Haloperidol Does Not Activate Thrombogenic Factors in Older, Nonpsychotic Hospitalized Patients

To the Editors:W orldwide, haloperidol is the antipsy- chotic drug used most often to treat delirium in (older) patients admitted to hospital. 1 In 2005, the Food and Drug Administration issued a warning about the increased mortality rate in elderly users of antipsychotics. 2Although the pathophysiological mechanism is unknown, the increased death rate might be due to vascular problems.For example, users of antipsychotic drugs are at increased risk of cerebrovascular accidents 3 and venous thromboembolism. 4,5Potential mechanisms for the association between antipsychotics and cerebrovascular events include thromboembolic effects, altered platelet function, cardiovascular effects, and the atherosclerotic effects of metabolic dysregulation. 3 Markers of thrombogenesis are activated in untreated patients with an acute psychosis, 6 which suggests that the psychosis itself may be responsible for the increased risk of morbidity and mortality.However, there is no clear explanation for the increased mortality seen in nonpsychotic elderly patients with dementia.The main aim of this study was to investigate whether factors of thrombogenesis are activated in older, nonpsychotic hospitalized patients treated with haloperidol.