Methotrexate and NSAID Therapy: Guidelines for Combined Use

Safety of Combined Therapy

The American Academy of Dermatology notes that NSAIDs can be given concurrently with low-dose methotrexate in patients with normal renal function, but caution is needed due to potential interactions that may increase methotrexate toxicity 1, 2
The British Association of Dermatologists guidelines state that drug interactions with methotrexate usually occur due to altered pharmacokinetics, such as displacement of protein binding and reduced renal elimination 3
Patients should be made aware of the need to report features of methotrexate toxicity, such as mouth ulceration and any changes in prescription, including concomitant use of NSAIDs 4

NSAIDs can reduce renal elimination of methotrexate, leading to increased serum levels and potential toxicity 3

In pediatric patients, NSAIDs or salicylates can be given concurrently with low-dose methotrexate in children with normal renal function, with a Strength of Recommendation B and Level of Evidence II 1, 2
Patients with risk factors, such as renal insufficiency or advanced age, may need closer monitoring when using methotrexate, especially with concurrent NSAID use 4
Methotrexate dosage should be reduced in those with suboptimal renal function, and avoided in patients on dialysis or with creatinine clearance <20 mL/min 5

Patients on both methotrexate and NSAIDs should have more frequent monitoring of liver function tests to monitor for hepatotoxicity 3
Patients on both methotrexate and NSAIDs should have more frequent monitoring of renal function tests, especially in elderly patients or those with pre-existing renal impairment 3
Withhold or decrease methotrexate dose if total white blood cell count <3 × 10^9/L, neutrophils <10 × 10^9/L, platelets <100,000/L, or liver enzymes ≥3 × upper limit of normal for 2 consecutive months 2

Case reports have documented toxicity particularly with naproxen, diclofenac, ibuprofen, and indomethacin when combined with methotrexate 3

Elderly patients and those with reduced renal function are at higher risk for potential interactions between methotrexate and NSAIDs 3
The European League Against Rheumatism (EULAR) guidelines recommend that NSAIDs "should be used at the minimum effective dose for the shortest time possible, after evaluation of gastrointestinal, renal, and cardiovascular risks" in patients with rheumatoid arthritis 6

Perform a comprehensive medication review before initiating combination therapy to identify all potential drug interactions 3
Educate patients to report any unusual symptoms promptly, particularly those suggesting methotrexate toxicity, such as mouth ulcers, unusual bruising, severe sore throat, or dyspnea 3, 4
If NSAIDs must be used with methotrexate, consider scheduling the NSAID on different days than methotrexate to minimize interaction risk 4

The British Journal of Cancer recommends that NSAIDs should NOT be used with methotrexate in cancer patients receiving high-dose methotrexate due to severe toxicity risk 7

The American College of Rheumatology suggests that for low-dose methotrexate (≤15 mg/week) used in rheumatoid arthritis, psoriatic arthritis, or juvenile idiopathic arthritis, NSAIDs can be prescribed with appropriate precautions, as recommended by the Annals of the Rheumatic Diseases 8
The Arthritis and Rheumatology journal recommends that NSAIDs may be used as first-line treatment for musculoskeletal symptoms in rheumatoid arthritis and psoriatic arthritis, with combination with methotrexate being acceptable with monitoring 8

The Arthritis and Rheumatology journal recommends baseline assessment, including complete blood count (CBC) with differential, liver function tests (ALT, AST), and renal function tests (BUN, creatinine, urinalysis) before initiating combination therapy 9
The American Academy of Family Physicians suggests that patients with concurrent nephrotoxic medications (ACE inhibitors, diuretics) should avoid or use extreme caution with NSAIDs and methotrexate 10

The British Journal of Cancer recommends considering proton pump inhibitor co-prescription for patients with GI risk factors when using NSAIDs and methotrexate 7
The American College of Rheumatology suggests that patients must be educated to report immediately any unusual bruising or bleeding, severe sore throat, dark urine, or shortness of breath when using NSAIDs and methotrexate 7

The Arthritis Care and Research journal recommends that in stable patients on both TNF inhibitors and NSAIDs, consider withdrawing NSAIDs rather than continuing both due to uncertain benefit and toxicity risk 11