Antipsychotic drugs as a risk factor for venous thromboembolism

Objective. We assessed whether antipsychotic drugs represent a risk factor for venous thromboembolism by comparing the prevalence of antipsychotic drugs use in a population of patients with venous thromboembolism versus a group of individuals treated for hypertension. Methods. We identified 266 patients ( 141 women) diagnosed as having venous thromboembolism at the average age of 43.1 +/- 11 years who had been hospitalized in the University Hospital in Hradec Kralove from 1 January 1996 to 31 December 2004. Two hundred and seventy-four patients ( 140 women) with arterial hypertension, with an average age of 48.3 +/- 8.8 years, represented the control population. Results. Use of antipsychotic drugs was moderately more frequent in the group of patients with venous thromboembolism as compared with the control group subjects (4.89 vs. 1.82%; odds ratio 2.76; 95% confidence interval = 1.01 -7.55). Discussion. We discuss the possible mechanisms of venous thromboembolism induced by antipsychotic agents - hypoactivity, blood status, obesity, abnormal coagulation, autoimmune mechanisms, and hyperhomocysteinemia. Conclusion. Our results indicate the possibility of an increased risk for venous thromboembolism in patients using antipsychotic drugs. It is necessary to seriously consider this possible adverse effect owing to its potentially fatal consequences.