Antibiotics, antivirals, vaccinations and anti-inflammatory drugs are associated with a reduced risk of dementia, according to new research that looked at health data from more than 130 million people.
The study, led by researchers from the Universities of Cambridge and Exeter, identified several drugs already licensed and in use that have the potential to be repurposed to treat dementia.
Dementia is one of the leading causes of death in Britain and can cause profound problems for the individual and those who care for them. It is estimated that the global economic cost of this is more than $1 trillion.
Despite intensive efforts, progress in identifying medications that can delay or even prevent dementia has been disappointing. Until recently, dementia medications were only effective for symptoms and had a modest effect. Lecanemab and donanemab have recently been shown to reduce the build-up of amyloid plaques in the brain – a key feature of Alzheimer’s disease – and slow the progression of the disease, but the National Institute for Health and Care Excellence (NICE) concluded that the benefits were insufficient to warrant approval for use within the NHS.
Scientists are increasingly turning to existing drugs to see if they can be repurposed to treat dementia. Because the safety profile of these drugs is already known, the transition to clinical trials can be significantly accelerated.
We urgently need new treatments to slow, if not prevent, the progression of dementia. If we can find drugs that are already licensed for other conditions, we can get them into trials and – crucially – potentially make them available to patients much, much faster than we could for an entirely new drug. The fact that they are already available is likely to reduce costs and therefore increase the likelihood of them being approved for use by the NHS.”
Dr. Ben Underwood, Department of Psychiatry at the University of Cambridge and Cambridgeshire and Peterborough NHS Foundation Trust
This is evident from a study published today in Alzheimer’s and dementia: translational research and clinical interventionsDr. Underwood, along with Dr. Ilianna Lourida from the University of Exeter, led a systematic review of existing scientific literature to look for evidence of prescription drugs changing the risk of dementia. Systematic reviews allow researchers to bring together several studies for which the evidence is weak or even contradictory to arrive at more robust conclusions.
In total, the team examined 14 studies using large clinical datasets and medical records, collecting data from more than 130 million individuals and 1 million cases of dementia. Although they noted a lack of consistency between studies in identifying individual medications that influence dementia risk, they identified several drug classes associated with altered risk.
An unexpected finding was a link between antibiotics, antivirals and vaccines, and a reduced risk of dementia. This finding supports the hypothesis that common forms of dementia may be caused by viral or bacterial infections, and supports the recent interest in vaccines, such as the BCG vaccine against tuberculosis, and a reduced risk of dementia.
Anti-inflammatory drugs such as ibuprofen were also found to be associated with a reduced risk. Inflammation is increasingly seen to be a major contributor to a wide range of diseases, and its role in dementia is supported by the fact that some genes that increase dementia risk are part of inflammatory pathways.
The team found conflicting evidence for different classes of medications, with some blood pressure medications and antidepressants and, to a lesser extent, diabetes medications associated with a reduced risk of dementia and others associated with an increased risk.
Dr. Ilianna Lourida from the National Institute for Health and Care Research Applied Research Collaboration South West Peninsula (PenARC), University of Exeter, said: “Just because a particular drug is associated with an altered risk of dementia, this does not necessarily mean it causes or indeed helps with dementia. For example, we know that diabetes increases the risk of dementia, so anyone taking medication to control their glucose levels is of course also at a higher risk of dementia – but that doesn’t mean the medication increases your risk.
“It’s important to remember that all medications have benefits and risks. You should never change medications without discussing it with your doctor first, and you should talk to them if you have any concerns.”
The conflicting evidence may also reflect differences in the way certain studies were conducted and the way data were collected, as well as the fact that different drugs, even within the same class, often target different biological mechanisms.
The UK Government is supporting the development of a trial platform for Alzheimer’s disease to quickly and efficiently evaluate medicines, including repurposed medicines currently used for other conditions.
“Pairing together these vast sets of health data provides a single source of evidence that we can use to help us focus on which drugs to try first,” said Dr. Underwood. “We are hopeful that this means we can find some much-needed new treatments for dementia and speed up the process of getting them to patients.”
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Magazine reference:
Underwood, B.R., et al. (2025) Data-driven discovery of associations between prescription medications and dementia risk: a systematic review. Alzheimer’s and dementia Translational research and clinical interventions. doi.org/10.1002/trc2.70037.