Metamizole is an analgesic, antipyretic, and spasmolytic drug in Germany only approved for the treatment of severe pain or high fever that does not respond to other measures. In recent years, an increased use has been described among both adults and children, often against the approved indication. The most important side effect of metamizole is the development of agranulocytosis (neutrophil count < 500/µL). Incidence of metamizole-induced agranulocytosis (MIA) ranges depending on the study from 0.96 cases per million per year to 1:1602 per patient and metamizole prescription. The risk of agranulocytosis in children remains unclear, but is probably lower than in adults. Female gender and older age are associated with higher incidence, reflecting prescription distribution. MIA is dose-independent and risk seems to increase with duration of intake. In patients with past exposure, re-exposure may lead to rapid onset. MIA is believed to be induced either through immunologic or toxic mechanisms. MIA presents with fever, sore throat, fatigue, and mucosal inflammation, up to ulceration. Even in the case of suspected MIA, treatment with metamizole should be immediately paused and an examination of the blood cell count is required. In case of local or systemic infections, empirical therapy with broad-spectrum antibiotics should be administered. G-CSF therapy should be limited to patients with poor prognostic factors. The patient should be monitored closely until the neutrophil count returns to normal. Re-exposure to metamizole must be avoided.

中文翻译：

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安乃近诱发的粒细胞缺乏症 (MIA)：简要回顾

安乃近是一种镇痛、解热和解痉药物，在德国仅被批准用于治疗对其他措施无效的剧烈疼痛或高烧。近年来，成人和儿童的使用量有所增加，但往往违背了批准的适应症。安乃近最重要的副作用是出现粒细胞缺乏症（中性粒细胞计数<500/μL）。安乃近引起的粒细胞缺乏症 (MIA) 的发病率取决于研究范围，从每年每百万人 0.​​96 例到每名患者 1:1602 例和安乃近处方。儿童粒细胞缺乏症的风险尚不清楚，但可能低于成人。女性和年龄较大与较高的发病率相关，反映了处方分布。MIA 与剂量无关，风险似乎随着摄入时间的延长而增加。对于过去接触过的患者，再次接触可能会导致快速发病。MIA 被认为是通过免疫或毒性机制诱导的。MIA 表现为发烧、喉咙痛、疲劳和粘膜炎症，直至溃疡。即使在疑似 MIA 的情况下，也应立即暂停安乃近治疗，并需要检查血细胞计数。如果出现局部或全身感染，应采用广谱抗生素进行经验性治疗。G-CSF 治疗应仅限于预后不良的患者。应密切监测患者，直至中性粒细胞计数恢复正常。必须避免再次接触安乃近。