What the FDA labels say about taking them together
Fosphenytoin and sertraline
Fosphenytoin's FDA label of May 18, 2025 names sertraline in its drug interactions section, and sertraline's label names fosphenytoin too. The sertraline label: “Phenytoin is a narrow therapeutic index drug. ZOLOFT may increase phenytoin concentrations.”
Check it at the source: the fosphenytoin FDA label on DailyMed (effective May 18, 2025, Pfizer Laboratories Div Pfizer Inc); the sertraline FDA label on DailyMed (effective August 8, 2023, Viatris Specialty LLC).
What does the fosphenytoin label say about sertraline?
Fosphenytoin label, drug interactionsInteracting Agent: Antidepressants; Examples: Fluoxetine, fluvoxamine, sertraline
Source: FDA drug label (CEREBYX), NDA020450 (Parke Davis), as published by Pfizer Laboratories Div Pfizer Inc, effective May 18, 2025 (SPL set de5a6711-4abb-4c3d-a18b-266b094ace11), via openFDA; the full label on DailyMed
What does the sertraline label say about fosphenytoin?
Sertraline label, drug interactionsClinical Impact: Phenytoin is a narrow therapeutic index drug. ZOLOFT may increase phenytoin concentrations. Intervention: Monitor phenytoin levels when initiating or titrating ZOLOFT. Reduce phenytoin dosage if needed. Examples: phenytoin, fosphenytoin Drugs that Prolong the QTc Interval
Source: FDA drug label (Sertraline Hydrochloride, NDA020990), Mylan Pharmaceuticals Inc., effective September 15, 2024 (SPL set 1a58062b-e635-431a-908d-2651c6a4a21c), via openFDA
Source: FDA drug label (Zoloft), Viatris Specialty LLC, effective August 8, 2023 (SPL set fda754f6-d0f3-4dce-a17a-927d64f912f7), 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
| Fosphenytoin | Sertraline | |
|---|---|---|
| Labeled for | Seizures and epilepsy | Depression, Anxiety |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | $0.0507 per tablet 100 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