NutriStack
Methotrexate and Naproxen, a caution.
Naproxen, like other NSAIDs, reduces renal clearance of methotrexate. The longer half-life of naproxen may pose even greater accumulation risk compared to short-acting NSAIDs.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Methotrexate and Naproxen
- Pair type
- Caution
- Evidence (highest tier)
- Strong
- Source citations
- 1 source
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Strong evidence
Caution
What is happening. Naproxen, like other NSAIDs, reduces renal clearance of methotrexate. The longer half-life of naproxen may pose even greater accumulation risk compared to short-acting NSAIDs.
Mechanism. Naproxen inhibits renal prostaglandin synthesis, reducing glomerular filtration rate and competing with methotrexate for tubular secretion.
Recommendation. Avoid concurrent use with high-dose methotrexate. Use with extreme caution alongside low-dose methotrexate. Monitor renal function and CBC regularly.
Sources (1)
Stack Score
How this pair moves the number.
Effect on the composite score
If both Methotrexate and Naproxen are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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