Association Between Antipsychotic Use and Risk of Acute Myocardial Infarction

BACKGROUND: Antipsychotic medications have been increasingly and more widely prescribed despite continued uncertainty about their association with the incidence of acute myocardial infarction (AMI). METHODS AND RESULTS: We investigated the risk of AMI associated with antipsychotic treatment in 56 910 patients with schizophrenia, mood disorders, or dementia first hospitalized or visiting an emergency room for AMI in 1999 to 2009. A case-crossover design was used to compare the distributions of antipsychotic exposure for the same patient across 1 to 30 and 91 to 120 days just before the AMI event. Adjustments were made for comedications and outpatient visits. The adjusted odds ratio of AMI risk was 2.52 (95% confidence interval, 2.37-2.68) for any antipsychotics, 2.32 (95% confidence interval, 2.17-2.47) for first-generation antipsychotics, and 2.74 (95% confidence interval, 2.49-3.02) for second-generation antipsychotics. The risk significantly increased (P<0.001) with elevations in dosage and in short-term use (≤30 days). Male patients, elderly patients, and patients with dementia were at significantly increased risk (all P<0.001). Physically healthier patients with no preexisting diabetes mellitus, hypertension, or dyslipidemia were at significantly greater risk (P<0.001), largely because they had been exposed to higher doses of antipsychotics (P<0.001). A study of the selected binding of antipsychotics to 14 neurotransmitter receptors revealed only dopamine type 3 receptor antagonism to be significantly associated with AMI risk (adjusted odds ratio, 2.59; 95% confidence interval, 2.43-2.75; P<0.0001). CONCLUSIONS: Antipsychotic use may be associated with a transient increase in risk for AMI, possibly mediated by dopamine type 3 receptor blockades. Further education on drug safety and research into the underlying biological mechanisms are needed.