These common drugs may increase dementia risk

A growing body of evidence indicates that routine medications can affect brain health. In particular, drugs with strong anticholinergic effects have been repeatedly associated with increased dementia risk. Anticholinergic drugs block acetylcholine, a brain neurotransmitter important for memory. Many widely used medications fall into this class, including treatments for overactive bladder (oxybutynin, solifenacin), Parkinson’s disease (benztropine), some antidepressants (amitriptyline, doxepin), antipsychotics and older antihistamines (diphenhydramine). In one large UK study, patients with the highest cumulative anticholinergic use had up to 49% higher odds of developing dementia than non-users. Even people with moderate exposure showed small but significant increases in risk. The researchers concluded that “exposure to several strong anticholinergic medications is associated with an increased risk of dementia, highlighting the importance of reducing use of these drugs”.

• Anticholinergic medications: Drugs used for bladder control, depression and allergies fall here. For example, oxybutynin (for overactive bladder) or amitriptyline (an antidepressant) each block acetylcholine. A UK analysis found that heavy use of these drugs (over years) raised dementia risk significantly. Even relatively common exposure (e.g. taking one such pill daily) may modestly raise risk. Doctors now try to use non-anticholinergic alternatives (like mirabegron instead of oxybutynin) in older patients.
• Sleep/anxiety drugs: Benzodiazepines and “Z-drugs” (e.g. lorazepam, temazepam, zolpidem) have been suspected to cause dementia in long-term users. However, large population studies paint a mixed picture bmcmedicine.biomedcentral.com. For instance, a French cohort of 1.2 million people found no overall increase in dementia rates among benzo users versus non-users (adjusted hazard ratio ~1.06, not statistically significant) bmcmedicine.biomedcentral.com. Only patients using very high cumulative doses (much more than typical) showed any small elevated risk. Interestingly, current high-dose benzo use was linked to subtle brain changes on MRI: lower hippocampal volume and faster hippocampal decline, hinting at possible cognitive effects even if overt dementia rates weren’t up. In practice, physicians advise using the lowest effective dose of sedatives and for the shortest time needed.
• Opioid painkillers: Chronic opioid therapy has also been studied. A recent Korean population study (1.2 million subjects) found that long-term opioid users had about a 15% higher risk of developing dementia compared to non-users. The excess risk was seen for Alzheimer’s dementia and other unspecified dementias. (This does not prove opioids cause dementia, but it does suggest caution and regular review of patients on opioids for many years.)
• Other medications: Early reports linked proton pump inhibitors (PPIs, for acid reflux/heartburn) to dementia risk, raising alarm among seniors taking omeprazole and similar drugs. However, newer genetic analyses (Mendelian randomization studies) have found no robust evidence that PPI use causes dementia. In other words, the apparent risk in some observational studies may reflect other factors, and experts currently do not advise stopping PPIs solely out of dementia fears. Nonetheless, it’s wise to only take PPIs or other chronic drugs when medically necessary.

Patients concerned about memory should never stop essential medicines on their own. But they should have regular medication reviews with their doctor, especially in older age. For high-risk drugs (e.g. anticholinergics), alternatives or dose reductions can often be tried. In fact, clinical guidelines now recommend minimizing anticholinergic burden in the elderly. One UK report stresses that “strong anticholinergic medications…should be reduced if possible” to help preserve cognition. In short, the evidence suggests that choice of drug matters in midlife and beyond – some pills are more likely than others to accelerate cognitive decline.

Research on this topic is evolving. Patients should discuss risks with their doctors. For example, an older adult on oxybutynin and diphenhydramine might switch to lifestyle bladder measures and a non-drowsy allergy pill. As always, benefits of treatment (e.g. relieving insomnia or pain) must be balanced against possible long-term risks. But awareness of these associations is key: it encourages us to review prescriptions in seniors, deprescribe unnecessary medications, and favor safer alternatives whenever possible.