Blood Pressure Drug Could Be Repurposed for ADHD
Repurposing amlodipine, a common blood pressure drug, could provide a safer alternative to existing ADHD medicines.
Attention-deficit/ hyperactivity disorder (ADHD) is a neurodevelopmental condition that can lead to a range of behavioral and psychiatric challenges. Existing treatments can be associated with significant side effects including appetite loss, hypertension, headaches and sleep disturbances, as well as a risk of substance abuse. Repurposing amlodipine, a commonly used blood pressure medicine, could offer a promising new pathway to address ADHD symptoms.
In a study published in Neuropsychopharmacology, researchers found that amlodipine decreased both hyperactivity and impulsivity in a zebrafish model of ADHD. Further analysis of human genetic data found that ADHD is linked to the same calcium channels in the brain that are targeted by amlodipine. These findings highlight the potential of refining and developing the drug into a novel treatment for ADHD.
Repurposing drugs for ADHD
Current treatments for ADHD often involve stimulants such as methylphenidate and amphetamines. “They work well for many people, but they also have some serious side effects, like losing your appetite, having trouble sleeping, your heart beating faster and even becoming addicted,” Dr. Matt Parker, associate professor of neuroscience and behavioral analysis at the University of Surrey, told Technology Networks.
Other treatment options include non-stimulant drugs such as atomoxetine and guanfacine. “These drugs have fewer risks of abuse, but they’re not as effective and can cause fatigue, sleep problems, stomach issues (like constipation) and mood swings,” explained Parker.
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Subscribe for FREEIn addition to the numerous side effects associated with current ADHD treatments, an estimated 25% of ADHD patients don’t respond to existing medications. These issues are compounded by current supply chain issues. “There are shortages of ADHD drugs, especially in the UK and the US. This is causing problems with treatment, as you can see from reports from the UK NHS and US FDA throughout 2024 (there are dozens of them!),” Parker said.
In efforts to find new treatments, the researchers previously tested over 1,200 existing drugs to see if any could help improve ADHD symptoms in zebrafish that had been genetically engineered to show ADHD-like traits.
“We checked if known ADHD drugs worked on them first (which they did), then tested the new compounds to see if they could reduce hyperactivity,” said Parker. “After narrowing down the best options, we tested them in adult fish that showed other ADHD-like behavior (impulsivity), and then in rats to make sure the effects weren’t just limited to fish.”
“In the end, we narrowed our search down to five promising drugs – this included amlodipine, a blood pressure medication – that might work as new ADHD treatments. Because these are already approved for other conditions, they could be repurposed faster than developing brand-new medications!”
In the current study, the researchers tested the five promising drugs in rodents and zebrafish. Only amlodipine significantly reduced hyperactivity in the rodent assay.
Zebrafish as a model for human disease
To confirm amlodipine effects, the team tested it on zebrafish. “Zebrafish have several very cool advantages over mammals. First, young zebrafish (called larvae) are transparent, so we can watch their brains work under a microscope in real-time (which is unique in vertebrate animal models). The females also lay lots of eggs at once, which lets us study how drugs affect a lot of different things at the same time (we call this ‘high-throughput testing’),” Parker explained.
“Another fantastic advantage is that zebrafish studies – particularly in the larvae – are considered more ethical than traditional animal models. They don’t get as stressed out as the adults [adult zebrafish], and don’t need as many resources provided (complexity in the environment, etc.,).”
There are also some disadvantages to using zebrafish. “Zebrafish brains aren’t exactly the same as human brains, so we need to ensure our findings also work in humans. This is the reason we also do rat studies, but doing the fish first means that we can study the rats in far smaller numbers than if we had only used rats,” Parker stated.
A novel therapeutic approach to ADHD
The current study shows that amlodipine reduces both hyperactivity and impulsivity in zebrafish. The researchers also found that amlodipine was able to cross the blood–brain barrier to have a direct influence on brain function.
Performing genetic analyses, the researchers identified a link between ADHD and genetic variations in L-type calcium channel subunits targeted by amlodipine. This brain pathway presents a potential target for new treatments. Furthermore, analysis of UK-wide patient data showed fewer reported mood swings and risk-taking behaviors by people taking amlodipine. Collectively, the findings further support amlodipine’s potential to be repurposed as a new ADHD treatment.
“Because amlodipine is already a widely used and well-understood drug, this means the process can move much faster than developing a brand-new medication from scratch,” said Parker.
The next steps for this research will involve testing amlodipine in ADHD patients to confirm the effects observed in rodents and zebrafish. “3Z is currently developing a new formulation of amlodipine specifically for ADHD, with plans to run human trials soon,” explained Parker.
Beyond ADHD, Parker believes the methods utilized in this study could find application across many disease areas. He concluded, “We are already using this approach to explore a range of other areas, including developing new pain medications and investigating treatments for other psychiatric conditions. The only real limitation is what we can effectively study in young zebrafish, but we are putting a lot of effort into understanding their behavior in more detail.”
Reference: Þorsteinsson H, Baukmann HA, Sveinsdóttir HS, et al. Validation of L-type calcium channel blocker amlodipine as a novel ADHD treatment through cross-species analysis, drug-target Mendelian randomization, and clinical evidence from medical records. NPP. 2025. doi: 10.1038/s41386-025-02062-x
About the interviewee
Dr. Matt Parker is an associate professor of neuroscience and behavioral analysis at the University of Surrey, and a Royal Society Short Industry Fellow. Parker completed a BSc, MSc and PhD at the University of Southampton, followed by postdoctoral fellowships at the Royal Veterinary College and Queen Mary University of London. Parker then became a lecturer in cell biology and developmental genetics at Queen Mary, where he also taught at Nanchang Medical School (China). From 2015 to 2022, he was based at the University of Portsmouth, where he founded the Brain and Behaviour Lab and established the Portsmouth zebrafish facility.
In 2022, Parker joined the University of Surrey as a senior lecturer in neuroscience. The Parker group uses precision approaches to uncover the biological mechanisms underlying neuropsychiatric, neurodevelopmental and neurodegenerative conditions, combining experimental psychopharmacology, molecular genetics and computational analysis to develop targeted interventions.
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