What the FDA labels say about taking them together
Pemetrexed and sepiapterin
Sepiapterin's FDA label of April 24, 2026 names pemetrexed in its drug interactions section; the pemetrexed labels PlainMeds reads (4) do not name sepiapterin. The sepiapterin label: “DRUG INTERACTIONS Dihydrofolate Reductase (DHFR) Inhibitors: Avoid concomitant use. Sepiapterin Reductase (SR) Inhibitors:”
Check it at the source: the pemetrexed FDA label on DailyMed (effective October 8, 2025, Avyxa Pharma, LLC); the sepiapterin FDA label on DailyMed (effective April 24, 2026, PTC Therapeutics Inc.).
What does the pemetrexed label say about sepiapterin?
Pemetrexed's label (effective October 8, 2025) and its 3 other brand-application labels do not name sepiapterin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (AXTLE), Avyxa Pharma, LLC, effective October 8, 2025 (SPL set 9582c46c-d8b0-44b7-a2ee-9c86f5e9b7b1), via openFDA; the full label on DailyMed
What does the sepiapterin label say about pemetrexed?
Sepiapterin label, drug interactionsDRUG INTERACTIONS Dihydrofolate Reductase (DHFR) Inhibitors: Avoid concomitant use (e.g., trimethoprim, methotrexate, trimetrexate, pemetrexed, pralatrexate, raltitrexed, or piritrexim). ( 7.1 ) Sepiapterin Reductase (SR) Inhibitors:
Source: FDA drug label (Sephience), PTC Therapeutics Inc., effective April 24, 2026 (SPL set 32ac719c-49f0-4105-9c46-18c19583a5c2), 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
| Pemetrexed | Sepiapterin | |
|---|---|---|
| Labeled for | Lung cancer | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | n/a |
| 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