Reported medication errors associated with methotrexate.
OBJECTIVE
Medication errors reported to FDA as adverse events in which methotrexate was identified as a possible contributor were studied.


METHODS
All adverse-event reports submitted to FDA between November 1997 and December 2001 indicating potential medication errors involving methotrexate were analyzed to determine the indication for use, the type of error, and the point in the medication-use process where the error occurred.


RESULTS
A total of 106 cases of reported medication errors associated with methotrexate were identified, including errors resuiting in 25 deaths (24%) and 48 other serious outcomes (45%). The most common types of errors involved confusion about the once-weekly dosage schedule (30%) and other dosage errors (22%). The most frequently involved indication for use was rheumatoid arthritis (42%). Of the errors, 39 (37%) were attributable to the prescriber, 21 (20%) to the patient, 20 (19%) to dispensing, and 18 (17%) to administration by a health care professional.


CONCLUSIONS
A review of medication errors involving methotrexate revealed that errors occurred during all phases of use, often resulted from confusion about dosage, and often caused death or other serious adverse effects.
Moore
Thomas J
TJ
Drug Safety and Policy, Institute for Safe Medication Practices, Huntingdon Valley, PA 19006, USA. tmoore@ismp.org
Walsh
Christopher S
CS
Cohen
Michael R
MR
D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems; D000368:Aged; D004334:Drug Administration Schedule; D004348:Drug Labeling / Q000706:statistics & numerical data; D005260:Female; D005493:Folic Acid Antagonists / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008508:Medication Errors / Q000706:statistics & numerical data*; D008727:Methotrexate / Q000008:administration & dosage* / Q000627:therapeutic use; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014481:United States; D014486:United States Food and Drug Administration
D005493:Folic Acid Antagonists; D008727:Methotrexate