Deaths following methotrexate overdoses by medical staff.

Methotrexate (MTX) is an effective disease modifying antirheumatic drug (DMARD) with a relatively safe profile, and it is widely used to treat neoplastic diseases and dermatologic and rheumatologic disorders. As indications for use of MTX increase, more accidental overdoses are noted to occur. Typical problems include deficiencies in labeling, instructions, or packaging, as well as erroneous use. We describe 5 fatal cases of repeated oral overdose of MTX prescribed by physicians in the treatment of rheumatoid arthritis to focus attention on the design of the underlying system and the organizational practices as sources of problems.