Bruising associated with the use of fluoxetine

To report a case of suspected fluoxetine-induced bruising and review the literature surrounding this rare adverse effect.

A 31-year-old white woman was diagnosed with depression and treated with fluoxetine. After fluoxetine 20 mg/d for 6 weeks, she reported bruising that was disproportionate to any trauma incurred. Her prothrombin time, partial thromboplastin time, and complete blood cell count were within normal limits. Fluoxetine was suspected to be the cause of this bruising. The patient did not want to discontinue the medication and has continued to bruise while continuing fluoxetine therapy.

Frequently encountered adverse effects caused by fluoxetine use include nausea, nervousness, and insomnia, but hematologic effects have also been reported. These include bleeding or bruising with prolonged bleeding time, increased prothrombin time and partial thromboplastin time, and thrombocytopenia. The mechanism behind these adverse effects is the prevention of serotonin-induced amplification of platelet aggregation by fluoxetine. Blockade of 5-hydroxytryptamine uptake in the platelets by fluoxetine reduces or depletes the platelet serotonin stores, thereby predisposing a patient with a mild underlying platelet disorder to a fluoxetine-induced hematologic disorder.

Fluoxetine has been reported to produce bruising, bleeding, and other hematologic disorders. It should be used with caution when treating patients with thrombocytopenia or with proven or suspected platelet dysfunction.