What happens when you take methotrexate with NSAIDs?
Methotrexate can interact with some NSAIDs because the NSAIDs may reduce methotrexate clearance from the body (for example, by affecting kidney transport mechanisms). When clearance drops, methotrexate levels can rise and toxicity risk increases, including mouth sores, infections, severe nausea/vomiting, or (in more serious cases) bone marrow suppression and kidney injury [1].
This interaction risk is most clinically important with higher-dose methotrexate (commonly used in oncology) and with factors that already increase methotrexate exposure, such as kidney impairment or dehydration.
Which NSAIDs are more concerning with methotrexate?
The interaction potential is greatest with NSAIDs that are strongly associated with impaired renal drug elimination or reduced methotrexate clearance. In practice, clinicians often use the cautious approach of:
- avoiding NSAIDs during periods when methotrexate exposure is expected to peak (depending on dosing schedule), and/or
- using the lowest effective NSAID dose for the shortest time when an NSAID is needed.
Specific “least risky” vs “most risky” NSAIDs depend on patient kidney function, methotrexate dose, age, and other medications. If you tell me the exact methotrexate dose (mg/week or mg/m²) and which NSAID (and dose), I can help you think through the risk level more concretely.
Is the risk different for low-dose methotrexate (e.g., for rheumatoid arthritis) vs high-dose?
Yes. The interaction is usually discussed as a bigger concern when methotrexate levels are more likely to build up—such as with:
- reduced kidney function
- dehydration
- interacting medicines that also raise methotrexate exposure
- higher-dose methotrexate regimens
Low-dose methotrexate used for inflammatory diseases is commonly prescribed alongside pain control options, but NSAID use still needs clinician oversight because kidney function and the exact regimen vary widely between patients.
What patient factors make the interaction more dangerous?
People are more vulnerable if they have:
- kidney disease or reduced estimated glomerular filtration rate
- older age
- dehydration (vomiting/diarrhea, poor oral intake)
- concurrent medicines that affect kidneys or drug transport
- folate deficiency or prior methotrexate intolerance
If any of these apply, you generally want a prescriber/pharmacist to review the plan before using an NSAID.
What symptoms should you watch for?
If methotrexate toxicity occurs, symptoms can include:
- mouth sores or inflammation of the mouth (stomatitis)
- unusual bruising or bleeding, fatigue, frequent infections (bone marrow suppression signs)
- severe nausea/vomiting or diarrhea
- worsening kidney symptoms (e.g., decreased urination, swelling)
Stop and get urgent medical advice if you develop severe symptoms or signs of infection, bleeding, or significant dehydration.
What should you do if you already took both?
If you took methotrexate and an NSAID once, the key question is whether you have risk factors (kidney problems, dehydration, interacting drugs) and whether symptoms appear. Because methotrexate timing can matter, contacting your prescriber or pharmacist promptly is the safest next step—especially if this was an unplanned combination or you’re taking high-dose methotrexate.
Are there alternatives to NSAIDs for pain while on methotrexate?
Options depend on your condition and pain type. Commonly considered alternatives include acetaminophen (paracetamol) for pain/fever, since it does not work the same way as NSAIDs and is not typically used to control inflammatory pain in the same class. Your prescriber should still confirm it fits your situation (liver disease, alcohol use, total daily dose limits, etc.).
How to check your specific situation
To tailor the safest answer, I’d need:
- your methotrexate regimen (dose and schedule, e.g., 15 mg weekly vs daily vs high-dose)
- which NSAID you mean (ibuprofen, naproxen, diclofenac, indomethacin, etc.) and dose
- your kidney function status (any known kidney disease or recent creatinine/eGFR)
- age and whether you’re dehydrated or have had vomiting/diarrhea
- other medicines (especially ones that also affect kidneys or drug clearance)
Source
[1] DrugBank: Methotrexate (Drug interaction information, including NSAID-related interaction risk). https://go.drugbank.com/drugs/DB00520