Medications for attention deficit/hyperactivity disorder (ADHD)approved based on clinical trials that were not designed to study their long-term efficacy and safety or to detect rare adverse events, researchers at Boston Children's Hospital report
According to the U.S. Centers for Disease Control and Prevention, 11 percent of children in the U.S. between the ages of four and 17 - or about 6.4 million children - have been diagnosed with ADHD. On average, children prescribed ADHD medications take them for several years.
To understand how extensively the long-term safety of common ADHD medications had been studied before going on the market, the researchers reviewed the clinical trial data included in the FDA drug approval packages for 20 drugs, reaching as far back as the original FDA approval for methylphenidate (Ritalin®) in 1955.
The team identified 32 clinical trials on the 20 drugs. Only five trials were focused specifically on drug safety. The team calculated that each drug was tested in a median of 75 patients prior to FDA approval, with a median trial duration of four weeks. Eleven of the 20 drugs were approved after having been tested in fewer than 100 patients, and 14 in fewer than 300. Seven drugs that the FDA had previously approved for other conditions (e.g., obesity) were approved for ADHD without any condition-specific trials or trials in children.