An experimental drug for attention deficit hyperactivity disorder that works differently from stimulant medications, such as Ritalin, appears to be safe and effective, according to a study presented today at a meeting of the American Psychiatric Assn. in New Orleans.
If eventually approved for use, the medication would represent the first new class of drugs approved to treat ADHD other than stimulants, which have been used for decades.
The drug, atomoxetine, works by enhancing a neurotransmitter in the brain, norepinephrine, that is thought to control behaviors related to attention and impulsivity. The drug could become available for use within 18 to 24 months, according to Dr. David Michelson, a scientist with Eli Lilly & Co., the maker of atomoxetine.
The data being released today are from a phase-three clinical trial of about 300 patients ages 8 to 18. The results of the study are similar to previous atomoxetine trials showing that about 69% of children showed substantial improvement on the medication, contrasted with about 30% of children receiving a placebo, which is an inactive pill.
Michelson says Eli Lilly will submit an application to the Food and Drug Administration in the fall that seeks approval to market atomoxetine.
Atomoxetine is also thought to be comparable in effectiveness to stimulant medications, such as Ritalin, Adderall and Concerta, although larger clinical trials are needed to confirm that, Michelson says. But researchers say they are particularly enthusiastic about atomoxetine because it differs in several important ways.
"There are two subsets of kids this might help," says Dr. Chris Kratochvil, an assistant director of the psychopharmacology research center at the University of Nebraska Medical Center. "One is kids we've never treated before. And the other group is those kids who have tried stimulants and want an alternative."
According to Kratochvil, who participated as an investigator in the recent study, some parents decline stimulant therapy for their children because of the stigma attached to its use and safety fears.
"There are some parents who will refuse to have their children treated with stimulant medication," says Kratochvil. "It's a controlled drug, and it is abusable, and that intimidates many parents."
Moreover, about 30% of children are not helped by stimulant medications, says Kratochvil.
Stimulants are also linked with several side effects including suppressed appetite, weight loss and insomnia.
While atomoxetine also appears to cause appetite suppression, the drug does not seem to affect sleep, Michelson says.
An estimated 3% to 5% of children have ADHD, experts say. In the United States, about 6 million prescriptions for stimulants are written each year to treat the disorder, according to the National Institute of Mental Health.