Methotrexate and Sulfasalazine interaction
Methotrexate and Sulfasalazine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Methotrexate (Xatmep) label · effective 2026-05-28
Monitor patients receiving XATMEP with other potential hepatotoxins (e.g., azathioprine, retinoids, and sulfasalazine) for possible signs of hepatotoxicity.
Caution should be used when NSAIDs and salicylates are administered concomitantly with lower doses of methotrexate, including XATMEP.
Aspirin, NSAIDs, and/or low dose steroids may be continued, although the possibility of increased toxicity with concomitant use of NSAIDs including salicylates has not been fully explored.
From the Sulfasalazine label · effective 2026-08-25
When daily doses of sulfasalazine 2 g and weekly doses of methotrexate 7.5 mg were coadministered to 15 rheumatoid arthritis patients in a drug-drug interaction study, the pharmacokinetic disposition of the drugs was not altered.
Daily doses of sulfasalazine 2 g (maximum 3 g) and weekly doses of methotrexate 7.5 mg (maximum 15 mg) were administered alone or in combination to 310 rheumatoid arthritis patients in two controlled 52-week clinical studies.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.