ADHD drugs appear to present no cardiovascular risks in adults

Attention-deficit/hyperactivity disorder (ADHD) medications were not associated with an increased risk of serious cardiovascular events among young and middle-aged adults, researchers found.

Researchers conducted a retrospective, population-based cohort study using electronic health care records from four study sites from 1986 through 2005, with additional covariate assessment using 2007 survey data. Participants were 25 through 64 years of age with dispensed prescriptions for methylphenidate (45% of current use), amphetamine (44%), atomoxetine (8%), and pemoline (3%). Each medication user (n=150,359) was matched to two nonusers by study site, birth year, sex and calendar year. Results appeared in the Dec. 14 Journal of the American Medical Association.

There was no evidence of an increased risk of serious cardiovascular events, including myocardial infarction (MI), sudden cardiac death (SCD), or stroke, associated with current use compared with nonuse or past use of ADHD medications. There was also no increased risk found with any specific medication or with longer duration of use. Results were similar when the study population was restricted to new users.

During 806,182 person-years of follow-up (median, 1.3 years per person), 1,357 cases of MI, 296 cases of SCD and 575 cases of stroke occurred. There were 107,322 person-years of current use (median, 0.33 year), with a crude incidence per 1,000 person-years of 1.34 (95% CI, 1.14 to 1.57) for MI, 0.30 (95% CI, 0.20 to 0.42) for SCD, and 0.56 (95% CI, 0.43 to 0.72) for stroke.

The multivariable-adjusted rate ratio (RR) of serious cardiovascular events for current use compared to nonuse of ADHD medications was 0.83 (95% CI, 0.72 to 0.96). Among new users of ADHD medications, the adjusted RR was 0.77 (95% CI, 0.63 to 0.94). The adjusted RR for events among current users compared to those whose prescriptions ended more than one year prior was 1.03 (95% CI, 0.86 to 1.24). For new users compared to those whose prescriptions ended more than one year prior, the adjusted RR was 1.02 (95% CI, 0.82 to 1.28).

An editorialist commented, “Perhaps the greatest clinical influence of [the study] will be in how clinicians counsel patients regarding the risks and benefits of ADHD medications. Now there is solid evidence—perhaps even some heartening news—that physicians can use to address concerns about cardiovascular risk.”