- New study suggests link between widely-prescribed anti-depressants and dementia. Medicines used to treat Parkinson’s and bladder conditions also implicated
- Growth of ‘polypharmacy’ – the use of multiple medications by individual patients – may be a factor that increases the risks
- Experts say doctors, pharmacists and nurses should re-assess whether risks of using some medicines outweigh the benefits for patients on multiple medications
Clinicians should consider ‘de-prescribing’ some drugs in the light of new research linking certain anti-depressants to dementia, according to academic pharmacists and doctors.
The latest research, funded by the Alzheimer’s Society, published today in the BMJ, suggests long-term consumption of widely-used anti-depressants with significant anti-cholinergic activity is associated with an increased risk of dementia. The study also found that overall anti-cholinergic burden was associated with dementia.
Dr Ian Maidment, Senior Lecturer in Clinical Pharmacy at Aston University and lead pharmacist on the study, highlighted the rising number of people being prescribed multiple drugs as a factor. He said: “There are two issues here: firstly, studies have shown anticholinergics can cause confusion and may worsen dementia symptoms. Secondly, polypharmacy – the use of multiple medicines by individual patients – is becoming increasingly common, and this will increase the overall anti-cholinergic burden.
“In the last 20 years, the number of older people taking five or more medicines has quadrupled. Many of these medicines will have some anticholinergic activity and, in the light of today’s findings, we have to re-consider whether the benefits always outweigh the risks.
“One focus should be on de-prescribing at least some medicines. That means pharmacists, doctors and nurses working with patients who are prescribed multiple drugs, to ascertain if the benefits clearly outweigh the potential harm that could be caused by anticholinergics.
“We also need further research into anticholinergics – there’s plenty of evidence that they can cause short-term confusion and today’s findings suggest some anticholinergics are linked to long-term harm as well.”
Anticholinergics are used to treat a variety of conditions by blocking a key messenger in nerve cells in the body called acetylcholine. Commonly prescribed antidepressants with significant anticholinergic activity include Amitriptyline, Dosulepin and Paroxetine. The new research also shows a dementia risk associated with medicines prescribed for bladder conditions (such as Oxybutynin, Tolterodine and Solifenacin), and Parkinson’s (for example Procyclidine). It is not clear whether the link was causal.
The new study was led by Dr George Savva from the University of East Anglia. He said: “Globally, more than 50 million people are affected by dementia and this number is expected to grow to 132 million by 2050. As such, developing strategies to prevent dementia should be priority.”
Prof Chris Fox, Professor of Clinical Psychiatry at UEA’s Norwich Medical School and Consultant Psychiatrist, said: “Given how common dementia is, this reflects a potentially important risk to patients even though the associations are moderate. We don’t know exactly how anticholinergics might cause dementia. Further research is needed to understand possible reasons for this link. In the meantime, my advice as a doctor is that patients with any concerns continue taking their medicines until they have consulted their doctor or pharmacist.”
Collaborators on this grant included Aston University, Regenstrief Institute, Purdue University (both from the USA), the University of Aberdeen, the Royal College of Surgeons in Ireland, Newcastle University, the University of Cambridge and the University East Anglia (the study lead).