Reactions 785 - 22 Jan 2000

SVenlafaxine

Clotting disorders: case reportA 47-year-old woman with early onset type I diabetes

mellitus, hypertension and hypothyroidism, developedclotting abnormalities during treatment with venlafaxine fordepression. Her hypertension was stable at 130–140mm Hgsystolic.

The woman’s hypertension had been stable at 130–140mmHg systolic; however, 1 month after the patient startedvenlafaxine 37.5mg twice daily, her hypertension worsened(up to 180–200mm Hg systolic). In addition, she noted anincreased tendency to bruise after mild trauma. Approximately2 weeks later, she had an episode of atraumatic epistaxis andrequired transfusion of 2 units of packed RBCs. Her clottingparameters were normal at this time. However, after 2.5months of venlafaxine therapy, she was hospitalised withecchymoses and hypertension. Laboratory analysis showed anincreased partial thromboplastin time of 89sec (normal 22–36)and a high antihaemophilic factor VIII, C antibody, titre of 190BU/ml. Her systolic BP was 200mm Hg.

The woman was treated empirically with desmopressin, IVimmunoglobulin and cyclophosphamide; venlafaxine wasstopped. Her concentration of factor VIII antibody decreasedover the next 4 days to 40 BU/ml. The woman remained inhospital for 1 month and her antibody titres to factor VIIIcontinued to decrease. At discharge, her partialthromboplastin time was 40 sec, her hypertension hadreturned to baseline and her ecchymoses were resolving.

Author comment: ‘Previously proposed theories suggestthat lowered vascular tone or increased time for plateletaggregation with serotonin reuptake inhibitors leads toincreased bleeding tendencies; this case demonstrates analternative autoimmmune mechanism. We wondered whethercaution should be taken when prescribing venlafaxine topatients with suspected autoimmune pathology (non-insulin-dependent diabetes mellitus and thyroid disease in this case).’Tham CJ, et al. Abnormal clotting and production of factor VIII inhibitor in apatient treated with venlafaxine. Canadian Journal of Psychiatry 44: 923-924, Nov1999 - Canada 800808198

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Reactions 22 Jan 2000 No. 7850114-9954/10/0785-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved