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Metamizole-induced agranulocytosis: utilisation trends, pharmacovigilance signals and regulatory risk-minimisation in

Oliver Wildner1, Isabelle Wenker1, Stephanie Storre1

  • 1Safety of Medicines Division, Swissmedic, Bern, Switzerland.

Swiss Medical Weekly
|June 29, 2026
PubMed

Insights

Metamizole (dipyrone) use increased in Switzerland, with a decline in fatal agranulocytosis cases despite rising reports. Regulatory actions and avoiding concomitant methotrexate are key for safe use.

Area of Science:

  • Pharmacovigilance and Drug Safety
  • Epidemiology of Adverse Drug Reactions

Background:

  • Metamizole (dipyrone) use is controversial due to the rare but severe risk of agranulocytosis.
  • Understanding drug utilization and adverse event reporting is crucial for patient safety.

Purpose of the Study:

  • To analyze metamizole utilization trends, spontaneous reporting of agranulocytosis, and regulatory actions in Switzerland.
  • To assess the risk-benefit profile of metamizole in the Swiss context.

Main Methods:

  • Utilisation data (defined daily doses) from national sales data (2014-2023).
  • Individual case safety reports (ICSRs) of metamizole-induced agranulocytosis from VigiBase (2014-2024).
  • Descriptive analysis of annual counts, fatal proportions, and utilization-normalized reporting rates.

Main Results:

  • Metamizole utilization increased by approximately 79% from 2014-2023.
  • Reports of metamizole-induced agranulocytosis rose, but the fatal proportion significantly declined.
  • Utilization-normalized reporting increased, yet fatal reports remained low and trended downward.
  • Concomitant methotrexate use was noted in a significant proportion of fatal Swiss cases.

Conclusions:

  • Despite increased utilization and reporting, metamizole's benefits are considered to outweigh risks when used appropriately.
  • Prompt management of symptoms and avoidance of concomitant methotrexate are critical for mitigating risks.
  • Ongoing monitoring of risk-minimization strategies is essential due to the known risks associated with widespread metamizole use.

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