People with inflammatory diseases are often treated with methotrexate. Unlike for cancer, for this indication it is only used once a week, which is a rather unusual dosage frequency. There have been repeated instances of methotrexate being taken daily instead of weekly by mistake. An overdose of this nature can have serious health consequences or even be fatal. The Swiss Patient Safety Foundation, Swissmedic and ToxInfoSuisse have long been pointing out this danger [1-3], which is why a Quick Alert [4] has already been published.

Possible measures

Specific measures can prevent accidental overdoses. For example, warning labels on the tablet packaging that draw attention to the correct dosage. Technological barriers also help at the prescription stage. Adjusting package sizes can also be an important preventive measure. However, it is not yet known to what extent such measures have already been applied in the Swiss healthcare system and how many patients might be impacted by them.

Research project

A research project in 2021–22 will therefore answer the following questions:

  1. How widespread are measures in public pharmacies and hospitals to prevent accidental methotrexate overdoses?
  2. How frequently are low doses of methotrexate prescribed in Switzerland?

To answer these questions, surveys will be conducted among pharmacies in two regions and in hospital pharmacies throughout Switzerland. The consumption of methotrexate will also be analyzed by means of a database.

Project goals

The findings will be published in a scientific journal. The results will show where in the Swiss healthcare system there is a need for improvement in the prevention of methotrexate overdoses.  This will help patients with inflammatory diseases who are being treated with methotrexate in Switzerland to be cared for more safely in the future.


  1. Weiler S et al. Panzytopenie unter Methotrexat. Swiss Med Forum 2017;17:594–596.
  2. Abegglen J et al. Akzidentelle Überdosierung von Methotrexat. Schweizerische Ärztezeitung 2012;93:1818.
  3. Damke B et al. Akzidentelle Überdosierungen von Low Dose Methotrexat. Schweizerische Ärztezeitung 2015;96:1845.
  4. Swiss Patient Safety Foundation. Quick-Alert Nr. 28 - Methotrexat-Intoxikation. 2012.

Dr. Lea Brühwiler

Research assistant
T +41 43 244 14 90