Research published in the US journal JAMA Internal Medicine has found an association between commonly used over the counter medicines, for conditions such as insomnia and hay-fever, to dementia.
Whilst the researchers from the University of Washington only looked at people over the age of 65, who had been using such drugs every day for at least 3 years, the study has caused a high level of concern for many younger people.
The study found that the medicines which present the highest risk of dementia have an ‘anticholinergic effect’, blocking the neurotransmitter known as acetylcholine. Patient information leaflets accompanying these drugs warn of the possibility of reduced attention span and memory problems as well as a dry mouth. The drugs most commonly falling into this category are used to treat depression (Tricyclic Antidepressants), hayfever/ allergies (Antihistamines) and urinary incontinence (Antimuscarinics). People with Alzheimer’s are known to lack acetylcholine and therefore it is feared that these medications may now exacerbate or trigger the condition.
Nearly a fifth of these drugs had been bought over the counter and, during the course of the study, 797 of the 3,434 participants (23%) developed dementia.
It was suggested that 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 could present the greatest risk.
A further US study recently found that taking a daily dose of sleep aids such as Nytol could increase the risk of the elderly developing Alzheimer’s by as much as 60%.
Here in the UK, the Alzheimer’s Society is funding further research in this area to better understand the possible connections between these and other drugs on the development of dementia, cautioning that it is still unclear whether the effects are only a result of long-term use or could potentially equally result from several episodes of short-term use.
The Medicines and Healthcare Products Regulatory Agency, which monitors the safety of medicines in clinical use in the UK, has said it would review any new evidence.
In the meantime, drug company Johnson & Johnson Ltd helpfully advised that many hay-fever products sold in the UK now contain newer, second generation antihistamines, and not the type looked at in the US study.
We at the LPA Advice Company would recommend contacting your GP to discuss alternative treatments or a reduced dosage/ duration of medication for these conditions before stopping such drugs. However, if you are concerned that you may be at an increased risk in developing dementia, it is important that an early LPA is put in place to ensure your wishes in respect of health and/or financial matters are honoured should you lose the ability to make such decisions for yourself.
LPA Advice Company