Abstract
BACKGROUND: Mirtazapine is a frequently prescribed psychotropic drug for depression in older age. It is considered safe and has a side-effect profile uniquely favorable to an older person affected by reduced appetite, difficulty maintaining body weight, or insomnia. However, it is largely unknown that mirtazapine can cause a dangerous decline in neutrophil count. CASE PRESENTATION: We present a case of mirtazapine-induced severe neutropenia in a 91-year-old white British woman requiring drug withdrawal and granulocyte-colony stimulating factor administration. CONCLUSION: This case is of significance because mirtazapine is regarded as a safe, and often preferable, antidepressant in older age. However, this case demonstrates a rare, life-threatening side effect of mirtazapine and calls for greater pharmacovigilance when prescribing it. There is no previous report of mirtazapine-induced neutropenia requiring drug withdrawal and granulocyte-colony stimulating factor administration in an older person.