WASHINGTON (AP) _ Federal health advisers considered on Thursday whether warning labels might be needed on drugs for attention deficit hyperactivity disorder following the deaths of 25 people taking the increasingly popular medicines.
Analysis of reports of death and injury suggests a possible link between the drugs and cardiovascular problems, said Dr. Kate Gelperin of the Food and Drug Administration. But she told an FDA advisory panel that the link is not conclusive, nor is it clear whether there is an increased incidence of death or serious injury among people treated with the drugs.
That, Gelperin said, ``is really a question we'd like to have answered.''
The deaths occurred between 1999 and 2003, according to FDA staff. Nineteen involved children. The report also detailed 54 cases of serious cardiovascular problems, including heart attack, stroke, hypertension, palpitations and arrhythmia, in adults and children being treated with ADHD drugs.
Some of these ADHD drug-treated patients had pre-existing heart conditions or hypertension. That could lead to a new warning on the labels on the drugs, the FDA said.
The drugs include amphetamines, such as Adderall, and methylphenidates, sold as Ritalin, Concerta, Methylin and Metadate.
The FDA said it has tallied an additional 26 deaths between 1969 and 2003 in ADHD patients involving death by suicide, intentional overdose, drowning, heat stroke and from underlying disease.
The FDA's Drug Safety and Risk Management advisory committee is considering how best to study whether the deaths and injuries are linked to use of the drugs, as well as specific ways of conducting such studies. The few studies that have looked at longer-term use of ADHD drugs provide little information on those risks, the FDA said.
Sen. Chuck Grassley, R-Iowa, criticized the FDA's pace in studying the issue earlier this week.
In a letter sent Monday to acting FDA commissioner Dr. Andrew von Eschenbach, Grassley said in part, ``I remain concerned that while both psychiatric and cardiovascular risk signals have cropped up across this class of drugs this past year, it appears that FDA is just now beginning to 'discuss approaches' for studying these risks.''
An FDA review found fewer than one case of death or serious injury per 1 million ADHD drug prescriptions filled, with one exception: 1.79 cases per million of nonfatal cardiovascular or cerebrovascular problems in adults treated with amphetamines.
Currently, about two million children and one million adults are prescribed ADHD drugs each month, the FDA's Dr. Andrew Mosholder said. Adult use alone grew 90 percent between March 2002 and June 2005, he said.
Sales of ADHD drugs increased to $3.1 billion in 2004, from $759 million in 2000, according to IMS Health, a pharmaceutical information and consulting firm.
The FDA's Canadian equivalent, Health Canada, briefly pulled the ADHD drug Adderall XR from the market last year. A Canadian panel eventually concluded there was inadequate evidence of increased harm from the drug. The FDA reached a similar conclusion at the time.
Adderall is made by Shire Pharmaceuticals and Ritalin is made by Novartis Pharmaceuticals Corp. Various other companies make generic versions of Ritalin as well.