An anonymous reader quotes a report from The New York Times: A new study suggests that people who take a class of common medicines called anticholinergic drugs for several years may be more likely to develop dementia as they age (Warning: source may be paywalled; alternative source). Anticholinergic drugs include the antipsychotic clozapine; the bladder drug darifenacin (marketed as Enablex); the anti-nausea drug scopolamine; the bronchodilatoripratropium; the muscle relaxant tizanidine; antihistamines such as diphenhydramine (brand names include Benadryl), and antidepressants such as paroxetine (brand names include Paxil). These medications work by blocking a chemical called acetylcholine, which acts as a neurotransmitter and is involved in many nervous system functions including muscle movements, heart rate, the widening of blood vessels, respiratory functions and muscle contractions in the stomach during digestion.
The research, conducted by Carol Coupland, a professor of medical statistics in primary care at the University of Nottingham in England, and colleagues, evaluated anticholinergic drugs prescribed to nearly 285,000 people age 55 and older. About 59,000 of them had a diagnosis of dementia. The study found a 50 percent increased risk of dementia among people who used a strong anticholinergic drug daily for about three years within that 10-year period. The association was stronger for antidepressants, bladder drugs, antipsychotics and epilepsy medications, the study said. Researchers did not find any increased risk of dementia with antihistamines, bronchodilators, muscle relaxants or medications for stomach spasms or heart arrhythmias. The link between anticholinergic drugs was stronger for people diagnosed with dementia before they turned 80 and in people with vascular dementia compared to people with Alzheimer’s disease, the authors reported.