A new study has found that a type of drug commonly used to treat high blood pressure in older people can actually increase the risk of patients experiencing low blood pressure after standing.

The finding by researchers at Trinity College Dublin is important because low blood pressure is associated with a heightened risk of falls, fragility and poor brain health.

Around two thirds of those aged over 50 years in Ireland suffer with high blood pressure.

The team behind the Irish Longitudinal Study on Ageing (TILDA) investigated beta blockers, which are regularly prescribed to keep blood pressure from getting too high.

The research, published in the journal Plos One, found those taking the medicine were three times more likely than those who were not to experience sustained reductions in blood pressure after periods of standing.

It also found that those using other popular blood pressure treatments, such as calcium channel blockers, diuretics and ACE inhibitors, had a blood pressure response similar to those who had no treatment at all.

Lead researcher Dr Mark Canney said it was therefore important that those with high blood pressure who are at risk of suffering from drops in pressure after standing as a result of the treatment they are on are identified.

According to TILDA, one in three people over 65 and half of over 80s fall every year, with serious injury and disability a common consequence.

"It is projected that by 2020 the cost of fall-related injuries in older people will rise to €922m-€1,077m," said Professor Rose Anne Kenny, Principal Investigator of TILDA and Director of the Falls and Blackout Unit at St James's Hospital.

"The benefits of drug treatment for hypertension must be weighed against potentially harmful effects."