Selective serotonin reuptake inhibitor-induced disturbances of haemostasis - Mechanisms and therapeutic implications

Serotonin (5-hydroxytryptamine; 5-HT) has important peripheral functions that include roles in platelet function, primarily in aggregation and modulation of Vascular tone. Platelet serotonin is derived predominantly via uptake from the enterochromaffin system. Selective serotonin reuptake inhibitors (SSRIs) substantially reduce platelet serotonin stores via uptake inhibition. SSRIs are associated with infrequent clinical reports of haemostatic dysfunction, primarily easy bruising. These clinical reports have not, however, been paralleled by prospective studies, which have not found any disturbances in haemostatic function secondary to SSRI therapy. SSRI-associated haemostatic dysfunction appears to be a rare adverse event, and has not been reported to be associated with mortality or substantial morbidity. Nevertheless, a high index of suspicion is warranted in any patient on SSRI therapy who develops unexplained changes in haemostatic function.