New research analyzing health data from over 130 million individuals has linked antibiotics, antivirals, vaccinations, and anti-inflammatory medications to a reduced risk of dementia.
The study, led by researchers from the universities of Cambridge and Exeter, identified several existing, licensed drugs with the potential to be repurposed for dementia treatment.
Dementia is a leading cause of death in the UK, causing significant distress for both individuals and caregivers. Globally, it carries an economic burden exceeding $1 trillion. Despite extensive research efforts, progress in developing drugs to slow or prevent dementia has been limited. Until recently, available treatments only managed symptoms with modest effectiveness.
New drugs like lecanemab and donanemab have shown promise in reducing amyloid plaque buildup—a hallmark of Alzheimer’s disease—and slowing disease progression. However, the National Institute for Health and Care Excellence (NICE) determined that their benefits were insufficient for approval within the NHS.
As a result, scientists are increasingly exploring the potential of existing medications for dementia treatment. Since these drugs already have established safety profiles, repurposing them could fast-track the transition to clinical trials.
Dr Ben Underwood, from the Department of Psychiatry at the University of Cambridge and Cambridgeshire and Peterborough NHS Foundation Trust, said: “We urgently need new treatments to slow the progress of dementia, if not to prevent it. If we can find drugs that are already licensed for other conditions, then we can get them into trials and — crucially — may be able to make them available to patients much, much faster than we could do for an entirely new drug. The fact they are already available is likely to reduce cost and therefore make them more likely to be approved for use in the NHS.”
A new study published in Alzheimer’s & Dementia: Translational Research & Clinical Interventions examines the impact of prescription drugs on dementia risk. Led by Dr. Underwood and Dr. Ilianna Lourida from the University of Exeter, the study systematically reviewed existing scientific literature to identify medications that may influence dementia risk. Systematic reviews help researchers consolidate findings from multiple studies, even when individual results are weak or contradictory, to draw more reliable conclusions.
The team analyzed 14 studies utilizing large clinical datasets and medical records, encompassing data from over 130 million individuals and more than 1 million dementia cases. While results varied across studies in pinpointing specific drugs that influence dementia risk, several drug classes were consistently linked to changes in risk levels.
One unexpected finding was the association between antibiotics, antivirals, and vaccines with a reduced risk of dementia. This supports the theory that common dementias may be triggered by bacterial or viral infections and reinforces interest in vaccines—such as the BCG vaccine for tuberculosis—as potential protective factors against dementia.
The study also found that anti-inflammatory drugs, including ibuprofen, were associated with lower dementia risk. Given the growing recognition of inflammation as a major factor in numerous diseases, this aligns with evidence suggesting that some genes linked to dementia risk play a role in inflammatory pathways.
However, the team observed conflicting evidence for certain drug classes. Some blood pressure medications, antidepressants, and, to a lesser extent, diabetes medications were linked to both decreased and increased dementia risk, depending on the study.
Dr Ilianna Lourida from the National Institute for Health and Care Research Applied Research Collaboration South West Peninsula (PenARC), University of Exeter, said: “Because a particular drug is associated with an altered risk of dementia, it doesn’t necessarily mean that it causes or indeed helps in dementia. We know that diabetes increases your risk of dementia, for example, so anyone on medication to manage their glucose levels would naturally also be at a higher risk of dementia — but that doesn’t mean the drug increases your risk.
“It’s important to remember that all drugs have benefits and risks. You should never change your medicine without discussing this first with your doctor, and you should speak to them if you have any concerns.”
The inconsistencies in evidence may stem from variations in study design, data collection methods, and the fact that different drugs within the same class can target distinct biological mechanisms.
To accelerate the evaluation of potential treatments, including repurposed medications, the UK government is backing the development of an Alzheimer’s trial platform designed to test drugs quickly and efficiently.
“Pooling these massive health data sets provides one source of evidence which we can use to help us focus on which drugs we should try first,” said Dr Underwood. “We’re hopeful this will mean we can find some much-needed new treatments for dementia and speed up the process of getting them to patients.”
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