Reported medication errors associated with methotrexate

Area of Science:

• Pharmacovigilance
• Patient Safety
• Medication Error Analysis

Background:

• Adverse event reports to the Food and Drug Administration (FDA) are crucial for identifying drug safety issues.
• Methotrexate is a widely used medication with a narrow therapeutic index, increasing the risk of medication errors.

Purpose of the Study:

• To investigate medication errors involving methotrexate reported to the FDA.
• To identify the causes, types, and consequences of methotrexate-related medication errors.

Main Methods:

• Analysis of adverse event reports submitted to the FDA between November 1997 and December 2001.
• Categorization of errors by indication for use, error type, and point of occurrence in the medication-use process.

Main Results:

• 106 cases of methotrexate medication errors were identified, resulting in 25 deaths (24%) and 48 serious outcomes (45%).
• Common errors included confusion regarding once-weekly dosing (30%) and other dosage inaccuracies (22%).
• Rheumatoid arthritis was the most frequent indication (42%), with errors attributed to prescribers (37%), patients (20%), dispensing (19%), and healthcare professionals (17%).

Conclusions:

• Medication errors involving methotrexate occur throughout the medication-use process.
• Dosage confusion, particularly with once-weekly schedules, is a significant contributing factor.
• These errors frequently lead to severe adverse events, including fatalities, underscoring the need for improved safety measures.