Dementia Linked With Treatment For Chronic Lower Back Pain

A drug widely used to treat nerve pain and epilepsy has been linked with an increase in cases of dementia and mild cognitive impairment.

A team from Case Western Reserve University School of Medicine, Arizona State University, and the MetroHealth Medical Center in the US crunched the numbers on 26,416 records of patients with chronic lower back pain, looking at the relationship between prescriptions for the anticonvulsant gabapentin and dementia diagnoses.

Having six or more gabapentin prescriptions was linked to a significant increase in dementia risk and mild cognitive impairment (MCI), the data showed: those in that group were 29 percent and 85 percent more likely to be diagnosed with dementia and MCI respectively, within 10 years.

Related: Massive Study Links 15 Factors to Early Dementia Risk

The increase was higher among patients aged between 35 and 49, and also rose with the number of prescriptions given, the researchers found. Though the study can't establish a cause for the increase, physicians are encouraged to keep a close eye on patients taking the drug.

"Gabapentin prescription in adults with chronic low back pain is associated with increased risk of dementia and cognitive impairment, particularly in non-elderly adults," write the researchers in their published paper.

"Physicians should monitor cognitive outcomes in patients prescribed gabapentin."

Sold under brand names including Neurontin, gabapentin has proved to be less addictive than opioids, making it more likely to be prescribed in recent years. The drug does have some known side effects though, including extreme moods and allergic reactions.

This isn't the first time researchers have examined associations between gabapentin and dementia, but previous studies haven't agreed on whether or not concerns are warranted.

Gabapentin is a commonly prescribed medication for pain relief and epilepsy. (Gabapentin by Dominic Milton Trott, CC BY 2.0)

One of the study's strengths is the relatively large sample size of its participants, though the sample largely consisted of just one group of people – those with chronic lower back pain. A study published in 1997 found no link between gabapentin and cognitive decline in people with epilepsy, so it's important to continue to widen the data set.

These conflicting results could suggest unique mechanisms among patients with the type of backpain that leads to a gabapentin prescription that also increases their risk of dementia, like a certain type of location of inflammation.

But gabapentin works by dampening some of the brain's key communication channels, in order to provide relief from pain or make seizures less likely. So the worry is that it could also be damaging links between neurons in ways that might lead to dementia – a concern backed up by this latest study.

Dementia is a challenging condition to study with so many potential factors to account for, but each study gets us closer to the full picture of how the brain breaks down over time.

"We hope the current study promotes further research to delineate whether gabapentin plays a causal role in the development of dementia and the underlying mechanisms of this relationship," write the researchers.

The research has been published in Regional Anesthesia & Pain Medicine.