What the FDA labels say about taking them together
Methotrexate and natalizumab
Natalizumab's FDA label of March 21, 2025 names methotrexate in its drug interactions section; the methotrexate labels PlainMeds reads (4) do not name natalizumab. The natalizumab label: “DRUG INTERACTIONS Because of the potential for increased risk of PML and other infections, Crohn’s disease patients receiving natalizumab products should not be treated with concomitant immunosuppressants or inhibitors …”
Check it at the source: the methotrexate FDA label on DailyMed (effective May 27, 2026, Accord Healthcare Inc.); the natalizumab FDA label on DailyMed (effective March 21, 2025, Biogen Inc.).
What does the methotrexate label say about natalizumab?
Methotrexate's label (effective May 27, 2026) and its 3 other brand-application labels do not name natalizumab in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Methotrexate), Accord Healthcare Inc., effective May 27, 2026 (SPL set 874c7f43-a3be-4236-89cc-24c44e3c5813), via openFDA; the full label on DailyMed
What does the natalizumab label say about methotrexate?
Natalizumab label, drug interactionsDRUG INTERACTIONS Because of the potential for increased risk of PML and other infections, Crohn's disease patients receiving TYSABRI should not be treated with concomitant immunosuppressants (e.g., 6-mercaptopurine, azathioprine, cyclosporine, or methotrexate) or inhibitors of TNF-α, and corticosteroids should be tapered in those patients with Crohn's disease who are on chronic corticosteroids when they start TYSABRI therapy [ see Indications and Usage ( 1.2 ), Warnings and Precautions ( 5.1 , 5.6 ) ].
Natalizumab label, warnings and precautionsPrior treatment with an immunosuppressant (e.g., mitoxantrone, azathioprine, methotrexate, cyclophosphamide, mycophenolate mofetil).
Source: FDA drug label (Tyruko, BLA761322), Sandoz Inc, effective October 31, 2025 (SPL set ef653c36-dd4b-4e71-9d2d-40b8fea24b67), via openFDA
Source: FDA drug label (TYSABRI), Biogen Inc., effective March 21, 2025 (SPL set c5fdde91-1989-4dd2-9129-4f3323ea2962), 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
| Methotrexate | Natalizumab | |
|---|---|---|
| Labeled for | Rheumatoid arthritis, Psoriasis, Leukemia, lymphoma and myeloma, Breast cancer | Multiple sclerosis |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.158 per tablet 2.5 mg tablet | n/a |
| Shortage now | In shortage | 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