What the FDA labels say about taking them together
Cyclosporine and fosphenytoin
Fosphenytoin's FDA label of May 18, 2025 names cyclosporine in its drug interactions section; the cyclosporine labels PlainMeds reads (4) do not name fosphenytoin. The fosphenytoin label: “Interacting Agent: Other; Examples: Albendazole, chlorpropamide, clozapine, cyclosporine, digoxin, disopyramide, folic acid, methadone, mexiletine, praziquantel, quetiapine”
Check it at the source: the cyclosporine FDA label on DailyMed (effective August 10, 2026, Novartis Pharmaceuticals Corporation); the fosphenytoin FDA label on DailyMed (effective May 18, 2025, Pfizer Laboratories Div Pfizer Inc).
What does the cyclosporine label say about fosphenytoin?
Cyclosporine's label (effective August 10, 2026) and its 3 other brand-application labels do not name fosphenytoin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Neoral), Novartis Pharmaceuticals Corporation, effective August 10, 2026 (SPL set 94461af3-11f1-4670-95d4-2965b9538ae3), via openFDA; the full label on DailyMed
What does the fosphenytoin label say about cyclosporine?
Fosphenytoin 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 (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
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
| Cyclosporine | Fosphenytoin | |
|---|---|---|
| Labeled for | Organ transplant rejection, Rheumatoid arthritis | Seizures and epilepsy |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $1.04 per unit 0.05% eye emulsion | n/a |
| 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