Propranolol for Behavior Challenges: Not Yet Ready for Widespread Use
Posted by Autism Treatment Network Medical Director Dan Coury, MD
Considerable community and scientific interest has been raised by recent reports that the beta-blocker propranolol improved word use in adolescents and adults with autism spectrum disorder (ASD). It is important to emphasize that this small study does not provide sufficient evidence of effectiveness or safety to support this use of the drug, which is FDA approved to treat high blood pressure. Although we share excitement in seeing medicines evaluated in bona fide clinical studies, families should be strongly cautioned against over-interpreting media reports as endorsement to pursue this treatment for their loved ones–until larger studies show it is safe and effective.
First and foremost, treatment of autism spectrum disorders (ASDs) should include a combination of behavioral and educational interventions. Many children, adolescents, and adults with ASDs also need treatment of associated medical or psychiatric conditions such as gastrointestinal disorders, asthma, anxiety, and symptoms of attention deficit and hyperactivity disorder (ADHD).
While we have strong evidence that our behavioral treatments provide benefit, we need more research on identifying medicines that can help relieve the core symptoms of ASDs and associated behavior challenges. Interest in propranolol began over 20 years ago, with a small study (involving eight adults with autism) that suggested the drug could reduce problematic aggression. In addition, the researchers noted subtle improvements in language and social behavior. They wondered whether this might be related to the known ability of beta-blockers to reduce the symptoms of so-called overarousal. For instance, some musicians and public speakers will take a beta-blocker immediately before a performance to reduce shakiness from stage anxiety.
The authors of that first study called for further research. And the gauntlet was picked up by David Beversdorf, MD, and his associates at the University of Missouri, one of Autism Speaks Autism Treatment Network (ATN) sites. Their latest report enrolled 14 high functioning teens and adults with autism, all of whom used spoken language. They found that, when taking the medicine, some of the individuals used more words over a given period of time. That is, they had greater “word fluency.” On average, the participants showed 25 percent greater word fluency. However, some of the participants spoke fewer words while taking the medication.
What does this mean? These early studies are too small and too limited in their evidence of benefit for us to recommend that adolescents and adults with ASD begin taking this medicine. We know even less about the safety and effectiveness of beta-blocker medications in younger children. As the authors state, further study is needed to confirm both safety and benefits among a wide range of persons with ASD. And if these benefits are confirmed, we need to find ways to identify which people will respond positively to the medication and which will not. Certainly this is not a medication we want to be administering to everyone on the autism spectrum.
These early studies encourage us to pursue further research with propranolol, as we are doing with an increasing number of other medicines that could potentially help relieve the core symptoms of autism–including repetitive behaviors and impaired communication and social behavior. This exciting and encouraging research includes our study of the biological effects and behavioral benefits of both already approved medications and newly developed compounds.
Meanwhile, we have two FDA-approved medications for treating autism-related irritability that includes aggressive behavior and tantrums. They are risperidone and aripiprazole, both of which influence brain levels of the biochemical serotonin. Newer studies are looking at alternative medicines that affect other brain pathways. Early animal research with these compounds has been promising, and studies are now underway in people.
Bottom line: Studies such as Dr. Beversdorf’s are helping us better understand brain function in persons with ASD. This and related studies will ultimately lead us to new treatments and better outcomes. Until then, please stay tuned.