What the FDA labels say about taking them together
Clozapine and phenytoin
Clozapine's FDA label of June 6, 2025 names phenytoin in its drug interactions section, and phenytoin's label names clozapine too. The phenytoin label: “Interacting Agent: Other; Examples: Albendazole, chlorpropamide, clozapine, cyclosporine, digoxin, disopyramide, folic acid, methadone, mexiletine, praziquantel, quetiapine”
Check it at the source: the clozapine FDA label on DailyMed (effective June 6, 2025, HLS Therapeutics (USA), Inc.); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the clozapine label say about phenytoin?
Clozapine label, drug interactionsStrong CYP3A4 inducers include carbamazepine, phenytoin, St. John’s wort, and rifampin.
Source: FDA drug label (Clozaril), NDA019758 (Heritage Life), as published by HLS Therapeutics (USA), Inc., effective June 6, 2025 (SPL set 90876802-0e3a-44c9-9ff7-1754dfbe736a), via openFDA; the full label on DailyMed
What does the phenytoin label say about clozapine?
Phenytoin label, drug interactionsInteracting Agent: Other; Examples: Albendazole (decreases active metabolite), chlorpropamide, clozapine, cyclosporine, digoxin, disopyramide, folic acid, methadone, mexiletine, praziquantel, quetiapine
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
| Clozapine | Phenytoin | |
|---|---|---|
| Labeled for | Schizophrenia | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.610 per tablet 100 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