Officials at the Food and Drug Administration and the Agency for Healthcare Research and Quality are launching a large-scale study to determine whether the medications used to treat attention-deficit hyperactivity disorder expose patients to an increased risk for cardiovascular problems.
The study is a retrospective review of about 500,000 children and adults who took ADHD medications before the end of 2005. Of the 500,000 patients included in the analysis, about 80% represent pediatric use and 20% adult use, according to the FDA. The evaluation will build on preliminary work performed by the FDA that included information from large health care databases on prescription drug use, outpatient treatment, health outcomes, and death.
The study will include all drugs being marketed for ADHD treatment and is expected to be completed in about 2 years.
Its launch follows reports of sudden death in treated patients with underlying serious heart problems, and reports of stroke and heart attack in treated adults with certain risk factors. In 2006, the agency directed ADHD drug manufacturers to revise their product labeling for physicians to include concerns about cardiovascular problems.
Earlier this year, FDA officials also directed drug manufacturers to develop patient medication guides to alert patients to possible cardiovascular risks from ADHD medications. The agency also recommended that physicians obtain a health history and assessment of possible cardiovascular problems before starting patients on ADHD medications.
The main question will be whether children with an underlying structural heart disease or an arrhythmia are at increased risk for cardiovascular problems when on these medications, said Dr. Martin T. Stein, professor of pediatrics at the University of California, San Diego. He is the recipient of unrestricted educational grants from Eli Lilly and Co., maker of Strattera, and a member of the Strattera Pediatric Advisory Board.
The 2006 reports of sudden death have raised public awareness, but the jury is still out on the risks of taking medications for ADHD. The federally funded study could lay some of these concerns to rest, he said.
But for most physicians who treat a lot of ADHD, there is no doubt about the safety of these medications, said Dr. Steven R. Pliszka, chief of the division of child and adolescent psychiatry at the University of Texas at San Antonio. Despite increases in prescriptions for these drugs among children, there has been no documented increase in cardiovascular disease, said Dr. Pliszka, who has conducted research for McNeil Pediatrics, Shire, and Eli Lilly and Co., which manufacture ADHD drugs.
ADHD affects 3%–5% of school-age children and about 4% of adults in the United States, according to estimates from the National Institute of Mental Health. Three ADHD drugs (Concerta, Strattera, and Adderall) were among the top five drugs prescribed for children 17 years and younger in 2004, according to the Agency for Healthcare and Research Quality. The national price tag for the three medications was about $1.3 billion in 2004.