Bumetanide shows promise for some children with autism, Swedish study finds
Treatment with bumetanide has in a Swedish study been shown to potentially be beneficial for some children with autism.
Autism is a disorder of brain function with symptoms that appear early in life, generally before the age of three.
Children with autism have problems with social instinct and interaction, communication, imagination and behaviour. The autistic symptoms persist into adulthood but vary in severity. Autistic traits without additional impairment are probably quite common in the general population.
Autism manifests itself in difficulties in relating to and communicating with others resulting in social difficulties. It is common with other co-occurring conditions or disorders, e.g. ADHD, intellectual disability and developmental language disorder.
A medication more commonly used to treat heart failure and high blood pressure may ease symptoms of autism in some children. The medication has been tried in many studies in many parts of the world, starting in France 15 years ago and now a study has been carried out by researchers at the Gillberg Neuropsychiatry Centre, at the University of Gothenburg.
The drug, called bumetanide, is a diuretic or “water pill” that helps the body remove excess fluid. But scientists have long suspected that it may also have effects on the excitatory/inhibitory transmitter systems in the brain. The new study, published in the journal Acta Paediatrica, tested this idea in a group of 15 children with autism aged 4–12.
Why bumetanide?
Autism is a highly varied condition, marked by difficulties in communication, social interaction, and often accompanied by other disorders, such as intellectual disability and/or ADHD. While behavioural therapies exist, there are currently no medications that directly address the core symptoms of autism.
Bumetanide caught researchers’ attention because of how it affects chloride levels in brain cells. Chloride is linked to how the brain’s inhibitory chemical messenger, GABA, works. In early brain development, GABA can be “too excitatory,” and in some children with autism, that balance between excitation and inhibition may remain disrupted. By lowering chloride inside brain cells, bumetanide may restore GABA’s calming effect — and with it, improve social and communication skills.
The Swedish trial
The team at the Gillberg Neuropsychiatry Centre, University of Gothenburg, enrolled 15 children, age 4-12 years. Some started bumetanide right away, while others waited three months before beginning — a setup known as a “waitlist-control” design. Parents rated their children’s behaviour and communication at different stages over the nine-month trial. The results showed that:
- 2 children stopped within weeks due to worsening hyperactivity
- 4 more discontinued later on
- 9 completed the study
Of those nine, four showed clear improvements in areas like social responsiveness and communication. Parents noticed that these children made more attempts to talk, were clearer in their speech, or initiated interactions more often. For these families, the changes were meaningful enough that they chose to continue bumetanide after the trial ended.
Other children showed little or no improvement, and in some cases, results were mixed. Only one child required potassium supplements, a common precaution with diuretics.
What this means
Although the study was small, the findings echo earlier work in France, China, and the Netherlands that also reported benefits for some — but not all — children with autism. Large-scale trials have produced mixed results, with some failing to show significant improvement overall.
The Gothenburg researchers argue that the key may lie in identifying which subgroups of children are most likely to benefit. Brain scans and EEG studies in other projects suggest that certain “signatures” of brain activity could predict responsiveness to the drug.
Lead researcher, Professor and neuropaediatrician Elisabeth Fernell, stressed that bumetanide is not a cure for autism, but could be a valuable option:
“Even if only 25–30% of children benefit, that still represents a meaningful step forward for families, especially given the lack of alternatives."
The bigger picture
Scientists are exploring bumetanide’s potential in conditions like Down syndrome, Fragile X syndrome, Parkinson’s disease, and Alzheimer’s disease, all of which may share similar disruptions in brain signalling.
For now, the Swedish study adds cautious optimism: a decades-old water pill may hold new promise for easing the daily struggles of some children with autism.
The research was funded by the Swedish Brain Foundation.
Text written by Anna Spyrou Communications Officer
