A widely used medication for back pain may increase the risk of developing dementia by up to 40 per cent among patients who take it regularly.
Gabapentin, also sold as Neurontin, is prescribed to nearly 800,000 people in England and was linked to cognitive decline in new research based on 20 years of patient data. The findings raise concerns about long-term use among people with chronic pain.
The drug, introduced on the NHS in the early 1990s to treat nerve pain and epilepsy, acts on gamma-aminobutyric acid (GABA) – a chemical messenger in the brain that helps calm overactive nerve cells.
Researchers from Case Western Reserve University in Ohio analysed health records from more than 26,000 US patients prescribed gabapentin for chronic low back pain between 2004 and 2024.
They found that those who received six or more prescriptions were 29 per cent more likely to be diagnosed with dementia within 10 years. For those with 12 or more prescriptions, the risk rose to 40 per cent. Regular users were also 85 per cent more likely to be diagnosed with mild cognitive impairment (MCI), which can precede dementia.
The risk appeared particularly high among certain age groups. For patients aged 35 to 49 who were prescribed gabapentin, the risk of dementia more than doubled, and the risk of MCI more than tripled. No increased risk was observed in 18 to 34-year-olds.
The study also found that patients who received 12 or more prescriptions were 65 per cent more likely to develop MCI than those who were prescribed the drug between three and 11 times.
NHS data shows 799,155 patients were prescribed gabapentin in England in 2023/24 – down from a peak of 926,071 in 2022/23. In the US, more than 8 million prescriptions are issued each year.
“Our findings indicate an association between gabapentin prescription and dementia or cognitive impairment within 10 years,” the researchers wrote. “Our results support the need for close monitoring of adult patients prescribed gabapentin to assess for potential cognitive decline.”
However, experts not involved in the research urged caution, stressing the study shows correlation, not causation.
“This study only shows an association between gabapentin prescriptions and mild cognitive impairment or dementia, so we do not know if the medication is directly causing the higher risk,” said Dr Leah Mursaleen, head of clinical research at Alzheimer’s Research UK.
“Gabapentin dosage wasn’t recorded, and there was no information on how long people were on the medication. Because this study only used health records of people with chronic pain, we cannot rule out other factors that might be influencing the findings.
“And previous studies looking at people prescribed gabapentin for other conditions like seizures didn’t show a link between the medication and higher dementia risk.”
Professor Tara Spires-Jones, director of the Centre for Discovery Brain Sciences at the University of Edinburgh and group leader at the UK Dementia Research Institute, said: “One very important factor that was not examined in this study is levels of physical activity. People with chronic pain requiring gabapentin may have been less physically active, which is a known risk factor for developing dementia.”
According to official data, five reports linking gabapentin to Alzheimer’s or dementia have been submitted to the Medicines and Healthcare products Regulatory Agency. These reports, made by patients, families or healthcare professionals, do not prove the drug was responsible and may be coincidental.
The findings follow a major study published last year that suggested nearly half of all Alzheimer’s cases could be prevented by tackling 14 lifestyle factors from early life. Researchers also identified two additional risk factors – high cholesterol and vision loss – which may account for nearly one in ten dementia cases globally.
Alzheimer’s disease, the most common form of dementia, currently affects around 982,000 people in the UK. Common early symptoms include memory loss, confusion, and difficulty with language, with symptoms typically worsening over time.
Data from Alzheimer’s Research UK shows 74,261 people in the UK died from dementia in 2022, up from 69,178 the previous year – making it the country’s leading cause of death.
Doctors advise patients not to stop taking gabapentin without medical advice. Anyone concerned about their prescriptions should speak to their GP.