Experts Note Need for More Studies on ADHD Drug Use in Adults
Most research on safety issues has been conducted in children, they note
THURSDAY, March 23, 2006 (HealthDay News) -- While experts applauded a federal panel's recommendation Wednesday to avoid the strongest warning for drugs that treat attention-deficit hyperactivity disorder, official remarks made later about the critical need for research into the cardiac effects of these stimulants on adults also struck a chord.
"Longitudinal studies so far have shown in adults minimal changes in blood pressure and pulse, but we need longer-term prospective studies to further document the safety and efficacy of these medications," said Dr. Lenard Adler, director of the adult ADHD Program at New York University Medical Center, and author of the forthcoming Scattered Minds: Help and Hope for Adults with ADHD. "Adults are going to stay on these medications for a long period of time, and adults themselves have a baseline risk of hypertension," he said.
Adults also represent a rapidly growing proportion of ADHD medication users.
According to a recent survey by Medco, the number of younger adults (aged 20 to 44) using ADHD medication skyrocketed more than 139 percent from 2000 to 2005, exceeding increases in children aged 19 and younger by 82 percent.
Roughly 2.5 million children and 1.5 million adults now take ADHD medications. And some experts, including Adler, believe the condition is undertreated.
When the U.S. Food and Drug Administration's pediatric advisory committee met Wednesday to consider whether ADHD drugs should carry additional labeling information, and possibly a black box warning, it looked at the possible risks of psychosis, mania and cardiovascular problems.
Under consideration had been all marketed drugs for ADHD, including amphetamines (Adderall XR), methylphenidates (Ritalin, Concerta and Metadate) and the non-stimulant Strattera, along with Sparlon, a narcolepsy drug being considered as a treatment for ADHD.
On Thursday, a separate FDA advisory committee voted not to recommend FDA approval of Sparlon (modafinil) for the treatment of ADHD in children and teens. The panel -- the psychopharmacologic drugs advisory committee -- voted unanimously that manufacturer Cephalon Inc. collect additional data to support the safety of using the drug in young patients, according to published reports.
At day's end Wednesday, the pediatrics committee reached a consensus that the ADHD drugs not carry a black box warning but use simpler language and include more information on the label. Just last month, a different FDA advisory committee called for a black box warning about the cardiac risks that ADHD drugs carry. The FDA is not required to follow committees' recommendations, but it usually does.
"It was a realistic recommendation," Dr. Karen Ballaban-Gil, a professor of clinical neurology and clinical pediatrics at Albert Einstein College of Medicine in New York City, said of Wednesday's action. "A black box warning is a little too aggressive, but clearer labeling is always a good thing."
But in announcing the decision Wednesday evening at a press conference, Dr. Robert Temple, director of the FDA's Center for Drug Evaluation and Research, raised the likelihood of continued analysis of risks in adults.
"We still have to come to grips with some of the recommendations made at the drug safety committee one-and-a-half months ago, but that pertained mostly to adults," Temple said. "It was quite a satisfactory meeting that answered many of our questions, but we still have much work to do on adults."
"I think they were referring to the fact that adults, depending on their age, are more likely to have underlying cardiac disease, and therefore the cardiovascular risk may be greater," Ballaban-Gil said. "I think it's a low risk, but it's not a zero risk."
The necessary data to evaluate these risks is just not out there, experts noted.
"This speaks to the need for longer-term prospective studies in the adult population because we have more longitudinal studies in kids than in adults," Adler said.
In the absence of definitive research, Adler monitors his adults patients carefully, including regular monitoring of pulse and blood pressure. "I think that's going to be the standard of care," he said.
As for children, any new labeling that is mandated is only likely to help treatment, some said.
"Making parents and patients more aware of the risks is not necessarily going to be detrimental to their use," Ballaban-Gil said. "It will just make them more aware and it may even be beneficial because some parents don't understand why doctors want you to come back for follow-up."
"The reason," she continued, "is because there are potential risks and we need to make sure there aren't any complications. This may make people understand the real need for follow-up when people are on these medications."
The National Institute of Mental Health has more on attention-deficit hyperactivity disorder.