Table 1.

Common drug-drug interactions with MTX

TMP-SMXBone marrow suppression, renal toxicity≥ 17 case reports and 1 retrospective case-control study
Penicillins and cephalosporins (eg, amoxicillin, cephalexin)Bone marrow suppression≥ 5 case reports and multiple interaction studies
NSAIDs (eg, high-dose ASA, indomethacin, ibuprofen)Bone marrow suppression≥ 30 case reports, 2 retrospective observational studies, and multiple interaction studies
  • ASA—acetylsalicylic acid, MTX—methotrexate, NSAIDs—nonsteroidal anti-inflammatory drugs, TMP-SMX—trimethoprim-sulfamethoxazole.

  • * Rare drug-drug interactions have also been reported with MTX and quinolones, macrolides, retinoids, proton pump inhibitors, isoniazid, ranitidine, probenecid, and theophylline; however, the reliability and clinical importance of these potential interactions are substantially uncertain.

  • Data from Bourré-Tessier and Haraoui7 and van Roon et al.8