Increased
methotrexate toxicity, sometimes life-threatening, has been seen in a few patients also taking an
NSAID, whereas other patients have taken
NSAIDs with
methotrexate uneventfully. The mechanism of this interaction suggests that all
NSAIDs have the potential to interact similarly. The
pharmacokinetics of methotrex- ate can also be changed by some
NSAIDs.
Concurrent use need not be avoided but close monitoring is necessary. The risk appears to be lowest in those taking low-dose
methotrexate for psoriasis or rheumatoid arthritis, with normal
renal function. Patients must be counselled regarding non-prescription
NSAIDs.