Many older people with intellectual disabilities in Ireland are being prescribed high levels of certain medicines with negative side-effects that can affect their health and quality of life, a new study has found.

According to the findings, almost one-third of older people with intellectual disabilities are commonly prescribed anti-cholinergic medicines, which block a neurotransmitter called acetylcholine. This is involved in passing messages between nerve cells.

While these medicines are necessary in some clinical circumstances, they can lead to serious side-effects such as anxiety, confusion, memory problems, bladder problems, falls and an increased heart rate.

Researchers from Trinity College Dublin (TCD) and Aston University in the UK, found that around 30% of the people they studied were taking high levels of these anti-cholinergic medicines.

They also found that usage was higher among older people with intellectual disabilities compared to older people without these disabilities. Some 50% of older people with intellectual disabilities were taking these medicines compared to just 4% of older people without disabilities.

Those who were taking high levels of these medicines often reported daytime drowsiness and chronic constipation. Furthermore, around one-third of these medicines were found to be antipsychotics, which are powerful medicines originally developed to treat the symptoms of schizophrenia.

The researchers said that the findings show the need for regular and comprehensive reviews of medicines, as this would help to avoid the inappropriate prescribing of multiple medicines, especially anti-cholinergic medicine combinations.

"People with intellectual disabilities are at increased risk of more chronic illnesses as they grow older when compared to the general population. On the one hand, appropriate medication can help improve both longevity and quality of life. On the other hand, the use of multiple medications, in particular of psychotropic drugs, something more common in older adults with intellectual disabilities, means that anti-cholinergic related side-effects are of serious concern," commented Prof Mary McCarron of TCD.

Also commenting on the findings, Dr Maire O'Dwyer of TCD emphasised that these medicines can have a major impact on quality of life.

"If someone is experiencing day time drowsiness and chronic constipation among other side effects, that is bound to affect their ability to exercise, to socialise, to engage in society and go about their day-to-day activities. As people with intellectual disability continue to move away from institutional settings into community-based ones, their ability to stay active and connected is of increased importance," she noted.

Meanwhile, according to Dr Ian Maidment of Aston University, people with intellectual disabilities ‘are among the most vulnerable of society'.

"We found very high levels of anti-cholinergic usage compared with the general population. More worryingly such usage was associated with drowsiness and constipation - precisely the type of side-effects we would want to avoid. Overall, this study adds to the increasing evidence that prescribing in people with intellectual disabilities is sub-optimal," he said.

The researchers noted that it would take ‘a multidisciplinary team of healthcare professionals to be able to tackle these problems for each person'.

"This study shows that establishing and empowering these teams must be a priority in order to optimise the use of medicines in the care of people with intellectual disability," commented Dr Martin Henman of TCD.

Details of these findings are published in the British Journal of Psychiatry.