More than a quarter of elderly suffer adverse drug reactions

Women and patients on a higher number of medicines are at greater risk of suffering an adverse drug reaction, a study found.

More than a quarter of people on long-term medication experienced at least one adverse drug reaction (ADR) over six years.

Those prescribed 10 or more medicines had a threefold increased risk of experiencing a reaction such as nausea and swelling.

Researchers say the findings suggest those on multiple medications should be prioritised for regular reviews with their GPs.

In the biggest study to focus on adverse drug events by patients in primary care, scientists monitored 592 patients aged 70 years and older from 15 general practices in the Republic of Ireland over a six-year period.

Overall, the majority of adverse reactions identified were mild and resolved, they found.

Some 11 per cent were moderate in their severity while eight patients had to be admitted to hospital as a result of their reactions.

Women were at least 50 per cent more likely to have ADRs than men, as a result of the different biological make-up between sexes.

Professor Emma Wallace, from University College Cork, said researchers were keen to ascertain how common a problem this is and how severe the adverse drug reactions are.

She said: ‘We found that one in four older people experienced at least one adverse drug reaction over the six-year period. 

‘The majority of adverse drug reactions were clinically mild, but 11 per cent were moderate severity and eight patients experienced an emergency admission as a result of the adverse drug reaction.

‘We found that females and those prescribed increasing numbers of medicines were more likely to experience an adverse drug reaction. 

‘In particular, patients prescribed 10 or more medicines had a threefold increased risk of experiencing an adverse drug reaction.’

She added: ‘Women and men can respond differently to the effects of medications, both beneficial and harm, and also the way our bodies process and break down medications can vary by sex. 

‘The type of medications prescribed can vary between men and women also.’

ADRs can be difficult to identify in medically complex older adults as they often present as non-specific symptoms, scientists said.

Examples of adverse effects included dry mouth, ankle swelling, headaches and nausea, according to the findings published in the British Journal Of General Practice.

Meanwhile, the medication groups most commonly associated with ADRs included those taken for high blood pressure and other cardiac conditions, strong painkillers such as tramadol and antibiotics such as amoxicillin.

Researchers suggested stopping ineffective medications as a way of minimising the risks.