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Researchers say amlodipine could serve as a safer option for patients without the risks that many other drugs carry
In a nutshell
- Common blood pressure medication amlodipine shows promise in treating ADHD symptoms like hyperactivity and impulsivity in multiple studies across different species
- The drug works differently than current ADHD medications and could help the 25% of patients who don’t respond to existing treatments
- Since amlodipine is already FDA-approved with a well-known safety profile, it could potentially become available as an ADHD treatment option more quickly than newly developed drugs
SURREY, England — A widely used blood pressure medication could offer new hope for people with ADHD, according to research. The drug, called amlodipine, reduced hyperactivity and impulsivity in multiple studies, suggesting it might one day serve as an alternative treatment for a condition that affects millions worldwide.
ADHD (Attention-Deficit/Hyperactivity Disorder) impacts about 11% of children and 6% of adults in the U.S., according to CDC data. The condition creates significant challenges in daily life through difficulties with attention, impulse control, and hyperactive behavior. While current treatments help many patients, they often come with concerning downsides. Standard ADHD medications can decrease appetite, disturb sleep, cause headaches, and carry risks of abuse. Most troublingly, these medications don’t work for about one in four patients.
Researchers from Iceland, Germany, and the UK investigated whether amlodipine could help address these treatment gaps. Their findings, published in the journal Neuropsychopharmacology, reveal promising results across multiple species and research approaches.
Research teams first tested amlodipine in rats, measuring its effects on hyperactive behavior. Female rats treated with amlodipine showed significant reductions in hyperactivity, while the effect in male rats was less pronounced and only became statistically significant when both sexes were analyzed together.
Parallel studies in zebrafish yielded even more encouraging results. Using specially bred fish that display ADHD-like behaviors, researchers found amlodipine reduced both hyperactivity and impulsivity. The fish underwent a sophisticated testing procedure that measured their ability to wait for signals before responding – similar to how humans with ADHD might struggle with waiting their turn or acting on impulse.
One crucial discovery challenged long-held beliefs about amlodipine. Scientists previously thought the drug couldn’t effectively cross the blood-brain barrier, the body’s natural defense system that prevents many substances from reaching the brain. However, this research proved otherwise. Not only does amlodipine reach the brain, but it also reduces activity in regions linked to ADHD symptoms.
Moving beyond animal studies, researchers analyzed human genetic data to understand if amlodipine’s effects might translate to people. They examined genetic variations in the proteins targeted by amlodipine and found significant links to ADHD, suggesting the drug’s mechanism could help treat the condition in humans.
Further supporting these findings, researchers examined data from the UK Biobank, a massive database containing health information from hundreds of thousands of people. They discovered that individuals taking amlodipine for blood pressure reported fewer ADHD-related symptoms, like mood swings and risk-taking behavior, compared to people taking other blood pressure medications.
Most current ADHD medications work by adjusting levels of brain chemicals like dopamine and norepinephrine. Amlodipine takes a different approach – it affects calcium channels in brain cells, which influences how these cells communicate. This unique mechanism might explain why it could potentially help people who don’t respond to traditional ADHD treatments.
“Repurposing amlodipine, a well-established blood pressure medication, offers a promising and swift pathway to address ADHD symptoms,” says study co-author Dr. Matthew Parker, from the University of Surrey, in a statement. “Our research indicates that, due to its existing approval and safety profile, amlodipine could be rapidly redeployed as a treatment option for ADHD, potentially providing relief to patients sooner than developing new medications.”
The repurposing of existing medications for new conditions offers several advantages. These drugs have already undergone extensive safety testing, their side effects are well understood, and they’re often available in generic form, making them more affordable. In amlodipine’s case, decades of use as a blood pressure medication have established its safety profile and proper dosing ranges.
Paper Summary
Methodology
Researchers employed a multi-pronged approach, starting with animal studies using both zebrafish and rats. They tested amlodipine’s effects on hyperactivity using standardized behavioral tests, including the Open Field Test for rats and the 5-Choice Serial Reaction Time Task for zebrafish. Brain penetration studies were conducted using mass spectrometry, while genetic analyses utilized data from large human databases including the UK Biobank.
Results
Amlodipine demonstrated significant effects in reducing hyperactivity in rats and both hyperactivity and impulsivity in zebrafish. The drug successfully crossed the blood-brain barrier and reduced neural activity in relevant brain regions. Human genetic analyses showed connections between amlodipine’s target proteins and ADHD, while UK Biobank data revealed reduced ADHD-like symptoms in people taking the medication.
Limitations
The research, while comprehensive, has several limitations. Animal studies may not perfectly translate to humans, and the human genetic analyses are correlational rather than directly causal. Additionally, the UK Biobank data primarily included older adults, who may not represent the typical ADHD population.
Discussion and Takeaways
This research suggests amlodipine could potentially serve as a novel ADHD treatment option, particularly valuable for patients who don’t respond to current medications. The drug’s well-established safety profile and low abuse potential make it an attractive candidate for repurposing.
Funding and Disclosures
The research was supported by various institutions including the Icelandic Technology Development Fund and European Regional Development Fund. Several authors were employees of biotechnology companies involved in the research.
Publication Information
Published in Neuropsychopharmacology, February 2025, titled “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” by Þorsteinsson et al.
