Fluoxetine and Thrombocytopenia in Bipolar Disorder: Unveiling a Rare Adverse Effect

Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), is widely prescribed to treat depressive episodes but is rarely associated with hematological side effects such as thrombocytopenia. This report presents the case of a 26-year-old Omani man with bipolar disorder and chronic idiopathic thrombocytopenia who developed a significant decline in platelet count while being treated with fluoxetine during a depressive episode. Thrombocytopenia, defined as a platelet count below 150 × 10³/µL, can result from various factors, including immune dysregulation, infections, or drug-induced effects. Prior to initiating fluoxetine, the patient's platelet levels had been stable. However, it progressively declined during treatment, eventually reaching a critical level of 34 × 10³/µL. Extensive investigations ruled out other causes, implicating fluoxetine as the primary contributor. Discontinuing the medication led to a gradual improvement in the patient's platelet count. This case underscores the importance of promptly recognizing platelet decline and the need for healthcare providers to remain vigilant about SSRI-induced hematological side effects, especially in patients with pre-existing thrombocytopenia.