Elderly patients are being put at risk of being ‘poisoned’ by their medicines because not enough research has been done on the best doses and drug interactions, a House of Lords committee has heard.

Experts also warned that the NHS was not equipped to deal with multi-morbidity in old age and was compounding the problem.

Speaking at the science and technology committee hearing on healthier living in old age, Sir Munir Pirmohamed, professor of molecular and clinical pharmacology at Liverpool University, said he routinely saw patients on 10, 15 or even more than 20 different medicines.

‘Those drugs are used at conventional doses and those doses have been tested in younger populations who had exclusion criteria for trials – so they have been tested in people who don’t have the multiple diseases,’ he said.

'So when we use a drug at a dose that is licensed at the moment, we are often poisoning the elderly because of the dosing that we are using.

‘This is largely because as you get older, your renal function declines, your hepatic function declines, other functions also decline and you also have drug-drug interactions.’

He added: ‘We need to change the medical model of care from the highly-specialised model of care that we have at the moment to a much more generalist care model with a multidisciplinary team that includes care of the elderly, people who know about drugs and general practitioners working together.’


'Vicious cycle'


Professor Pirmohamed added that the ‘vicious cycle’ of patients having poor compliance and deteriorating further because they are suffering the effects of drug interactions needs to be broken.

Research he had done showed that patients with multi-morbidity were having acute admissions to hospital around three or four times a year and multiple secondary care appointments, each time one new medicine was added on average.

‘It is very easy to prescribe drugs but hard to stop them,’ he said.

He told the committee that better understanding was needed of the most appropriate doses of medicines in the elderly but also more research should be done on the three and four-way drug interactions that occur when someone is taking a lot of medication.