Relationship of serotonergic antidepressants and need for blood transfusion in orthopedic surgical patients

Background: Several reports of various bleeding problems associated with the use of serotonergic antidepressants have been published. However, no information concerning the effect of these drugs on perioperative blood loss and blood transfusion requirements during orthopedic surgery is available. The objective of this study was to determine the association between use of serotonergic antidepressants and perioperative blood loss and transfusion in orthopedic surgical patients. Methods: A retrospective follow-up study, using routinely collected hospital and pharmacy data, was conducted among all orthopedic patients undergoing surgery from January 1, 1999, through December 31, 2000. The actual blood transfusion requirements and blood loss during surgery were assessed. Patients were divided into 3 groups for comparison: users of serotonergic antidepressants, users of nonserotonergic antidepressants, and nonusers of antidepressants. The Medical Ethics Committee approved the study protocol, and informed consent was obtained from all patients or their legal relatives. Results: A total of 520 subjects with evaluable data participated in the study. The risk of blood transfusion almost quadrupled for the serotonergic antidepressant group as compared with the nonusers (adjusted odds ratio, 3.71; 95% confidence interval, 1.35-10.18). Patients using nonserotonergic antidepressants had no increased risk (odds ratio, 0.74; 95% confidence interval, 0.10-5.95). Conclusions: Use of serotonergic antidepressants is associated with an increased risk of bleeding and subsequent need for blood transfusion during orthopedic surgery. The bleeding could be attributed to inhibition of serotonin-mediated platelet activation.