Study identification

EU PAS number

EUPAS41314

Study ID

48963

Official title and acronym

Metamizole and risk of agranulocytosis

DARWIN EU® study

No

Study countries

Spain

Study description

Metamizole is an analgesic and antipyretic marketed for more than 50 years in our country. It is a widely used drug in Spain with the indications of analgesic in different situations of moderate or severe acute pain, and antipyretic when other alternatives are not effective. Agranulocytosis is one of its possible adverse reactions and, although it is rare and has a very low frequency, it is serious and can lead to the death of the patient. It is characterized by a decrease in peripheral neutrophil count to less than <500 cells/mcl due to immunologic or cytotoxic mechanisms. Most, but not all, instances of agranulocytosis result from exposure to drugs (idiosyncratic drug-induced agranulocytosis), and either the drug itself or a metabolite may be causative. Despite agranulocytosis is a well-known adverse reaction for metamizole, there has been an increase recently in the reporting of cases of agranulocytosis to the Spanish pharmacovigilance system. Despite it is a very serious reaction that continues appearing, no study has been performed in years in our country and none with BIFAP. There is a need to carry out a new pharmacoepidemiological study that addresses the issues raised, using secondary sources of information that may be available in health information systems.

Research question and objectives:
Objective: Estimation of the risk of agranulocytosis associated with the use of metamizole compared to other analgesics / anti-inflammatories with similar use profile, in the BIFAP population.

Study design: comparative cohort study. Population: New users of metamizole or other analgesics / anti-inflammatories aged above 2 years, without alterations in bone marrow function (e.g. during or after treatment with cytostatic agents) or diseases of the hematopoietic system.

Data analysis: Survival analyses with Cox proportional hazard regression models.

Study status

Finalised
Research institutions and networks

Institutions

Contact details

Elisa Martín-Merino 0000-0002-3576-8605

Primary lead investigator
ORCID number:
0000-0002-3576-8605

Study timelines

Date when funding contract was signed

Planned:
Actual:

Study start date

Planned:
Actual:

Data analysis start date

Planned:

Date of interim report, if expected

Planned:

Date of final study report

Planned:
Actual:
Sources of funding
Other

More details on funding

AEMPS's own resources. No funding has been received.
Regulatory

Was the study required by a regulatory body?

No

Is the study required by a Risk Management Plan (RMP)?

Not applicable