# Learning From the Uncommon in Common Practice: A Case Report on Metamizole-Induced Agranulocytosis

## TL;DR

This case report highlights a rare but serious side effect of metamizole, agranulocytosis, and emphasizes the need for caution and early detection in its use.

## Contribution

The paper presents a rare clinical case of metamizole-induced agranulocytosis with rapid onset and successful recovery.

## Key findings

- A 70-year-old patient developed agranulocytosis five days after starting metamizole treatment.
- Early discontinuation of metamizole and treatment with G-CSF and antibiotics led to full recovery.
- The case underscores the importance of vigilance and monitoring when using metamizole.

## Abstract

Agranulocytosis is a severe haematological disorder with multiple aetiologies, among which drug-induced causes are clinically significant. Metamizole is a non-opioid analgesic and antipyretic agent, used for the management of severe pain and high fever unresponsive to other measures. However, its use remains controversial due to the risk of metamizole-induced agranulocytosis (MIA), a rare but potentially life-threatening adverse reaction. This case aims to raise clinical awareness of MIA, highlighting the importance of its cautious use in daily practice. To our knowledge, it provides valuable clinical insight given the rapid onset of severe agranulocytosis, absence of alternative causative factors, and successful recovery with early intervention.

We present the case of a 70-year-old female patient who underwent elective abdominoplasty. Post-operative period was complicated with abdominal pain and sustained fever due to an abscess on the abdominal wall. Initial management with paracetamol and empiric antibiotics was ineffective. After surgical drainage, fever persisted and treatment with metamizole was started. Five days after starting metamizole, laboratory tests revealed agranulocytosis (90/µL). Metamizole was discontinued, and patient was placed under protective isolation. She received granulocyte-colony stimulating factor (G-CSF) and broad-spectrum antibiotics. Diagnostic workup excluded other sources of infection and neoplastic causes of agranulocytosis. Clinical and laboratory findings suggested MIA. Patient completed three days of G-CSF and 30 days of antibiotics, achieving full clinical and haematological recovery, with no recurrence during follow-up.

Metamizole-induced agranulocytosis is a rare but serious adverse reaction requiring early recognition. This case illustrates the importance of maintaining clinical vigilance and performing early haematological monitoring, particularly in high-risk patients. Clinicians should exercise caution when prescribing metamizole, limiting its use to well-justified indications and short durations. Continuous pharmacovigilance and further epidemiological studies are essential to define the true incidence, risk factors, and optimal management strategies.