METHOTREXATE AND PENICILLINS
Reduced clearance and acute methotrexate toxicity has been attributed to the
concurrent use of various penicillins (amoxicillin, benzylpenicillin, carbenicillin, dicloxacillin, flucloxacillin, mezlocillin, oxacillin, phenoxymethylpenicillin, piperacillin, and ticarcillin) in a small number of case reports.
Serious interactions between methotrexate and penicillins are uncommon. Risk
factors are as yet unknown and even patients taking low doses of methotrexate
have been affected. Given the current evidence monitoring is advisable. One
recommendation is to carry out twice-weekly platelet and white cell counts for
2 weeks initially, with the measurement of methotrexate levels if toxicity is
suspected.
concurrent use of various penicillins (amoxicillin, benzylpenicillin, carbenicillin, dicloxacillin, flucloxacillin, mezlocillin, oxacillin, phenoxymethylpenicillin, piperacillin, and ticarcillin) in a small number of case reports.
Serious interactions between methotrexate and penicillins are uncommon. Risk
factors are as yet unknown and even patients taking low doses of methotrexate
have been affected. Given the current evidence monitoring is advisable. One
recommendation is to carry out twice-weekly platelet and white cell counts for
2 weeks initially, with the measurement of methotrexate levels if toxicity is
suspected.