April 30, 2002
Brain imaging reveals new information about medications commonly used to treat children with autism or other pervasive developmental disorders
For the first time, researchers at the University of Washington Center for Anxiety and Depression and the Diagnostic Imaging Center have systematically measured brain levels of two common medications that are frequently prescribed for children diagnosed with autism or other pervasive developmental disorders. There has not been a systematic approach to prescribing these medications for children. Some practitioners have also argued that due to increased drug metabolism in the liver, children should be prescribed higher doses relative to their weight than for adults.
“We found that due to characteristics of brain uptake of the medications, that children and adult dosing was comparable when adjusted in relationship to weight,” said the study’s corresponding author, Dr. Stephen Dager, professor of psychiatry and behavioral sciences and of radiology and adjunct professor of bioengineering.
Fluvoxamine and fluoxetine, sold as Luvox and Prozac, are also used to treat panic, depression and obsessive/compulsive symptoms in adults. The study by Dager and his colleagues is one of several related imaging studies featured as the cover articles in the May issue of the American Journal of Psychiatry. The journal issue’s theme is recent advances in brain imaging.
“We specifically examined the relationship between age and brain levels of these commonly prescribed psychotropic medications,” Dager said. “Brain levels of some drugs can now be non-invasively measured in children, but up to now, this has not been used to figure out optimal dosing strategies. It seemed like a good thing to do, given that Prozac and Luvox are increasingly being prescribed to young children with autism, as well as children with other neuropsychiatric disorders. It makes sense that physicians should be better informed when they prescribe these medications for children.”
The study compared brain levels of the two medications prescribed to 28 adults and 16 children between 6 and 15 years old using fluorine magnetic resonance spectroscopy.
“Using a clinical MRI scanner and some specially built equipment, we were able to measure the signals from the fluorine atoms in the Prozac and Luvox and quantitate the brain levels,” Dager said. “We systematically evaluated kids being treated for autism disorder and other similar pervasive developmental disorders in the autism spectrum who were being treated with one of these medications and compared how their brain levels of these drugs corresponded to adult levels. If you adjusted the dose in relationship to body mass between the two groups, brain levels in the kids were very similar to adult levels.”
The adults who participated in the study were not autistic. They were being treated at the Center for Anxiety and Depression for obsessive compulsive disorder, panic disorder or major depression and being medicated with either Prozac or Luvox.
Autism symptoms can include repetitive or compulsive behavior, impaired social interaction and abnormal language development. These symptoms typically appear in early childhood and are life-long, although Dager and other researchers hope that early treatment intervention with Prozac, Luvox or other medications may prevent some symptom development and lessen the severity of this debilitating illness.
“More work needs to be done investigating brain uptake and concentration of these drugs in other pediatric populations to see just how much our findings can be generalized,” Dager said. “We can’t at this point address whether specific brain chemical and anatomical differences we have observed in younger children with autism might be affecting the brain uptake and concentration of these drugs in the small group of children studied to date.”
