Anticholinergic effects on cognitive impairment in the elderly

Results of a study were published last week looking at the cumulative use of strong anticholinergics on the development of dementia in the elderly (those aged 65 years). ¹ The results revealed that long term use of one or several drugs with anticholinergic effects could be associated with an increased risk of dementia, including Alzheimer's disease.¹ Anticholinergics are used to treat the symptoms of overactive bladder (OAB), as well as depression and allergy related conditions such as hay fever.

OAB affects over 7 million adults in the UK² and can have a significant impact on quality of life. ³ It is also more common than angina and diabetes, ^{4, 5} and the symptoms can almost dominate people's lives - they restrict their freedom of movement, prevent them from participating in activities they previously enjoyed, cause stress, embarrassment and anxiety. OAB is also linked to depression.^{3, 6, 7, 8}

OAB is commonly treated by health care professionals with the use of anticholinergic medications. These target the muscarinic acetylcholine receptors in the bladder and have, for years, been the mainstay of pharmacological treatment for OAB.

There are many OAB drugs available and these differ in their likelihood to cause anticholinergic side effects outside of the bladder, which are known to include cognitive impairment in elderly subjects.

The impact of treating OAB in the elderly and easing symptoms should not be underestimated as with this patient population it can cause loss of independence,⁶ be linked to falls (especially with regards to the need to visit the toilet at night) which in turn are associated with fractures.⁶ OAB in elderly patients is therefore often associated with the progression of increasing frailty and dependence on others.

Many patients with OAB will continue to be treated successfully with anticholinergic drugs, but if there are concerns regarding high anticholinergic burden (e.g. in elderly patients on multiple treatments), alternative treatments for OAB are available, and should be considered, and NICE guidelines should be referred to. ⁹

Betmiga (mirabegron) is a selective β3-adrenoreceptor agonist that has been accepted for use by the SMC¹⁰ and is recommended by NICE¹¹ as an option for treating patients with symptoms of OAB in whom antimuscarinic drugs are contraindicated, clinically ineffective, or have unacceptable side effects. This means that Betmiga belongs to a different class of OAB therapeutics which does not contribute to anticholinergic burden. The decision regarding prescribing the most beneficial treatment for patients suffering OAB symptoms shall be based on judgement of health care practitioners.