Dementia ‘linked’ to common overthecounter drugs

Posted 27/01/2015

The BBC reported today that a study has linked commonly used medicines, including over-the-counter treatments for conditions such as insomnia and hay-fever, to dementia.

All of the types of medication in question are drugs that have an “anticholinergic” effect. Experts say people should not panic or stop taking their medicines. In the US study in the journal JAMA Internal Medicine, higher doses and prolonged use were linked to higher dementia risk in elderly people.

Researchers say people should be aware that anticholinergic-type drugs may be linked to a higher risk of developing dementia.

Staff at the University of Washington followed the health of 3,434 people aged 65 and older who had no signs of dementia at the start of the study. They looked at medical and pharmacy records to determine how many of the people had been given a drug with an anticholinergic effect, at what dose and how often and compared this data with subsequent dementia diagnoses over the next decade.

The most commonly used anticholinergic-type drugs were medicines for treating depression, antihistamines for allergies such as hay-fever or to aid sleep/promote drowsiness, and drugs to treat urinary incontinence. Nearly a fifth were drugs that had been bought over the counter. Over the course of the study, 797 of the participants developed dementia.

The study estimated that people taking at least 10 mg/day of doxepin (antidepressant), four mg/day of diphenhydramine (a sleep aid), or five mg/day of oxybutynin (a urinary incontinence drug) for more than three years would be at greater risk of developing dementia.

The researchers say doctors and pharmacists might want to take a precautionary approach and offer different treatments instead. When there is no alternative, they could give the lowest dose for the shortest time possible.

Dr Simon Ridley, head of research at Alzheimer’s Research UK, said the study was interesting but not definitive. He has said that there is no evidence that these drugs cause dementia.

Sophie Bales, a medical injury solicitor at Ashtons Legal, comments:       

“This research has gone some way to linking certain types of medication with dementia. However, further studies are required to explore the connections further.

The advice at this stage appears to be for GPs and/or pharmacists to be aware of the possible link and for patients to seek their GP’s advice if they are concerned. It is obviously very important that patients do not panic at this stage and stop taking any medication without first seeking their GP’s advice.”