Excess risk of myocardial infarction in patients treated with antidepressant medications: association with use of tricyclic agents

Abstract

PURPOSE: Several studies have found that depression and the use of antidepressant medications are associated with an increased risk of cardiovascular disease. We assessed the association between the use of antidepressant drugs and myocardial infarction, and whether that association differs between the tricyclic and selective serotonin reuptake inhibitor (SSRI) classes of medication. PARTICIPANTS AND METHODS: We compared the experience of a cohort of 2,247 working, union health plan members who received at least one prescription for an antidepressant in an accrual period of 1991–1992 with that of 52,750 members who did not. Patients were followed for up to 4.5 years (minimum 6 months). Three antidepressant medication classes were defined: tricyclics, SSRIs, and others. The primary outcome was hospitalization or death due to myocardial infarction. RESULTS: Adjusted for age and sex, antidepressant users had a relative risk of myocardial infarction of 2.2 (95% confidence interval [CI] 1.3 to 3.7) compared with nonusers of antidepressants. There were 16 myocardial infarctions among 1,650 users of tricyclic antidepressants, 2 among 655 SSRI users, and none among 279 users of other antidepressants. Adjusting for age, gender, baseline heart disease, diabetes, hypertension, hyperlipidemia, anxiety, and cancer, the relative risk of myocardial infarction was 2.2 (95% CI 1.2 to 3.8) in users of tricyclic agents and 0.8 (95% CI 0.2 to 3.5) in users of SSRIs, as compared with subjects who did not use antidepressants. CONCLUSION: The association between use of tricyclic antidepressants, but not SSRIs, with an increased risk of myocardial infarction in our patients suggests that an earlier report that there is no difference in risk between the antidepressant classes, based on short-term studies, may not apply to long-term adverse cardiovascular outcomes.