Two reports describe a reduction in the excretion of
methotrexate in 2 patients taking
omeprazole. However, similar elevations in
methotrexate levels in another patient taking
omeprazole were independent of
omeprazole use. One patient had myalgia and elevated 7-hydroxymethotrexate levels when treated with
methotrexate and pan- toprazole, and in 3 patients
lansoprazole appeared to reduce
methotrexate clearance and increase its levels.
The general significance of this interaction is unclear, but until more is known it would be prudent to bear this interaction in mind as a potential cause of
methotrexate toxicity.