Analgesic-dose
aspirin slightly reduces the clearance of
methotrexate. Concurrent use may increase the
incidence of
toxicity (pancytopenia, pneumonitis).
Regular antiplatelet-dose
aspirin in patients stabilised on
methotrexate seems unlikely to cause a significant problem. With analgesic-dose
aspirin the risks are likely to be lowest in those taking low-dose
methotrexate for
psoriasis or rheumatoid
arthritis. Patients should be counselled regarding non-prescription
aspirin use. Patients should be told to report any sign or symptom suggestive of
infection, particularly
sore throat (which might possibly indicate that white cell counts have fallen) or dyspnoea or cough (suggestive of
pulmonary toxicity).