Introduction Clozapine, a second-generation antipsychotic (SGA), is considered the gold standard medication to treat patients with treatment-resistant schizophrenia (TRS). Despite its efficacy, clozapine is associated with adverse effects, notably neutropenia and agranulocytosis. Other hematological adverse effects are less common. Severe anemia is a rare adverse effect seldom reported in the literature and is typically associated with pure red cell aplasia (PRCA). Nevertheless, the benefits of clozapine in managing TRS make rechallenge a reasonable option. Case Report We present the case of a 35-year-old man with TRS, resistant to previous antipsychotics, who experienced severe anemia during clozapine treatment. An investigation for clozapine-induced anemia revealed PRCA on myelogram. After discontinuing clozapine, the patient’s hemoglobin levels recovered. Subsequent treatments with olanzapine, zuclopenthixol, and aripiprazole proved ineffective, leading us to consider a clozapine rechallenge. The rechallenge, monitored for 58 days, resulted in improved psychiatric symptoms and stable hemoglobin levels. The patient remained stable during 6 months of follow-up, with no hematological changes. Discussion PRCA is a very rare adverse effect of clozapine. The cause of drug-induced PRCA is still unknown; for clozapine, there are no studies. Rechallenge after a severe and rare adverse effect is a complex decision. This case is the first to report a successful clozapine rechallenge following severe anemia without other blood dyscrasias, emphasizing the imperative need for close monitoring during the rechallenge process. Further study is warranted to understand the predictive factors for a successful outcome in clozapine rechallenges.

中文翻译：

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氯氮平诱发严重贫血后成功再次服用氯氮平：病例报告

简介 氯氮平是第二代抗精神病药 (SGA)，被认为是治疗难治性精神分裂症 (TRS) 患者的金标准药物。尽管氯氮平有效，但它也有不良反应，特别是中性粒细胞减少症和粒细胞缺乏症。其他血液学不良反应不太常见。严重贫血是一种罕见的不良反应，文献中很少报道，通常与纯红细胞再生障碍性贫血 (PRCA) 相关。尽管如此，氯氮平在治疗 TRS 方面的优势使得重新挑战成为一个合理的选择。病例报告 我们介绍了一名患有 TRS 的 35 岁男性病例，他对先前的抗精神病药物有耐药性，在氯氮平治疗期间出现严重贫血。对氯氮平引起的贫血的调查显示，脊髓造影显示有 PRCA。停用氯氮平后，患者的血红蛋白水平恢复。随后用奥氮平、珠氯哌噻吨和阿立哌唑治疗无效，导致我们考虑重新服用氯氮平。经过 58 天的监测，再次挑战的结果是精神症状改善，血红蛋白水平稳定。患者在 6 个月的随访期间保持稳定，没有血液学变化。讨论 PRCA 是氯氮平的一种非常罕见的不良反应。药物引起的 PRCA 的病因尚不清楚；对于氯氮平，尚无研究。严重且罕见的不良反应后重新挑战是一个复杂的决定。该病例是第一个报告在严重贫血后成功重新服用氯氮平而没有其他血液恶液质的病例，强调在重新服用过程中密切监测的必要性。需要进一步研究以了解氯氮平再次挑战成功结果的预测因素。