The association between use of serotonergic antidepressants and perioperative bleeding during total hip arthroplasty--a cohort study.

In vitro studies have shown that selective serotonin reuptake inhibitors inhibit platelet aggregation. It is well documented that SSRIs cause serious gastrointestinal bleeding, but studies on other bleeding manifestations have been equivocal. Our objective was to determine a possible association between use of serotonergic antidepressants (SA) and perioperative bleeding during hip replacements. We conducted a retrospective study between 1 January 2007 and 30 June 2012 among patients that underwent a primary unilateral uncemented total hip arthroplasty (THA). Information was collected on the observed blood loss and the need for blood transfusions among this group. We compared the blood loss between users of SA, users of non-serotonergic antidepressants (NSA) and non-users, while adjusting for potential confounders using multivariate linear regression. We indentified 1318 patients that underwent a THA in the study period. The average volume of surgical bleeding was 350 ml. The adjusted incremental blood loss associated with use of SA and NSA was 93, 95% confidence interval (38-147) ml and -50 (-125 to 25) ml compared with non-use. Only 48 subjects (3.6%) had transfusions. Use of SA was associated with an increased blood loss compared with non-users. The hypothesis that SA impairs haemostasis is supported by these results.