemestane 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
| Exemestane | Phenytoin | |
|---|---|---|
| Labeled for | Breast cancer | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.748 per tablet 25 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